The Board of Trinseo S.A. solicits your proxy for the General Meeting to be held on June 14, 2021, and at any adjournments or postponements of the General Meeting, for the purposes set forth in the Notice of the General Meeting of Shareholders included in this proxy statement. As used in this proxy statement, the terms "we," "us," "our" "Company" or "Trinseo" refer to Trinseo S.A. Proxy materials, including this proxy statement and the Annual Report for our fiscal year ended December 31, 2020 ("fiscal 2020") are being first provided to shareholders on or before April 30, 2021. Our registered address is 26-28, rue Edward Steichen, L 2540 Luxembourg, Grand Duchy of Luxembourg.

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QUESTIONS AND ANSWERS ABOUT THE
GENERAL MEETING AND THE PROXY MATERIALS

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QUESTIONS AND ANSWERS ABOUT THE MERGER

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QUESTIONS AND ANSWERS ABOUT THE MERGER

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QUESTIONS AND ANSWERS ABOUT THE MERGER

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SUMMARY OF MERGER PROPOSALS

This summary highlights selected information from this Proxy Statement concerning the Merger Proposal. It does not contain all of the information that may be important to you. To understand the Merger more fully, and for a more complete legal description of the Merger, you should carefully read the entire Proxy Statement, including the Annexes. The Common Draft Terms, in the form attached as Annex A to this Proxy Statement, is the legal document that governs the Merger. The Proposed Constitution substantially in the form attached to this Proxy Statement as Annex B, will govern Trinseo PLC upon completion of the Merger. We encourage you to read those documents carefully.

Parties to the Merger

Trinseo S.A.    Trinseo S.A. (NYSE: TSE) is a public limited liability company (société anonyme) formed in 2010 and existing under the laws of Luxembourg. We are a leading global materials company and manufacturer of plastics, latex binders and synthetic rubber, including various advanced specialty products and sustainable solutions. Our products are incorporated into a wide range of our customers' products throughout the world, including products for automotive applications, tires, carpet and artificial turf backing, coated paper, specialty paper and packaging board, food packaging, appliances, medical devices, consumer electronics and construction applications, among others. The Company's registered office is at 26-28, rue Edward Steichen, L 2540 Luxembourg, Grand Duchy of Luxembourg.

Trinseo PLC.    Trinseo Limited was incorporated as a private limited company under the laws of Ireland on May 27, 2015 as "Tribus Investments Limited" and was renamed "Trinseo Limited" on April 7, 2021. Prior to the Effective Date, Trinseo Limited will be re-registered as an Irish public limited company and renamed "Trinseo PLC". To date, Trinseo Limited has not engaged in any business or conducted any activities other than in connection with its formation and the Merger. The registered office of Trinseo PLC will be Sir John, Rogerson's Quay, Riverside One, Dublin 2, D02 X576, Ireland and Trinseo PLC's telephone number will be +1-610-240-3200.

The Merger

Trinseo S.A. shareholders are being asked to approve the Merger in accordance with the Common Draft Terms at the General Meeting. Contingent upon the approval of the Common Draft Terms, and assuming the other conditions to the Merger in the Common Draft Terms are satisfied or waived, on the Effective Date Trinseo S.A. shareholders will receive an ordinary share of Trinseo PLC for every ordinary share of Trinseo S.A. that they then hold, on a one-for-one basis. As a result of the Merger, Trinseo PLC will become our new public holding company with a NYSE trading symbol of "TSE".

Steps Required to Effect the Merger

On June 14, 2021, we will hold the General Meeting to allow shareholders of record to vote on the Merger proposals, including approval of the Merger and the Common Draft Terms.

Luxembourg.

After the Merger Proposal and resolution to enter into the Merger has been approved by Trinseo S.A. shareholders at the General Meeting, the following steps must be taken in Luxembourg in order to effect the Merger:

•

Luxembourg notary before whom the General Meeting is held will issue a pre-merger certificate attesting that all formalities required in Luxembourg in connection with the merger have been duly effected which shall be delivered to Trinseo PLC in accordance with Art. 1021-12(2) of the Luxembourg law of 10 August 1915 on commercial companies as amended from time to time (the "Luxembourg Law");



•

Upon receipt of the Final Order, the Luxembourg Trade and Company Register will deregister Trinseo S.A. which will have ceased to exist as of the Effective Date.

Ireland.

Following shareholder approval, the following steps must occur for Trinseo PLC to complete the Merger:

•

Application will be made to the Irish High Court for a pre-merger certificate; and



•

Subject to issuance of a pre-merger certificate by the Irish High Court and the issuance of a pre-merger certificate by a Luxembourg civil law notary, an application will be made to the Irish High Court for an order to confirm legal scrutiny of the Merger and to set the Effective Date. The hearing of this application will be advertised in Iris Oifigiúil, the international editions of The Financial Times and/or The Wall Street Journal and/or such other publications as the Irish High Court may prescribe. Trinseo S.A. shareholders may attend the approval hearing and make representations at such meeting.

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Effectiveness.    If all of the conditions are satisfied or waived (and we do not abandon the Merger before obtaining the Irish High Court's Order), the Merger will take effect on the Effective Date. We currently anticipate the Merger to be effective in October 2021. Once the Merger takes effect as provided for in the Irish Regulations, it may not be declared null and void, and the Final Order specifying the Effective Date shall constitute conclusive evidence of the effectiveness of the Merger.

In connection with the Merger, the following steps will occur by operation of law on the Effective Date:

1.

Trinseo S.A. will be merged with and into Trinseo PLC, with Trinseo PLC as the surviving entity, and Trinseo S.A. will cease to exist upon consummation of the Merger;

2.

all assets and liabilities of Trinseo S.A. as at the Effective Date shall transfer to, and be assumed by Trinseo PLC by universal succession of title and by operation of law;

3.

the activities of the Trinseo S.A. business shall be continued by Trinseo PLC;

4.

each Trinseo S.A. shareholder (other than Trinseo S.A.) will receive an ordinary share of Trinseo PLC for every ordinary share of Trinseo S.A. that they then hold, on a one-for-one basis;

5.

in accordance with Luxembourg Law, all Trinseo S.A. treasury shares held by Trinseo S.A. will be canceled by operation of law;

6.

all legal proceedings pending by or against Trinseo S.A. will be continued with the substitution, for Trinseo S.A., of Trinseo PLC as a party; and

7.

contracts, agreements or instruments to which Trinseo S.A. is a party will by operation of law succeed to Trinseo S.A. and be construed and have effect as if Trinseo PLC had been a party thereto instead of Trinseo S.A., and Trinseo PLC will have the same rights and be subject to the same obligations to which Trinseo S.A. is subject to under such contracts, agreements or instruments.

8.

without prejudice to the foregoing, the consequences of the Merger set out in Regulation 19(1) of the Irish Regulations and Art 1021-17 of the Luxembourg Law shall apply to the Merger.

As a result of the Merger, Trinseo S.A. shareholders will become Trinseo PLC shareholders, and Trinseo S.A. will cease to exist.

After the Merger, you will own an interest in a company that will continue to conduct the same functions as conducted by Trinseo S.A. before the Merger. The number of Trinseo PLC shares you will own immediately following the Merger will be the same as the number of Trinseo S.A. shares you owned immediately before the Merger.

Upon completion of the Merger, we will remain subject to SEC reporting requirements and will continue to report our consolidated financial results in U.S. dollars and in accordance with U.S. GAAP. As required by Irish law, in connection with annual general meetings of Trinseo PLC commencing with its 2022 annual general meeting, the Trinseo PLC Irish statutory accounts will also be made available to Trinseo PLC shareholders.

Reasons for the Merger (See page 36)

Our Board believes that giving effect to the Merger will be in the best interests of the Trinseo group and our shareholders. In arriving at this determination, our Board consulted with Trinseo S.A.'s management along with its legal and tax advisors and considered various factors in its deliberations. Our Board concluded that the Merger will simplify our regulatory and governance requirements, provide dividend withholding tax benefits to shareholders, allow for increased flexibility to allocate capital through share issuances or repurchases, and provide Trinseo with other operational efficiencies and cost reductions. The Merger will also complement the Company's proposed plan to create a global business services center in Ireland. If Trinseo S.A. shareholders approve this proposal, the Merger will effectively change Trinseo S.A.'s legal domicile from Luxembourg to Ireland and will result in other changes of a legal nature, the most significant of which are described below under the caption "Comparison of Rights of Shareholders and Governance under the Articles to the Proposed Constitution" in Proposal 3.

We cannot assure you that the anticipated benefits of the Merger will be realized. In addition to the potential benefits described above, the Merger will expose us and you to some risks. These risks include, but are not limited to: changes to your rights as a Trinseo S.A. shareholder; the potential application of stamp duty on the transfer of Trinseo PLC shares after the Merger; the potential application of Irish dividend withholding tax; and the potential application of Irish capital acquisitions tax to a gift or inheritance of Trinseo PLC shares.

For further detail, see "Proposal 1: The Merger—Reasons for the Merger" and "Risk Factors" for more information.

Tax Considerations of the Merger (See page 15)

U.S. Federal Income Tax.    The Merger is intended to qualify as a "reorganization" within the meaning of Section 368(a) of the Code. If the Merger is so treated as a "reorganization", (i) a U.S. Holder will not recognize any gain or loss as a result of the Merger, (ii) a U.S. Holder's adjusted tax basis in the Trinseo PLC shares received will be equal to the adjusted tax basis of the Trinseo S.A. shares exchanged therefor and (iii) the holding period of the Trinseo PLC shares received as a result of the exchange will include the holding period of Trinseo S.A. shares surrendered in the Merger.

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Irish Tax.    It is anticipated that the Merger should not be a taxable event from an Irish tax perspective. As a result, it is anticipated that the Merger should not give rise to any Irish capital gains tax consequences for Trinseo S.A. shareholders. No stamp duty will be payable on the Merger. Irish stamp duty may, depending upon the manner in which Trinseo PLC shares are held, be payable in respect of transfers of Trinseo PLC shares after the Merger. It is expected that for the majority of transfers of Trinseo PLC shares following the Merger, no stamp duty should arise. Transfers of Trinseo PLC shares effected by means of the transfer of book-entry interests in DTC should not be subject to Irish stamp duty, subject to confirmation by the Irish Revenue Commissioners in advance of the Merger. However, if a shareholder holds their Trinseo PLC shares directly rather than beneficially through DTC, any transfer of the Trinseo PLC shares could be subject to Irish stamp duty (currently at the rate of 1% of the higher of the price paid or the market value of the shares acquired). For further detail, see "Material Tax Considerations Relating to the Merger—Material Irish Tax Considerations."

Luxembourg Tax.    We believe that (i) Trinseo S.A. shareholders who are not resident in Luxembourg will generally not be subject to Luxembourg (corporate) income tax in respect of the Merger, subject to certain exceptions, and (ii) Trinseo S.A. shareholders who are resident in Luxembourg may be subject to Luxembourg (corporate) income tax in respect of the Merger, depending on the tax regime applicable to such holder. For further detail, see "Material Tax Considerations Relating to the Merger—Material Luxembourg Tax Considerations."

You should consult your personal tax advisors concerning the tax consequences of receiving, holding, disposing of, and receiving dividends on, Trinseo PLC shares received pursuant to the Merger.

Comparison of Rights of Shareholders and Governance (See page 40)

Your rights as a Trinseo S.A. shareholder are currently governed by Luxembourg law and our Articles. Following the Merger, you will become a Trinseo PLC shareholder and your rights as a Trinseo PLC shareholder will be governed by Irish law and the Proposed Constitution. The legal system governing companies organized under Irish law differs from the legal system governing companies organized under Luxembourg law. As a result, while many of the principal attributes of Trinseo S.A. shares and Trinseo PLC shares will be similar under Luxembourg and Irish law, differences will exist.

We summarize your rights as a Trinseo PLC shareholder under "Description of Trinseo PLC shares" and provide a summary comparing your rights as a Trinseo S.A. shareholder and a Trinseo PLC shareholder under the heading "Comparison of Rights of Shareholders and Governance" in Proposal 3. A copy of the Proposed Constitution is attached as Annex B to this Proxy Statement.

Stock Exchange Listing

The Merger is not expected to affect our stock exchange listing on the New York Stock Exchange (the "NYSE"). Trinseo S.A. shares are expected to continue to trade on the NYSE until the Effective Date. Immediately following the Effective Date, Trinseo PLC shares will be listed on the NYSE under the symbol "TSE," the same symbol under which Trinseo S.A. shares are currently listed.

Upon completion of the Merger, we will remain subject to SEC reporting requirements, the mandates of the Sarbanes-Oxley Act of 2002 and the applicable corporate governance rules of the NYSE, and we will continue to report our consolidated financial results in U.S. dollars and in accordance with U.S. GAAP.

Accounting Treatment of the Merger (See page 38)

Under U.S. GAAP, the Merger represents a transaction between entities under common control. Assets and liabilities transferred between entities under common control are accounted for at historical cost. Accordingly, the assets and liabilities of Trinseo PLC will be reflected at their carrying amounts in the accounts of Trinseo S.A. at the time of the Merger .

Irish Constitution Proposal

We are asking shareholders to approve, by non-binding advisory vote, the Proposed Constitution of Trinseo PLC, in the form attached hereto as Annex B (Proposal 3). The Proposed Constitution is the governing document which will be in effect at the time the Merger is completed. If the Merger is not approved, this proposal will have no effect, but the Merger is not conditioned on the separate approval of this advisory proposal. We are asking shareholders to vote for the Proposed Constitution on an advisory basis, to allow shareholders the opportunity to vote for the Proposed Constitution separately from the Merger Proposal. A comparison of the rights of Trinseo S.A. shareholders under our existing Articles and Luxembourg law to the rights of Trinseo PLC shareholders under the Proposed Constitution and Irish law is set forth in detail in the language of the proposal. We encourage you to read these differences carefully when making your decision on how to vote.

We strongly encourage all shareholders that vote "for" the Merger Proposal to also vote "for" the Irish Constitution Proposal, to allow the Company to proceed with the Merger as intended and set forth in the Merger Proposal.

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Advisory Constitution Proposals

We are also asking shareholders to vote, on a non-binding advisory basis, to approve certain differences between our Articles and the Proposed Constitution (Proposal 4). These differences are being presented as three separate advisory proposals, and pertain to (a) changes in our authorized share capital; (b) changes in our share issuance authority and preemptive rights, and (c) changes to the advance notice provision for shareholder director nominations. If the Merger is not approved, this proposal will have no effect, but the Merger is not conditioned on the separate approval of these advisory proposals.

We strongly encourage shareholders who vote "for" the Merger Proposal to also vote "for" these three advisory proposals. We believe these provisions are necessary to adequately address the needs of Trinseo PLC following the Merger.

Description of Distributable Profits

Under Irish law, Trinseo PLC may only pay dividends, make other distributions and, generally, effect share repurchases and redemptions from "distributable profits" shown in Trinseo PLC's unconsolidated financial statements prepared in accordance with the Irish Companies Act and filed with the Irish Companies Registration Office.

Immediately following the Merger, Trinseo PLC will not have any distributable profits of its own. Accordingly, you are being asked to approve the Distributable Profits Proposal (Proposal 5), to enable, subject to the effectiveness of the Merger, the creation of distributable profits of Trinseo PLC under Irish law by reducing the entire share premium of Trinseo PLC as created by the Merger (or such lesser amount as may be approved by the Trinseo PLC Board). Trinseo PLC must also seek approval from the Irish High Court.

The Trinseo S.A. Board recommends that Trinseo S.A. shareholders vote for the Distributable Profits Proposal, though it is not a condition to the Merger. If the Distributable Profits Proposal is not approved by Trinseo S.A. shareholders and the Irish High Court, Trinseo PLC will not be able to pay dividends, make other distributions and, generally, effect share repurchases and redemptions until such time as it has otherwise generated sufficient distributable profits from its operational activities following the Merger.

Recommendation of the Board

Our Board recommends that Trinseo S.A. shareholders vote "FOR" the Merger Proposal, "FOR" the Irish Constitution Proposal, "FOR" the Advisory Constitution Proposals and "FOR" the Distributable Profits Proposal.

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RISK FACTORS

Before you decide how to vote, you should carefully consider the following risk factors related to the Merger, in addition to the other information contained in this Proxy Statement, including, without limitation, our Form 10-K and subsequent filings with the SEC.

Your rights as a Trinseo S.A. shareholder will change as a result of the Merger due to differences between Irish law and Luxembourg law.

Your rights as a Trinseo S.A. shareholder are currently governed by Luxembourg law and our Articles. Following the Merger, you will become a Trinseo PLC shareholder and your rights as a Trinseo PLC shareholder will be governed by Irish law and the Proposed Constitution. The legal system governing companies organized under Irish law differs from the legal system governing companies organized under Luxembourg law. As a result, while many of the principal attributes of Trinseo S.A. shares and Trinseo PLC shares will be similar under Luxembourg and Irish law, differences will exist, which, in some cases, may provide fewer protections for Trinseo PLC shareholders. We summarize your rights as a Trinseo PLC shareholder under "Description of Trinseo PLC shares" and provide a summary comparing your rights as a Trinseo S.A. shareholder and a Trinseo PLC shareholder under the heading "Comparison of Rights of Shareholders and Governance under the Articles to the Proposed Constitution" in Proposal 3.

Attempted takeovers of Trinseo PLC will be subject to the Irish Takeover Rules and will be under the supervisory jurisdiction of the Irish Takeover Panel.

Following the completion of the Merger, Trinseo PLC will be subject to the Irish Takeover Panel Act 1997, as amended, and the Irish Takeover Rules promulgated thereunder, which regulate the conduct of takeovers of, and certain other relevant transactions affecting, Irish public limited companies listed on certain stock exchanges, including the NYSE.

Under the Irish Takeover Rules, if an acquisition of Trinseo PLC shares were to increase the aggregate holding of the acquirer and its concert parties to a level that represents 30% or more of the voting rights of Trinseo PLC, the acquirer and, in certain circumstances, its concert parties would be required (except with the consent of the Irish Takeover Panel) to make an offer for the outstanding Trinseo PLC shares at a price not less than the highest price paid by the acquirer or its concert parties for Trinseo PLC shares during the previous 12 months. This requirement would also be triggered by an acquisition of Trinseo PLC shares by a person holding (together with its concert parties) Trinseo PLC shares that represent between 30% and 50% of the voting rights in the company if the effect of such acquisition were to increase that person's percentage of the voting rights by 0.05% within a 12-month period.

For a description of certain takeover provisions applicable to Trinseo PLC, see "Description of Trinseo PLC shares—Irish Takeover Rules" beginning on page 29.

Anti-takeover provisions in the Proposed Constitution could make an acquisition of Trinseo PLC more difficult, limit attempts by Trinseo PLC shareholders to replace or remove our directors and management team and limit the market price of Trinseo PLC shares.

The Proposed Constitution will contain provisions that may delay or prevent a change of control, discourage bids at a premium over the market price of Trinseo PLC shares and adversely affect the market price of Trinseo PLC shares and the voting and other rights of Trinseo PLC shareholders. These provisions include: (1) permitting the Trinseo PLC board of directors (the "Trinseo PLC Board") to issue preference shares without shareholder approval, with such rights, preferences and privileges as they may designate; (2) allowing the Trinseo PLC Board to adopt a shareholder rights plan upon such terms and conditions as it deems expedient; (3) establishing an advance notice procedure for shareholder proposals to be brought before the annual general meeting, including proposed nominations of persons for election to the Trinseo PLC Board; (4) permitting the Trinseo PLC Board or directors to fill vacancies on the Trinseo PLC Board in certain circumstances; and (5) imposing particular approvals and other requirements in relation to certain business combinations. For a description of certain takeover provisions applicable to Trinseo PLC, see "Description of Trinseo PLC shares—Irish Takeover Rules" beginning on page 29.

These provisions do not make Trinseo PLC immune from takeovers. However, these provisions may frustrate or prevent any attempts by shareholders to replace or remove the management team by making it more difficult for shareholders to replace members of the Trinseo PLC Board.

If the Distributable Profits Proposal is not approved by Trinseo S.A. shareholders and the Irish High Court, Trinseo PLC will not be able to pay dividends, make other distributions and, generally, effect share repurchases and redemptions until such time as it has otherwise generated sufficient distributable profits from its operational activities following the Merger.

Under Irish law, Trinseo PLC may only pay dividends, make other distributions and, generally, effect share repurchases and redemptions from "distributable profits" shown in Trinseo PLC's unconsolidated financial statements prepared in accordance with the Irish Companies Act and filed with the Irish Companies Registration Office.

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Immediately following the Merger, Trinseo PLC will not have any distributable profits. Accordingly, you are being asked to approve the Distributable Profits Proposal, to enable, subject to the effectiveness of the Merger, the creation of distributable profits of Trinseo PLC under Irish law by reducing the entire share premium of Trinseo PLC (or such lesser amount as may be approved by the Trinseo PLC Board) resulting from the allotment and issuance of Trinseo PLC shares pursuant to the Merger, such that the reserve resulting from the cancellation of such share premium will be treated as distributable profits.

In addition to the approval of Trinseo S.A. shareholders, the Distributable Profits Proposal also requires the approval of the Irish High Court. If the Distributable Profits Proposal is approved by Trinseo S.A. shareholders prior to the Effective Date and the Merger becomes effective, Trinseo PLC intends to seek the approval of the Irish High Court for the Distributable Profits Proposal as soon as practicable following the Effective Date. Although Trinseo S.A. is not aware of any reason why the Irish High Court would not approve the Distributable Profits Proposal, such approval is a matter of judicial discretion and there is no guarantee that such approval will be forthcoming.

If the Distributable Profits Proposal is not approved by Trinseo S.A. shareholders and the Irish High Court, Trinseo PLC will not be able to pay dividends, make other distributions and, generally, effect share repurchases and redemptions until such time as it has otherwise generated sufficient distributable profits from its operational activities following the Merger.

We may choose to abandon or delay the Merger. In addition, we may not be able to receive the requisite governmental approvals to consummate the Merger.

We currently expect to complete the Merger in October 2021. However, our Board may delay the Merger for a significant time or may abandon the Merger after the General Meeting and before the issuance of the Final Order because, among other reasons, of a determination by our Board that completing the Merger is no longer in our best interest or the best interests of Trinseo S.A. shareholders or may not result in the benefits we expect. Additionally, we may not be able to obtain the requisite court or other approvals. For further detail, see "Proposal 1: The Merger—Conditions to the Consummation of the Merger" and "Proposal 1: The Merger—Amendment, Termination or Delay."

If Trinseo PLC shares are not eligible for deposit and clearing within the facilities of DTC, then transactions in Trinseo PLC shares may be disrupted.

The facilities of DTC are a widely used mechanism that allow for rapid electronic transfers of securities between the participants in the DTC system, which include many large banks and brokerage firms.

Upon the completion of the Merger, Trinseo PLC shares will be eligible for deposit and clearing within the DTC system. We expect to enter into arrangements with DTC whereby Trinseo PLC will agree to indemnify DTC for any Irish stamp duty that may be assessed upon it as a result of its service as a depositary and clearing agency for Trinseo PLC shares. We expect that these actions, among others, will result in DTC agreeing to accept the shares for deposit and clearing within its facilities upon completion of the Merger.

DTC is not obligated to accept Trinseo PLC shares for deposit and clearing within its facilities at the closing of the Merger and, even if DTC does initially accept the Trinseo PLC shares, it will generally have discretion, as it currently has with regard to Trinseo S.A. shares, to cease to act as a depositary and clearing agency for the shares. If DTC determined prior to the completion of the Merger that Trinseo PLC shares are not eligible for clearance within the DTC system, then we would not expect to complete the transactions contemplated by this Proxy Statement in their current form. However, if DTC determined at any time after the completion of the Merger that Trinseo PLC shares were not eligible for continued deposit and clearance within its facilities, then we believe Trinseo PLC shares would not be eligible for continued listing on a U.S. securities exchange and trading in Trinseo PLC shares would be disrupted. Although we expect Trinseo PLC would pursue alternative arrangements to preserve its listing and maintain trading, any such disruption could have a material adverse effect on the trading price of Trinseo PLC shares.

Transfers of Trinseo PLC shares, other than by means of the transfer of book-entry interests in the DTC, may be subject to Irish stamp duty.

It is expected that for the majority of transfers of Trinseo PLC shares, no stamp duty should arise. Transfers of Trinseo PLC shares effected by means of the transfer of book-entry interests in DTC should not be subject to Irish stamp duty, subject to confirmation by the Irish Revenue Commissioners in advance of the Merger. However, if a shareholder holds their Trinseo PLC shares directly rather than beneficially through DTC, any transfer of the Trinseo PLC shares could be subject to Irish stamp duty (currently at the rate of 1% of the higher of the price paid or the market value of the shares acquired).

A Trinseo PLC shareholder who directly holds Trinseo PLC shares of record may transfer those shares into his or her own broker account to be held through DTC (or vice versa) and this should not give rise to Irish stamp duty provided that there is no change in the beneficial ownership of the shares as a result of the transfer and the transfer is not in contemplation of a sale of the shares by a beneficial owner to a third party.

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Due to the potential Irish stamp duty charge on transfers of Trinseo PLC shares held outside DTC, those Trinseo S.A. shareholders who do not hold their Trinseo S.A. shares through DTC (or through a broker who in turn holds such shares through DTC) should, upon completion of the Merger, consider holding Trinseo PLC shares received by them through DTC.

For further detail, see "Material Tax Considerations Relating to the Merger—Material Irish Tax Considerations."

You should consult your personal tax advisors as to the tax consequences of disposing of Trinseo PLC shares received pursuant to the Merger.

Dividends you receive after the Merger may be subject to Irish dividend withholding tax ("DWT"), subject to exemptions.

As an Irish tax resident company, we may be required to deduct DWT (currently at the rate of 25%) from dividends paid on Trinseo PLC shares unless Trinseo PLC shareholders qualify for a DWT exemption. Trinseo PLC shareholders resident in the EU, and other countries with which Ireland has a tax treaty (which includes the United States) should generally be eligible for an exemption from DWT, provided that, in each case, they file a valid DWT Form with the Irish Revenue Commissioners. However, Trinseo PLC shareholders residing in other countries may be subject to DWT. For further detail, see "Material Tax Considerations Relating to the Merger—Material Irish Tax Considerations."

You should consult your personal tax advisors as to the tax consequences of receiving dividends on Trinseo PLC shares.

Trinseo PLC shares received by means of a gift or inheritance may be subject to Irish capital acquisitions tax ("CAT"), subject to any exemptions and reliefs.

CAT could apply to a gift or inheritance of Trinseo PLC shares irrespective of the place of residence, ordinary residence or domicile of the parties. This is because Trinseo PLC shares are regarded as property situated in Ireland as the share register of Trinseo PLC must be held in Ireland. The person who receives the gift or inheritance has primary liability for CAT. For further detail, see "Material Tax Considerations Relating to the Merger—Material Irish Tax Considerations."

We recommend that you consult your personal advisors to consider your estate planning needs, including transfers of Trinseo PLC shares to family members and charitable organizations.

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MATERIAL TAX CONSIDERATIONS RELATING TO THE MERGER

Material U.S. Federal Income Tax Considerations

The following is a general discussion of the material U.S. federal income tax consequences of the Merger to U.S. Holders (as defined below) of Trinseo S.A. shares, and of the subsequent ownership and disposition of Trinseo PLC shares received by such U.S. Holders in the Merger. This discussion does not address any U.S. federal income tax consequences of the Merger to non-U.S. Holders, except to the limited extent discussed below under "U.S. Federal Income Tax Consequences of the Merger to Trinseo S.A. Shareholders—Material Tax Consequences to Non-U.S. Holders".

This discussion is based on provisions of the Internal Revenue Code of 1986, as amended, the Treasury Regulations promulgated thereunder (whether final, temporary, or proposed), administrative rulings of the U.S. Internal Revenue Service (the "IRS"), and judicial decisions all as in effect on the date hereof, and all of which are subject to differing interpretations or change, possibly with retroactive effect. This discussion does not purport to be a complete analysis or listing of all potential U.S. federal income tax considerations that may apply to a U.S. Holder as a result of the Merger or as a result of the ownership and disposition of Trinseo PLC shares. In addition, this discussion does not address all aspects of U.S. federal income taxation that may be relevant to a particular U.S. Holders nor does it take into account the individual facts and circumstances of any particular U.S. Holders that may affect the U.S. federal income tax consequences to such U.S. Holder, and accordingly, is not intended to be, and should not be construed as, tax advice. This discussion does not address the U.S. federal 3.8% Medicare tax imposed on certain net investment income or any aspects of U.S. federal taxation other than those pertaining to the income tax (including any gift, estate or alternative minimum tax), nor does it address any tax consequences arising under any U.S. state and local tax laws. U.S. Holders should consult their own tax advisors regarding such tax consequences in light of their particular circumstances.

No ruling has been requested or will be obtained from the IRS regarding the U.S. federal income tax consequences of the Merger or any other related matter; thus, there can be no assurance that the IRS will not challenge the U.S. federal income tax treatment described below or that, if challenged, such treatment will be sustained by a court.

This summary is limited to considerations relevant to U.S. Holders that hold Trinseo S.A. shares, and, following consummation of the Merger, Trinseo PLC shares, as "capital assets" within the meaning of section 1221 of the Code (generally, property held for investment). This discussion does not address all aspects of U.S. federal income taxation that may be important to U.S. Holders in light of their individual circumstances, including U.S. Holders subject to special treatment under the U.S. tax laws, such as, for example:

•

banks or other financial institutions, underwriters, or insurance companies;



•

traders in securities who elect to apply a mark-to-market method of accounting;



•

real estate investment trusts and regulated investment companies;



•

tax-exempt organizations, qualified retirement plans, individual retirement accounts, or other tax-deferred accounts;



•

expatriates or former long-term residents of the United States;



•

partnerships or other pass-through entities or investors in such entities;



•

dealers or traders in securities, commodities or currencies;



•

grantor trusts;



•

U.S. Holders whose "functional currency" is not the U.S. dollar;



•

persons who received Trinseo S.A. shares or Trinseo PLC shares through the issuance of restricted stock under an equity incentive plan or through a tax-qualified retirement plan or otherwise as compensation;



•

persons who own (directly or through attribution) 10% or more (by vote or value) of the outstanding Trinseo S.A. shares, or, after the Merger, the outstanding Trinseo PLC shares; or



•

U.S. Holders holding Trinseo S.A. shares, or, after the Merger, Trinseo PLC shares, as a position in a "straddle," as part of a "synthetic security" or "hedge," as part of a "conversion transaction," or other integrated investment or risk reduction transaction.

As used in this Proxy Statement, the term "U.S. Holder" means a beneficial owner of Trinseo S.A. shares, and, after the Merger, Trinseo PLC shares received in the Merger, that is, for U.S. federal income tax purposes:

•

an individual who is a citizen or resident of the United States;



•

a corporation or other entity taxable as a corporation created or organized in or under the laws of the United States or any State thereof or the District of Columbia;

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•

an estate the income of which is subject to U.S. federal income tax regardless of its source; or



•

a trust (i) if a court within the United States is able to exercise primary supervision over the administration of the trust and one or more U.S. persons have the authority to control all substantial decisions of the trust, or (ii) that has a valid election in effect under applicable Treasury Regulations to be treated as a U.S. person for U.S. federal income tax purposes.

As used in this Proxy Statement, the term "non-U.S. Holder" means a beneficial owner of Trinseo S.A. shares, and, after the Merger, Trinseo PLC shares received in the Merger, other than a U.S. Holder or an entity or arrangement treated as a partnership for U.S. federal income tax purposes.

If a partnership, including for this purpose any entity or arrangement that is treated as a partnership for U.S. federal income tax purposes, is a beneficial owner of Trinseo S.A. shares, and, following consummation of the Merger, Trinseo PLC shares received in the Merger, the U.S. federal income tax treatment of a partner in such partnership generally will depend on the status of the partner and the activities of the partnership. A U.S. Holder that is a partnership and the partners in such partnership should consult their own tax advisors with regard to the U.S. federal income tax consequences of the Merger and the subsequent ownership and disposition of Trinseo PLC shares received in the Merger.

THIS SUMMARY DOES NOT PURPORT TO BE A COMPREHENSIVE ANALYSIS OR DESCRIPTION OF ALL POTENTIAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE MERGER. TRINSEO S.A. SHAREHOLDERS AND TRINSEO PLC SHAREHOLDERS SHOULD CONSULT WITH THEIR TAX ADVISORS REGARDING THE PARTICULAR TAX CONSEQUENCES TO THEM OF THE MERGER AND OF THE OWNERSHIP AND DISPOSITION OF TRINSEO PLC SHARES AFTER THE MERGER, INCLUDING THE APPLICABILITY AND EFFECTS OF U.S. FEDERAL, STATE, LOCAL, AND OTHER TAX LAWS.

U.S. Federal Income Tax Consequences of the Merger to Trinseo S.A. and Trinseo PLC

For U.S. federal income tax purposes, the Merger is intended to qualify as a "reorganization" within the meaning of Section 368(a)(1)(F) of the Code, i.e. a "mere change in identity, form, or place of organization of one corporation." Assuming that the Merger is treated as a reorganization under Section 368(a)(1)(F), neither Trinseo S.A. nor Trinseo PLC are expected to recognize any gain or loss for U.S. federal income tax purposes as a result of the Merger.

U.S. Federal Income Tax Consequences of the Merger to Trinseo S.A. Shareholders

Material Tax Consequences to U.S. Holders

Assuming that the Merger is treated as a reorganization under Section 368(a)(1)(F), (i) a U.S. Holder will not recognize any gain or loss as a result of the Merger, (ii) a U.S. Holder's adjusted tax basis in the Trinseo PLC shares received will be equal to the adjusted tax basis of the Trinseo S.A. shares exchanged therefor and (iii) the holding period of the Trinseo PLC shares received as a result of the exchange will include the holding period of Trinseo S.A. shares surrendered in the Merger.

Material Tax Consequences to Non-U.S. Holders

A non-U.S. holder generally will not be subject to U.S. federal income or withholding tax on gain realized, if any, on the exchange of Trinseo S.A. shares for Trinseo PLC shares in the Merger.

U.S. Federal Income Tax Consequences to U.S. Holders of the Ownership and Disposition of Trinseo PLC shares

The following discussion is a summary of certain material U.S. federal income tax consequences of the ownership and disposition of Trinseo PLC shares to U.S. Holders who receive such Trinseo PLC shares pursuant to the Merger.

Distributions on Trinseo PLC shares

The gross amount of any distribution on Trinseo PLC shares that is made out of Trinseo PLC's current or accumulated earnings and profits (as determined for U.S. federal income tax purposes) generally will be included in the gross income of a U.S. Holder as ordinary dividend income on the date such distribution is actually or constructively received by such U.S. Holder. Any such dividends paid to corporate U.S. Holders generally will not qualify for the dividends-received deduction that may otherwise be allowed under the Code. In general, the dividend income would be treated as foreign source, passive income for U.S. federal foreign tax credit limitation purposes.

Dividends received by non-corporate U.S. Holders (including individuals), subject to the discussion below under "—Passive Foreign Investment Company Status," from a "qualified foreign corporation" may be eligible for reduced rates of taxation, provided that certain holding period requirements and other conditions are satisfied. For these purposes, a non-U.S. corporation will be treated as a qualified foreign corporation with respect to dividends paid by that corporation on shares that are readily tradable on an established securities market in the United States. U.S. Treasury guidance indicates that shares listed on the NYSE (which the Trinseo PLC shares are expected to be) will be considered readily tradable on an established securities market in the United States. There can be no assurance that Trinseo PLC shares will be considered readily tradable on an established securities market in future years. Trinseo PLC will not

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constitute a qualified foreign corporation for purposes of these rules if it is a passive foreign investment company, or "PFIC," for the taxable year in which it pays a dividend or for the preceding taxable year. For further details, see the discussion below under "—Passive Foreign Investment Company Status."

The amount of any dividend paid in foreign currency will be the U.S. dollar value of the foreign currency distributed by Trinseo PLC, calculated by reference to the exchange rate in effect on the date the dividend is includible in the U.S. Holder's income, regardless of whether the payment is in fact converted into U.S. dollars on the date of receipt. Generally, a U.S. Holder should not recognize any foreign currency gain or loss if the foreign currency is converted into U.S. dollars on the date the payment is received. However, any gain or loss resulting from currency exchange fluctuations during the period from the date the U.S. Holder includes the dividend payment in income to the date such U.S. Holder actually converts the payment into U.S. dollars will be treated as ordinary income or loss. That currency exchange income or loss (if any) generally will be income or loss from U.S. sources for foreign tax credit limitation purposes.

To the extent that the amount of any distribution made by Trinseo PLC on Trinseo PLC shares exceeds Trinseo PLC's current and accumulated earnings and profits for a taxable year (as determined under U.S. federal income tax principles), the distribution will first be treated as a tax-free return of capital, causing a reduction in the adjusted basis of the U.S. Holder's Trinseo PLC shares, and to the extent the amount of the distribution exceeds the U.S. Holder's tax basis, the excess will be taxed as capital gain recognized on a sale or exchange as described below under "—Sale, Exchange, Redemption or Other Taxable Disposition of Trinseo PLC shares."

It is possible that Trinseo PLC is, or at some future time will be, at least 50% owned by U.S. persons. Dividends paid by a foreign corporation that is at least 50% owned by U.S. persons may be treated as U.S. source income (rather than foreign source income) for foreign tax credit purposes to the extent the foreign corporation has more than an insignificant amount of U.S. source income. The effect of this rule may be to treat a portion of any dividends paid by Trinseo PLC as U.S. source income. Treatment of the dividends as U.S. source income in whole or in part may limit a U.S. holder's ability to claim a foreign tax credit with respect to foreign taxes payable or deemed paid in respect of the dividends paid by Trinseo PLC or on other items of foreign source, passive income for U.S. federal foreign tax credit limitation purposes.

Sale, Exchange, Redemption or Other Taxable Disposition of Trinseo PLC shares

Subject to the discussion below under "—Passive Foreign Investment Company Status," a U.S. Holder generally will recognize gain or loss on any sale, exchange, redemption, or other taxable disposition of Trinseo PLC shares in an amount equal to the difference between the amount realized on the disposition and such U.S. Holder's adjusted tax basis in such Trinseo PLC shares. Any gain or loss recognized by a U.S. Holder on a taxable disposition of Trinseo PLC shares generally will be capital gain or loss and will be long-term capital gain or loss if the Trinseo PLC shareholder's holding period in such Trinseo PLC shares exceeds one year at the time of the disposition. Preferential tax rates may apply to long-term capital gains of non-corporate U.S. Holders (including individuals). The deductibility of capital losses is subject to limitations. Any gain or loss recognized by a U.S. Holder on the sale or exchange of Trinseo PLC shares generally will be treated as a U.S. source gain or loss.

Passive Foreign Investment Company Status ("PFIC")

Notwithstanding the foregoing, certain adverse U.S. federal income tax consequences could apply to a U.S. Holder if Trinseo PLC is treated as a PFIC for any taxable year during which such U.S. Holder holds Trinseo PLC shares. A non-U.S. corporation, such as Trinseo PLC, will be classified as a PFIC for U.S. federal income tax purposes for any taxable year in which, after the application of certain look-through rules, either (i) 75% or more of its gross income for such year is "passive income" (as defined in the relevant provisions of the Code) or (ii) 50% or more of the value of its assets (determined on the basis of a quarterly average) during such year consists of assets which produce or are held for the production of passive income. Passive income generally includes dividends, interest, royalties, rents, annuities, net gains from the sale or exchange of property producing such income and net foreign currency gains.

Trinseo PLC is not currently expected to be treated as a PFIC for U.S. federal income tax purposes, but this conclusion is a factual determination made annually and, thus, is subject to change. With certain exceptions, Trinseo PLC shares would be treated as stock in a PFIC with respect to a U.S. Holder if Trinseo PLC were a PFIC at any time during that U.S. Holder's holding period in such U.S. Holder's Trinseo PLC shares. There can be no assurance that Trinseo PLC will not be treated as a PFIC for any taxable year or at any time during a U.S. Holder's holding period.

If Trinseo PLC were to be treated as a PFIC, unless a U.S. Holder elects to be taxed annually on a mark-to-market basis with respect to its Trinseo PLC shares or the U.S. Holder makes an effective qualified electing fund election, gain realized on any sale or exchange of such Trinseo PLC shares and certain distributions received with respect to such Trinseo PLC shares could be subject to additional U.S. federal income taxes, plus an interest charge on certain taxes treated as having been deferred under the PFIC rules. In addition, dividends received with respect to Trinseo PLC shares would not constitute qualified dividend income eligible for preferential tax rates if Trinseo PLC is treated as a PFIC for the taxable year of the distribution or for its preceding taxable year. If a U.S. Holder makes an effective qualified electing fund election, or QEF Election, the U.S. Holder will be required to include in gross income each year, whether or not we make distributions, as capital gains, such U.S. Holder's pro rata share of Trinseo PLC's net capital gains and, as ordinary income, such U.S. Holder's pro rata share of our earnings in excess of Trinseo PLC's net capital gains. We do not currently intend to

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provide the information necessary for U.S. holders to make QEF Elections if we are treated as a PFIC for any taxable year. U.S. Holders should consult their own tax advisors regarding the application of the PFIC rules to their investment in Trinseo PLC shares.

Information Reporting and Backup Withholding

U.S. Holders that own at least five percent of the Trinseo S.A. shares (by vote or value) or Trinseo S.A. shares with a tax basis of $1,000,000 or more immediately before the Merger will be required to file certain Section 368(a) reorganization statements. Trinseo S.A. shareholders should consult their tax advisors about the other information reporting requirements that could be applicable to the exchange of Trinseo S.A. shares for Trinseo PLC shares in the Merger.

In general, information reporting requirements will apply to dividends received by U.S. Holders of Trinseo PLC shares, and the proceeds received on the disposition of Trinseo PLC shares effected within the United States (and, in certain cases, outside the United States), in each case, other than U.S. Holders that are exempt recipients (such as corporations). Backup withholding (currently at a rate of 24%) may apply to such amounts if the U.S. Holder fails to provide an accurate taxpayer identification number (generally on an IRS Form W-9 provided to the paying agent or the U.S. Holder's broker) or is otherwise subject to backup withholding.

Certain U.S. Holders holding specified foreign financial assets with an aggregate value in excess of the applicable dollar threshold are required to report information to the IRS relating to Trinseo PLC shares, subject to certain exceptions (including an exception for Trinseo PLC shares held in accounts maintained by U.S. financial institutions), by attaching a complete IRS Form 8938, Statement of Specified Foreign Financial Assets, with their tax return, for each year in which they hold Trinseo PLC shares. Such U.S. Holders should consult their own tax advisors regarding information reporting requirements relating to their ownership of Trinseo PLC shares.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or credit against a holder's U.S. federal income tax liability, if any, provided the required information is timely furnished to the IRS.

Material Irish Tax Considerations

Irish Tax Considerations

The following is a summary of the material Irish tax consequences of the Merger for certain beneficial owners of Trinseo S.A. shares in connection with the Merger, including the ownership and disposal of Trinseo PLC shares received by such holders pursuant to the Merger. This discussion is based on Irish tax laws and the practice of the Irish Revenue Commissioners in effect on the date of this Proxy Statement, all of which are subject to differing interpretations or change, possibly with retroactive effect. This summary does not purport to be a complete analysis or listing of all potential Irish tax considerations that may apply to a holder as a result of the Merger or as a result of the ownership and disposition of Trinseo PLC shares by a holder. In addition, this discussion does not address all aspects of Irish taxation that may be relevant to particular holders nor does it take into account the individual facts and circumstances of any particular holder that may affect the Irish tax consequences to such holder. Accordingly, this summary is not intended to be, and should not be construed as, tax advice. This discussion does not address Irish pay related social insurance, nor does it address any tax consequences specific to stock options, free shares or warrants. The summary is not exhaustive, and Trinseo S.A. shareholders should consult their tax advisors about the Irish tax consequences (and tax consequences under the laws of other relevant jurisdictions) of the transactions and of the acquisition, ownership and disposal of Trinseo PLC shares.

There can be no assurance that the Irish tax authorities will not challenge the Irish tax treatment described below or that, if challenged, such treatment will be sustained by a court.

The summary applies only to Trinseo S.A. shareholders who will own Trinseo PLC shares as capital assets and does not apply to other categories of Trinseo S.A. shareholders, such as dealers in securities, trustees, insurance companies, collective investment schemes, pension funds and Trinseo S.A. shareholders who have, or who are deemed to have, acquired their Trinseo PLC shares by virtue of an Irish office or employment (performed or carried on in Ireland).

Irish Capital Gains Tax ("CGT")

The rate of tax on chargeable gains (where applicable) in Ireland is 33%.

Non-resident Trinseo PLC shareholders

Trinseo PLC shareholders who are neither resident nor ordinarily resident in Ireland for Irish tax purposes and do not hold their Trinseo PLC shares in connection with a trade carried on by such Trinseo PLC shareholders through an Irish branch or agency will not be liable for Irish tax on chargeable gains realized on a subsequent disposal of their Trinseo PLC shares.

Trinseo S.A. shareholders who are neither resident nor ordinarily resident in Ireland for Irish tax purposes and do not hold their Trinseo S.A. shares in connection with a trade carried on by such Trinseo S.A. shareholders through an Irish branch or agency will not

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be liable for Irish tax on chargeable gains on the cancellation of their Trinseo S.A. shares, or on receipt of Trinseo PLC shares pursuant to the Merger.

Irish resident Trinseo PLC shareholders

The receipt by a Trinseo S.A. shareholder who is either resident or ordinarily resident in Ireland for Irish tax purposes or who holds their Trinseo S.A. shares in connection with a trade carried on in Ireland through a branch or agency of Trinseo PLC shares pursuant to the Merger will generally have the following consequences for such Trinseo S.A. shareholders.

The receipt of Trinseo PLC shares should be treated as a reconstruction for the purposes of Irish CGT. Accordingly, such Trinseo S.A. shareholders should not be treated as having made a disposal of their Trinseo S.A. shares for the purposes of Irish CGT to the extent that they receive Trinseo PLC shares. Instead, Trinseo PLC shares should be treated as the same asset as Trinseo S.A. shares in respect of which they are issued and treated as acquired at the same time and for the same acquisition cost as those Trinseo S.A. shares for Irish tax purposes. A chargeable gain or allowable loss should therefore only arise on a subsequent disposal of Trinseo PLC shares.

A subsequent disposal of Trinseo PLC shares by a Trinseo PLC shareholder who is resident or ordinarily resident in Ireland for Irish tax purposes or who holds his, her or its Trinseo PLC shares in connection with a trade carried on by such person through an Irish branch or agency will, subject to the availability of any exemptions and reliefs, generally be within the charge to Irish CGT.

A Trinseo PLC shareholder who is an individual and who is temporarily not resident in Ireland may, under Irish anti-avoidance legislation, still be liable to Irish tax on any chargeable gain realized upon a subsequent disposal of Trinseo PLC shares during the period in which such individual is a non-resident.

Stamp Duty

The rate of stamp duty (where applicable) on transfers of shares of Irish incorporated companies is 1% of the price paid or the market value of the shares acquired, whichever is greater. Where Irish stamp duty arises, it is generally a liability of the transferee.

No stamp duty will be payable on the Merger. Irish stamp duty may, depending upon the manner in which Trinseo PLC shares are held, be payable in respect of transfers of Trinseo PLC shares after the Merger.

Shares held through DTC

A transfer of Trinseo PLC shares effected by means of a transfer of book-entry interests in Trinseo PLC shares within the facilities of DTC will not be subject to Irish stamp duty, subject to confirmation from the Irish Revenue Commissioners in advance of the Merger.

Shares Held Directly and Shares Held Outside of DTC or Transferred Into or Out of DTC

A transfer of Trinseo PLC shares where any party to the transfer holds such shares directly (i.e., outside of DTC) may be subject to Irish stamp duty. Shareholders wishing to transfer their shares into (or out of) DTC may do so provided that:

•

there is no change in the beneficial ownership of such shares as a result of the transfer; and



•

the transfer into (or out of) DTC is not effected in contemplation of a sale of such shares by a beneficial owner to a third party.

Due to the potential Irish stamp charge on transfers of Trinseo PLC shares, it is strongly recommended that those Trinseo S.A. shareholders who do not hold their Trinseo S.A. shares through DTC should arrange for the transfer of their Trinseo S.A. shares into DTC as soon as possible and before the Merger is effected. It is also strongly recommended that any person who wishes to acquire Trinseo PLC shares after the Effective Date of the Merger acquires such Trinseo PLC shares through DTC.

Withholding Tax on Dividends

Distributions made by Trinseo PLC will, in the absence of one of many exemptions, be subject to Irish DWT currently at a rate of 20%.

For DWT purposes, a distribution includes any distribution that may be made by Trinseo PLC to Trinseo PLC shareholders, including cash dividends, non-cash dividends and additional stock taken in lieu of a cash dividend. Where an exemption does not apply in respect of a distribution made to a particular Trinseo PLC shareholder, Trinseo PLC is responsible for withholding DWT prior to making such distribution.

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General Exemptions

Irish domestic law provides that a non-Irish resident Trinseo PLC shareholder is not subject to DWT on dividends received from Trinseo PLC if such Trinseo PLC shareholder is beneficially entitled to the dividend and is either:

•

a person (not being a company) resident for tax purposes in a "relevant territory" (including the U.S.) and is neither resident nor ordinarily resident in Ireland (for a list of "relevant territories" for DWT purposes, please see Annex C to this Proxy Statement);



•

a company resident for tax purposes in a "relevant territory," provided such company is not under the control, whether directly or indirectly, of a person or persons who is or are resident in Ireland;



•

a company, wherever resident, that is controlled, directly or indirectly, by persons resident in a "relevant territory" and who is or are (as the case may be) not controlled by, directly or indirectly, persons who are not resident in a "relevant territory";



•

a company, wherever resident, whose principal class of shares (or those of its 75% direct or indirect parent) is substantially and regularly traded on a stock exchange in Ireland, on a recognized stock exchange in a "relevant territory" or on such other stock exchange approved by the Irish Minister for Finance; or



•

a company, wherever resident, that is wholly owned, directly or indirectly, by two or more companies where the principal class of shares of each of such companies is substantially and regularly traded on a stock exchange in Ireland, on a recognized stock exchange in a "relevant territory" or on such other stock exchange approved by the Irish Minister for Finance;

and provided, in all cases noted above Trinseo PLC or, in respect of Trinseo PLC shares held through DTC, any qualifying intermediary appointed by Trinseo PLC, has received from the Trinseo PLC shareholder, where required, the relevant Irish Revenue Commissioners DWT forms (the "DWT Forms") prior to the payment of the dividend. In practice, in order to ensure sufficient time to process the receipt of relevant DWT Forms, the Trinseo PLC shareholder where required should furnish the relevant DWT Forms to:

•

its broker (and the relevant information is further transmitted to any qualifying intermediary appointed by Trinseo PLC) before the record date for the dividend (or such later date before the dividend payment date as may be notified to the shareholder by the broker) if the Trinseo PLC shareholder holds Trinseo PLC shares through DTC; or



•

Trinseo PLC transfer agent at least seven business days before the record date for the dividend if Trinseo PLC shares are held directly.

Links to the various DWT Forms are available at: http://www.revenue.ie/en/tax/dwt/forms/index.html

The information on such website does not constitute a part of, and is not incorporated by reference into, this Proxy Statement.

Such forms are generally valid, subject to a change in circumstances, until December 31 of the fifth year after the year in which such forms were completed.

For non-Irish resident Trinseo PLC shareholders who cannot avail themselves of one of Ireland's domestic law exemptions from DWT, it may be possible for such Trinseo PLC shareholders to rely on the provisions of a double tax treaty to which Ireland is party to reduce the rate of DWT.

Trinseo PLC shares Held by Residents of "Relevant Territories"

Trinseo PLC shareholders who are residents of "relevant territories," must satisfy the conditions of one of the exemptions referred to above under the heading "—General Exemptions", including the requirement to furnish valid DWT forms, in order to receive dividends without suffering DWT. If such Trinseo PLC shareholders hold their Trinseo PLC shares through DTC, they must provide the appropriate DWT forms to their brokers (so that such brokers can further transmit the relevant information to a qualifying intermediary appointed by Trinseo PLC) before the record date for the dividend (or such later date before the dividend payment date as may be notified to the Trinseo PLC shareholder by the broker). If such Trinseo PLC shareholders hold their Trinseo PLC shares directly, they must provide the appropriate DWT forms to Trinseo PLC's transfer agent at least seven business days before the record date for the dividend. It is strongly recommended that such Trinseo PLC shareholders complete the appropriate DWT Forms and provide them to their brokers or Trinseo PLC's transfer agent, as the case may be, as soon as possible after receiving their Trinseo PLC shares.

If any Trinseo PLC shareholder who is resident in a "relevant territory" receives a dividend from which DWT has been withheld, the Trinseo PLC shareholder may be entitled to a refund of DWT from the Irish Revenue Commissioners provided the Trinseo PLC shareholder is beneficially entitled to the dividend.

Trinseo PLC shares Held by Residents of Ireland

Most Irish tax resident or ordinarily resident Trinseo PLC shareholders (other than Irish resident companies that have completed the appropriate DWT forms) will be subject to DWT in respect of dividends paid on their Trinseo PLC shares.

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Shareholders that are residents of Ireland, but are entitled to receive dividends without DWT, must complete the appropriate DWT Forms and provide them to their brokers (so that such brokers can further transmit the relevant information to a qualifying intermediary appointed by Trinseo PLC) before the record date for the dividend (or such later date before the dividend payment date as may be notified to the Trinseo PLC shareholder by the broker) (in the case of Trinseo PLC shares held through DTC), or to Trinseo PLC's transfer agent at least seven business days before the record date for the dividend (in the case of Trinseo PLC shares held directly).

Trinseo PLC shares Held by Other Persons

Trinseo PLC shareholders that do not fall within any of the categories specifically referred to above may nonetheless fall within other exemptions from DWT. If any Trinseo PLC shareholders are exempt from DWT, but receive dividends subject to DWT, such Trinseo PLC shareholders may apply for refunds of such DWT from the Irish Revenue Commissioners.

Trinseo PLC will rely on information received directly or indirectly from brokers and its transfer agent in determining where Trinseo PLC shareholders reside, whether they have provided the required DWT Forms.

Income Tax on Dividends Paid on Trinseo PLC shares

Irish income tax may arise for certain persons in respect of dividends received from Irish resident companies.

A Trinseo PLC shareholder that is not resident or ordinarily resident in Ireland and that is entitled to an exemption from DWT generally has no liability to Irish Income Tax or the universal social charge on a dividend from Trinseo PLC. An exception to this position may apply where such Trinseo PLC shareholder holds Trinseo PLC shares through a branch or agency in Ireland through which a trade is carried on.

A Trinseo PLC shareholder that is not resident or ordinarily resident in Ireland and that is not entitled to an exemption from DWT generally has no additional liability to Irish income tax or the universal social charge. An exception to this position may apply where the Trinseo PLC shareholder holds Trinseo PLC shares through a branch or agency in Ireland through which a trade is carried. The DWT deducted by Trinseo PLC discharges the liability to Irish income tax.

Irish resident or ordinarily resident Trinseo PLC shareholders may be subject to Irish tax and/or the universal social charge on dividends received from Trinseo PLC. Credit should be available against this Irish tax for any DWT declared by Trinseo PLC. Such Trinseo PLC shareholders should consult their own tax advisors.

Withholding Tax on Share Repurchases

It is anticipated that Irish DWT should not generally apply to payments made by Trinseo PLC on the redemption or repurchase of its own shares. This is because an Irish tax resident company that is a quoted company is not treated as making a distribution for Irish tax purposes on making payments to redeem, repay or repurchase its own shares, provided the redemption or repurchase does not form part of a scheme or arrangement the main purpose (or one of the main purposes of which) is to enable shareholders to participate in the profits of the company without receiving a dividend.

Capital Acquisitions Tax

Irish capital acquisitions tax ("CAT") is comprised of principally gift tax and inheritance tax. CAT could apply to a gift or inheritance of Trinseo PLC shares irrespective of the place of residence, ordinary residence or domicile of the parties. This is because Trinseo PLC shares are regarded as property situated in Ireland as the share register of Trinseo PLC must be held in Ireland. The person who receives the gift or inheritance has primary liability for CAT.

CAT is currently levied at a rate of 33% above certain tax-free thresholds. The appropriate tax-free threshold is dependent upon (i) the relationship between the donor and the donee and (ii) the aggregation of the values of previous gifts and inheritances received by the donee from persons within the same group threshold. Gifts and inheritances passing between spouses are exempt from CAT. Trinseo PLC shareholders should consult their own tax advisors as to whether CAT is creditable or deductible in computing any domestic tax liabilities.

Material Luxembourg Tax Considerations

The information set out below is a general summary of certain material Luxembourg tax consequences in connection with the Merger. This summary is not a comprehensive or complete description of all the Luxembourg tax considerations that may be relevant for a particular Trinseo S.A. shareholder and it does not address the tax consequences that may arise in any jurisdiction other than Luxembourg in connection with the Merger. For Luxembourg tax purposes, a Trinseo S.A. shareholder may include an individual who or an entity that does not have the legal title to the Trinseo S.A. shares, but to whom nevertheless Trinseo S.A. shares, or the income thereof, are attributed based either on such individual or entity holding a beneficial interest in Trinseo S.A. shares or based on specific statutory provisions.

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MATERIAL TAX CONSIDERATIONS RELATING TO THE MERGER

This summary is based on the tax laws of Luxembourg as in effect on the date of this Proxy Statement, including regulations, rulings and decisions of Luxembourg and its taxing and other authorities available in printed form on or before this date and now in effect, and as applied and interpreted by Luxembourg courts, without prejudice to any developments or amendments introduced at a later date and implemented with or without retroactive effect.

Any reference in this summary to Luxembourg or Luxembourg tax law are to the European part of the Grand Duchy of Luxembourg and its law, respectively, only.

As this summary is intended as general information only, Trinseo S.A. shareholders should consult their own tax advisors as to the Luxembourg or other tax consequences of the Merger, including the application to their particular situations of the tax considerations discussed below.

This summary does not address the tax consequences for any Trinseo S.A. shareholder:

•

who is an individual and for whom the income or capital gains derived from Trinseo S.A. shares are attributable to employment activities, the income from which is taxable in Luxembourg;



•

who has, or that has, a substantial shareholding (more than 10% in the share capital in Trinseo S.A. the Luxembourg Income Tax Law (Loi modifiée du 4 Décembre 1967 concernant l'impôt sur le revenue, "LITL");



•

that is an entity that is resident or deemed to be resident in Luxembourg and that is, in whole or in part, not subject to or exempt from Luxembourg corporate income tax (such as qualifying pension funds);



•

that is an entity for which the income and/or capital gains derived from the Trinseo S.A. shares are exempt under the participation exemption as set out in LITL;



•

that is an exempt Undertaking for Collective Investment in Transferable Securities (UCITS) governed by the Luxembourg Law of 17 December 2010 or Alternative Investment Funds (AIFs) within the meaning of the Luxembourg Law of 12 July 2013;



•

who is, or that is, not considered the beneficial owner of Trinseo S.A. shares and/or the income and/or capital gains derived from Trinseo S.A. shares.

Taxation of Exchange of Trinseo S.A. shares for Trinseo PLC shares pursuant to the Merger

Luxembourg Resident Trinseo S.A. Shareholders

A Trinseo S.A. shareholder who is resident or deemed to be resident in Luxembourg for purposes of Luxembourg taxation (a "Luxembourg Resident"), may be subject to Luxembourg corporate income tax and Luxembourg municipal business tax in respect of the exchange of Trinseo S.A. shares for Trinseo PLC shares pursuant to the Merger, depending on the tax regime applicable to such holder.

Non-Luxembourg Resident Trinseo S.A. Shareholders

A Trinseo S.A. shareholder who is not, nor deemed to be, a Luxembourg Resident, (a "Non-Luxembourg Resident") is generally not subject to Luxembourg income tax or Luxembourg corporate income tax (as applicable) in respect of the exchange of Trinseo S.A. shares for Trinseo PLC shares pursuant to the Merger, provided that:

•

in case of a Non-Luxembourg Resident that is an entity, such entity has held a shareholding representing more than 10% in the share capital of Trinseo S.A. for more than six months from the acquisition of the shareholding;



•

in case of a Non-Luxembourg Resident that is an entity, which holds a substantial shareholding of more than 10% for less than six months, such entity is a qualified tax resident in a jurisdiction with which Luxembourg has concluded a double tax treaty under which the right to tax gains from the alienation of movable property is attributable to the State of which the alienator is a resident;



•

such Non-Luxembourg Resident does not derive profits from an enterprise or deemed enterprise, whether as an entrepreneur or pursuant to a co-entitlement to the net worth of such enterprise (other than as an entrepreneur or a shareholder) which enterprise is, in whole or in part, carried on through a permanent establishment in Luxembourg and to which enterprise or part of an enterprise, as the case may be, the Trinseo S.A. shares are attributable or deemed attributable;



•

in case of a Non-Luxembourg Resident who is an individual, such individual does not derive income or capital gains from Trinseo S.A. shares, as the case may be, that are taxable as benefits from 'miscellaneous activities performed in Luxembourg', which include the performance of activities in respect of Trinseo S.A. shares, that exceed regular, active portfolio management and also includes benefits resulting from a lucrative interest;



•

in case of a Non-Luxembourg Resident who is an individual, such individual is not entitled to a share in the profits of an enterprise effectively managed in Luxembourg, other than by way of the holding of securities or through an employment relationship, to which enterprise Trinseo S.A. shares or payments in respect of Trinseo S.A. shares are attributable; and



•

in case of a Non-Luxembourg Resident that is an entity, such entity is neither entitled to a share in the profits of an enterprise nor co-entitled to the net worth of an enterprise effectively managed in Luxembourg, other than by way of the holding of securities, to which enterprise Trinseo S.A. shares or payments in respect of Trinseo S.A. shares are attributable.

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DESCRIPTION OF TRINSEO PLC SHARES

The following description of the share capital of Trinseo PLC, including the Trinseo PLC ordinary shares to be issued in the Merger, is a summary. This summary does not purport to be complete and, along with the other statements in this section, is qualified in its entirety by reference to, and is subject to, the complete text of the Proposed Constitution that will be in effect on completion of the Merger, which will be substantially in the form filed as Annex B to this Proxy Statement. You are urged to read the Proposed Constitution and relevant provisions of the Irish Companies Act for a more complete understanding of the rights conferred by Trinseo PLC shares. The following summary is not a description of the Proposed Constitution currently in effect.

There are differences between our Articles and the Proposed Constitution. Certain provisions of Trinseo S.A.'s current Articles will not be replicated in the Proposed Constitution, and certain provisions that will be included in the Proposed Constitution are not in Trinseo S.A.'s current Articles. For further detail, see the section captioned "Comparison of Rights of Shareholders and Governance under the Articles to the Proposed Constitution" in Proposal 3, beginning on page 40.

Except where otherwise indicated, the description below reflects the Proposed Constitution as such document will be in effect as of the Effective Date.

Capital Structure

The rights of and restrictions applicable to the share capital of Trinseo PLC are prescribed in the Proposed Constitution, subject to the Irish Companies Act.

Authorized Share Capital

Trinseo PLC has an authorized share capital of US$50,000,000 and €25,000, comprised of 4,000,000,000 ordinary shares of US$0.01 each, 1,000,000,000 preferred shares of €0.01 each, and 25,000 deferred ordinary shares of €1.00 each.

The authorized share capital includes 25,000 deferred ordinary shares of €1.00 each, which were created solely to satisfy minimum statutory capital requirements that apply to all Irish public limited companies. The holders of the deferred ordinary shares are not entitled to receive any dividend or distribution, to attend, speak or vote at any general meeting, and effectively have no rights to participate in the assets of Trinseo PLC on a winding-up.

Immediately following completion of the Merger, Trinseo PLC will have an issued share capital comprising such number of Trinseo PLC ordinary shares as will be equal to the number of Trinseo S.A. ordinary shares issued immediately prior to completion of the Merger (excluding any treasury shares held by Trinseo S.A.), together with the 25,000 deferred ordinary shares. Each Trinseo PLC ordinary share will be entitled to one vote.

Under the Proposed Constitution, Trinseo PLC may issue new shares in Trinseo PLC up to its maximum authorized share capital. The authorized share capital may be increased or reduced by a resolution approved by a simple majority of the votes cast at a general meeting of shareholders of Trinseo PLC, referred to under Irish law as an "ordinary resolution".

Under Irish law, the directors of a company may issue new ordinary or preferred shares without shareholder approval once authorized to do so by the constitution or by an ordinary resolution adopted by the shareholders at a general meeting. The authorization may be granted for a maximum period of five years, at which point it must be renewed by the shareholders by an ordinary resolution. The Proposed Constitution authorizes the Trinseo PLC Board to allot shares in Trinseo PLC with an aggregate par value amount up to the maximum of its authorized but unissued share capital as at the date of adoption of the Proposed Constitution without approval from shareholders for a period of five years from the date of adoption of the Proposed Constitution.

Under the Proposed Constitution, the Trinseo PLC Board will be authorized to issue preferred shares with discretion as to the terms attaching to the preferred shares, including as to voting, dividend and conversion rights and priority relative to other classes of shares with respect to dividends and upon a liquidation. As described in the preceding paragraph, the authority to issue new shares in Trinseo PLC extends until five years from the date of the adoption of the Proposed Constitution, at which time it will expire unless renewed by Trinseo PLC's shareholders.

Notwithstanding this authority, under the Irish Takeover Rules (as defined below) the Trinseo PLC Board would not be permitted to issue any shares in Trinseo PLC, including ordinary or preferred shares, during a period when an offer has been made for Trinseo PLC or is believed to be imminent unless the issue falls within one of the exceptions described in the section below captioned "—Anti-Takeover Measures—Frustrating Action".

While Trinseo PLC does not have any current specific plans, arrangements or understandings, written or oral, to issue any preferred shares for any purpose, we are continually evaluating our financial position and analyzing the possible benefits of issuing additional debt securities, equity securities, convertible securities or a combination thereof in connection with, among other things: (i) repaying indebtedness; (ii) financing acquisitions; or (iii) strengthening our balance sheet. The availability of preferred shares gives us flexibility to

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respond to future capital raising, financing and acquisition needs and opportunities without the delay and expense associated with holding an extraordinary general meeting of Trinseo PLC's shareholders to obtain further approval.

Irish law does not recognize fractional shares held of record. Accordingly, the Proposed Constitution does not provide for the issuance of fractional shares, and our official Irish share register will not reflect any fractional shares.

Issued Share Capital

The Merger will result in each Trinseo S.A. ordinary share being cancelled and an equivalent number of Trinseo PLC ordinary shares being issued to the former Trinseo S.A. shareholders on a one-for-one basis.

In addition, 25,000 Trinseo PLC deferred ordinary shares will be held by MSFD Nominees Limited, to meet the Irish statutory minimum capital requirements of an Irish public limited company. The deferred ordinary shares will remain outstanding following the completion of the Merger and will continue to be held thereafter by MSFD Nominees Limited until redeemed at par or surrendered. These Trinseo PLC deferred ordinary shares (i) will not have any voting rights; (ii) will not entitle the holders thereof to any dividends or other distributions of Trinseo PLC; and (iii) will not entitle the holders thereof to participate in the surplus assets of Trinseo PLC on a winding-up beyond, in total, the nominal value of such Trinseo PLC deferred ordinary shares held (subject to the prior repayment of the amount paid-up on each of the Trinseo PLC shares plus an additional amount of $5,000,000 in cash per Trinseo PLC ordinary share). Accordingly, these Trinseo PLC deferred ordinary shares will not dilute the economic ownership of Trinseo PLC shareholders.

Under the Proposed Constitution, subject to the Irish Companies Act, the Trinseo PLC Board (or an authorized committee of the Trinseo PLC Board) is authorized to approve the allotment, issue, grant and disposal of, or otherwise deal with, shares, options, equity awards, rights over shares, warrants, other securities and derivatives (including unissued shares) in or of Trinseo PLC to such persons, at such times and on such terms as it thinks fit (including specifying the conditions of allotment of shares for the purposes of the Irish Companies Act).

Preemptive Rights

Under Irish law, certain statutory preemption rights apply automatically in favor of shareholders where shares are to be issued for cash. As permitted by Irish law, Trinseo PLC has opted to disapply these preemption rights in the Proposed Constitution, such that the Trinseo PLC Board will be authorized to allot shares of any class in Trinseo PLC with an aggregate par value amount up to the maximum of its authorized but unissued share capital as at the date of adoption of the Proposed Constitution without approval from Trinseo PLC's shareholders for a period of five years from the date of adoption of the Proposed Constitution.

Irish law requires this disapplication to be renewed at least every five years by 75% of the votes cast at a general meeting of shareholders, referred to under Irish law as a "special resolution". If the disapplication is not renewed, new equity shares in Trinseo PLC issued for cash must be offered to existing shareholders of Trinseo PLC on a pro rata basis to their existing shareholdings before the shares may be issued to any new shareholders.

Statutory preemption rights do not apply (i) where shares are issued for non-cash consideration (such as in a share-for-share acquisition); (ii) to the issue of non-equity shares (that is, shares that have the right to participate only up to a specified amount in any income or capital distribution); or (iii) where shares are issued pursuant to an employee stock option or similar equity plan.

Dividends

Under Irish law, Trinseo PLC will be able to declare dividends and make distributions only out of "distributable profits". Distributable profits are the accumulated realized profits of Trinseo PLC that have not previously been utilized in a distribution or capitalization less accumulated realized losses that have not previously been written off in a reduction or reorganization of capital, and include reserves created by way of a reduction of capital. In addition, no distribution or dividend may be paid or made by Trinseo PLC unless the net assets of Trinseo PLC are equal to, or exceed, the aggregate of Trinseo PLC's called-up share capital plus its undistributable reserves and the distribution does not reduce Trinseo PLC's net assets below such aggregate. Undistributable reserves include the undenominated capital, the capital redemption reserve fund and the amount by which Trinseo PLC's accumulated unrealized profits that have not previously been utilized by any capitalization exceed Trinseo PLC's accumulated unrealized losses that have not previously been written off in a reduction or reorganization of capital.

The determination as to whether Trinseo PLC has sufficient distributable profits to fund a dividend must be made by reference to its "relevant financial statements". The "relevant financial statements" will be either the last set of unconsolidated annual audited financial statements or other financial statements properly prepared in accordance with the Irish Companies Act, which give a "true and fair view" of Trinseo PLC's unconsolidated financial position and accord with accepted accounting practice and have been filed with the Irish Companies Registration Office.

The mechanism as to who declares a dividend and when a dividend becomes payable is governed by the Proposed Constitution. The Proposed Constitution authorizes the Trinseo PLC Board to declare interim dividends without approval from Trinseo PLC's shareholders if it considers that the financial position of Trinseo PLC justifies such payment. The Trinseo PLC Board may also

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recommend a dividend to be approved and declared by Trinseo PLC's shareholders at a general meeting. No dividend issued may exceed the amount recommended by the Trinseo PLC Board. The Proposed Constitution provides that dividends may be paid in cash, property or paid-up shares. Any cash payment may be made by check or warrant or sent by any electronic or other means of payment.

Except as otherwise provided by the rights attached to shares in Trinseo PLC, all shares in Trinseo PLC will carry a pro rata entitlement to the receipt of dividends. Unless provided for by the rights attached to shares in Trinseo PLC, no dividend or other monies payable by Trinseo PLC in respect of a share in Trinseo PLC shall bear interest.

If a dividend cannot be paid to a holder of shares in Trinseo PLC or otherwise remains unclaimed, the Trinseo PLC Board may pay it into a separate Trinseo PLC account and Trinseo PLC will not be a trustee in respect thereof. A dividend that remains unclaimed for a period of six years from the date of its declaration will be forfeited and will revert to Trinseo PLC.

Share Repurchases, Redemptions and Conversions

Repurchases and Redemptions

The Proposed Constitution provides that Trinseo PLC may purchase its own shares and redeem outstanding redeemable shares. Under the Irish law, shares can only be purchased or redeemed out of: (i) distributable profits; or (ii) the proceeds of a new issue of shares made for the purpose of the purchase or redemption.

Under the Irish Companies Act, a company may purchase its own shares either (i) "on-market" on a recognized stock exchange, which includes the NYSE; or (ii) "off-market" (i.e., otherwise than on a recognized stock exchange).

For Trinseo PLC to make "on-market" purchases of shares in Trinseo PLC, Trinseo PLC's shareholders must provide general authorization to Trinseo PLC to do so by way of an ordinary resolution. For so long as a general authority is in force, no additional shareholder authority for a particular "on-market" purchase is required. Such authority can be given for a maximum period of five years before it is required to be renewed and must specify: (i) the maximum number of shares that may be purchased; and (ii) the maximum and minimum prices that may be paid for the shares by specifying particular sums or providing a formula.

For an "off-market" purchase, the proposed purchase contract must be authorized by special resolution of the shareholders before the contract is entered into.

Separately, Trinseo PLC can redeem (as opposed to purchase) its redeemable shares once permitted to do so by the Proposed Constitution (without the requirement for additional shareholder authority). The Proposed Constitution provides that, unless the Trinseo PLC Board determines otherwise, any Trinseo PLC share that Trinseo PLC has agreed to acquire shall be automatically converted into a redeemable share. Accordingly, for purposes of the Irish Companies Act, unless the Trinseo PLC Board determines otherwise, the acquisition of Trinseo PLC shares by Trinseo PLC will technically be effected as a redemption of those Trinseo PLC shares. If the Proposed Constitution did not contain such provision, acquisitions of Trinseo PLC shares by Trinseo PLC would require to be effected as "on-market" or "off-market" purchases, as described above.

Repurchased and redeemed shares may be cancelled or held as treasury shares, provided that the par value of treasury shares held by Trinseo PLC at any time must not exceed 10% of the par value of Trinseo PLC's company capital (comprising the aggregate of all amounts of par value plus share premium paid for Trinseo PLC's shares plus certain other sums, which may be credited as such).

Trinseo PLC cannot exercise any rights in respect of any treasury shares. Treasury shares can either be held in treasury, re-issued "on-market" or "off-market" or cancelled. Depending on the circumstances of their acquisition, treasury shares may be held indefinitely or require to be cancelled after one or three years. The re-issue of treasury shares requires to be made pursuant to a valid and subsisting shareholder authority given by way of a special resolution.

Purchases by Subsidiaries

Under Irish law, a subsidiary of Trinseo PLC may purchase shares in Trinseo PLC either "on-market" or "off market," provided such purchases are authorized by Trinseo PLC's shareholders as outlined above. The redemption option is not available to a subsidiary of Trinseo PLC.

The number of shares in Trinseo PLC held by Trinseo PLC's subsidiaries at any time will count as treasury shares and will be included in any calculation of the 10% permitted treasury share threshold, as described above. While a subsidiary holds any of our shares, it cannot exercise voting rights in respect of those shares. The acquisition of our shares by a subsidiary must be funded out of distributable profits of the subsidiary.

Consolidation and Division; Subdivision

Under the Irish Companies Act, Trinseo PLC may, by ordinary resolution, consolidate and divide all or any of its share capital into shares of larger par value than its existing shares, or subdivide its shares into smaller amounts.

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Reduction of Share Capital

Trinseo PLC may reduce its share capital by way of a court approved procedure that also requires approval by special resolution of Trinseo PLC's shareholders at a general meeting.

Lien on Shares, Calls on Shares and Forfeiture of Shares

The Proposed Constitution provides that Trinseo PLC will have a first and paramount lien on every share that is not a fully paid-up share for an amount equal to the unpaid portion of such share. Subject to the terms of their allotment, directors may call for any unpaid amounts in respect of any shares in Trinseo PLC to be paid, and if payment is not made, the shares may be forfeited.

These provisions are customary in the constitution of an Irish public company limited by shares.

General Meetings of Shareholders

Trinseo PLC must hold its annual general meeting no more than nine months after its accounting year end (which is currently December 31).

In addition to any SEC mandated resolutions, the business of Trinseo PLC's annual general meeting is required to include: (a) the consideration of Trinseo PLC's statutory financial statements; (b) the review by shareholders of Trinseo PLC of Trinseo PLC's affairs; (c) the election and reelection of directors in accordance with the Proposed Constitution; (d) the appointment or reappointment of the Irish statutory auditors; (e) the authorization of the directors to approve the remuneration of the statutory auditors; and (f) the declaration of dividends (other than interim dividends).

The Proposed Constitution provides that the Trinseo PLC Board may convene general meetings of the Trinseo PLC's shareholders at any place they so designate. All general meetings, other than annual general meetings, are referred to as "extraordinary general meetings" at law.

If a general meeting is held outside Ireland, Trinseo PLC has a duty, at its expense, to make all necessary arrangements to ensure that Trinseo PLC's shareholders can by technological means participate in any such meeting without leaving Ireland.

The Proposed Constitution requires that notice of an annual general meeting of Trinseo PLC's shareholders must be delivered to the shareholders at least 21 clear days before the meeting. Shareholders must be notified of all general meetings (other than annual general meetings) at least 14 clear days prior to the meeting (provided that, in the case of an extraordinary general meeting for the passing of a special resolution, at least 21 clear days' notice is required). "Clear days" means calendar days and excludes (1) the date on which a notice is given, or a request received; and (2) the date of the meeting itself. The Company will continue to be bound by U.S. securities regulations governing notice & proxy statement delivery.

Calling Special Meetings of Shareholders

The Proposed Constitution provides that general meetings of shareholders may be called on the order of the Trinseo PLC board. Under Irish law, one or more shareholders representing at least 10% of the paid-up share capital of Trinseo PLC carrying voting rights have the right to requisition the holding of an extraordinary general meeting.

Serious Loss of Capital

If the directors of Trinseo PLC become aware that the assets of Trinseo PLC are half or less of the amount of Trinseo PLC's called-up share capital, the directors must convene an extraordinary general meeting of Trinseo PLC no later than 28 days after the earliest day on which that fact is known to a director (and the general meeting must be convened for a date not later than 56 days from that day). The meeting must be convened for the purpose of considering whether any, and if so what, measures should be taken to address the situation.

Quorum for Meetings of Shareholders

Under the Proposed Constitution, holders of at least a simple majority of the shares issued and entitled to vote at a general meeting constitute a quorum.

The necessary quorum at a separate general meeting of the holders of any class of shares is holders of at least a simple majority of that class of shares issued and entitled to vote.

Voting Rights

Under the Proposed Constitution, each Trinseo PLC shareholder is entitled to one vote for each Trinseo PLC share that they hold as of the record date for the meeting. A holder of the deferred ordinary shares is not entitled to a vote. No voting rights can be exercised in respect of any shares held as treasury shares, including shares held by subsidiaries.

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All resolutions at an annual general meeting or other general meeting will be decided on a poll.

On a poll every Trinseo PLC shareholder who is present, in person or by proxy, at the general meeting, is entitled to one vote for every Trinseo PLC share held by such Trinseo PLC shareholder.

On a separate general meeting of the holders of any class of shares, all votes will be taken on a poll and each holder of shares of the class will, on a poll, have one vote in respect of every share of that class held by such shareholder.

Under the Irish Companies Act and the Proposed Constitution, certain matters require "ordinary resolutions", which must be approved by at least a majority of the votes cast, in person or by proxy, by shareholders at a general meeting, and certain other matters require "special resolutions", which require the affirmative vote of at least 75% of the votes cast, in person or by proxy, by shareholders at a general meeting.

An ordinary resolution is needed (among other matters) to remove a director, provide, vary or renew the directors' authority to allot shares and to appoint directors (where appointment is by shareholders).

A special resolution is needed (among other matters) to: alter a company's constitution, exclude statutory preemptive rights on allotment of securities for cash (up to five years); reduce a company's share capital; re-register a public company as a private company (or vice versa); and approve a scheme of arrangement.

Cumulative voting is not recognized under Irish law.

Variation of Rights Attaching to a Class of Shares

Under the Proposed Constitution and the Irish Companies Act, any variation of class rights attaching to our issued shares must be approved by a special resolution of our shareholders of the affected class or with the consent in writing of the holders of three-quarters of all the votes of that class of shares.

Inspection of Books and Records

Generally, the register of Trinseo PLC's shareholders may be inspected during business hours (1) for free, by Trinseo PLC's shareholders; and (2) for a fee by any other person.

Documents may be copied for a fee.

The service contracts, if any, of Trinseo PLC's directors can be inspected by Trinseo PLC's shareholders without charge and during business hours. A "service contract" includes any contract under which such a director undertakes personally to provide services to the company or a subsidiary company, whether in that person's capacity as a director, an executive officer or otherwise. Service contracts with an unexpired term of less than three years are not required to be kept for inspection.

Trinseo PLC's shareholders have the right to receive a copy of the Proposed Constitution.

Trinseo PLC's shareholders may also inspect, without charge and during business hours, the minutes of meetings of the shareholders and obtain copies of the minutes for a fee.

In addition, the published annual statutory financial statements of Trinseo PLC are required to be available for Trinseo PLC's shareholders at a general meeting and a shareholder is entitled to a copy of these financial statements. Shareholders have a right to receive financial statements of subsidiaries that have previously been produced to an annual general meeting of such subsidiary in the preceding ten years. The auditors' report must be circulated to the Trinseo PLC's shareholders with the financial statements prepared in accordance with Irish law at least 21 days before the annual general meeting.

Under Irish law, the shareholders of a company do not have the right to inspect the corporate books of a subsidiary of that company.

Acquisitions

Shareholder Approval of Merger or Consolidation

Irish law recognizes the concept of a statutory merger in three situations: (1) a domestic merger where an Irish private limited company merges with another Irish company (not being a public limited company) under Part 9 of the Irish Companies Act; (2) a domestic merger where an Irish public limited company merges with another Irish company under Part 17 of the Irish Companies Act; and (3) a cross-border merger, where an Irish company merges with another company based in the European Economic Area ("EEA") under the European Communities (Cross-border Merger) Regulations 2008 of Ireland.

Under Irish law and subject to applicable U.S. securities laws and the NYSE's rules and regulations, where Trinseo PLC proposes to acquire another company, approval of Trinseo PLC's shareholders is not required, unless effected as a direct domestic merger or direct cross-border merger as referred to above.

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Under Irish law, where another company proposes to acquire Trinseo PLC, the requirement for the approval of Trinseo PLC's shareholders depends on the method of acquisition.

Schemes of Arrangement

Under Irish law, schemes of arrangement are arrangements or compromises between a company and any class of shareholders or creditors, and are used in certain types of reconstructions, amalgamations, capital reorganizations or takeovers (similar to a merger in the United States). Such arrangements require the approval of: (i) a majority in number of shareholders or creditors (as the case may be) representing 75% in value of the creditors or each class of creditors or shareholders or each class of shareholders present and voting either in person or by proxy at a special meeting convened by order of the court; and (ii) the Irish High Court.

Once approved by the requisite shareholder and creditor majority, sanctioned by the Irish High Court and becoming effective, all shareholders and/or, as the case may be, creditors of the relevant class are bound by the terms of the scheme. Dissenting shareholders and/or, as the case may be, creditors have the right to appear at the Irish High Court hearing and make representations in objection to the scheme.

Takeover Offer

The Irish Companies Act also provides that where (i) a takeover offer is made for shares, and (ii) following the offer, the offeror has acquired or contracted to acquire not less than 80% of the shares to which the offer relates, the offeror may require the other shareholders who did not accept the offer to transfer their shares on the terms of the offer.

A dissenting shareholder may object to the transfer on the basis that the offeror is not entitled to acquire its shares or to specify terms of acquisition different from those in the offer by applying to the court within 30 days of the date on which notice of the transfer was given. In the absence of fraud or oppression, and subject to strict compliance with the terms of the statute, the court is unlikely to order that the acquisition shall not take effect, but it may specify terms of the transfer that it finds appropriate.

A minority shareholder is also entitled in similar circumstances to require the offeror to acquire his or her shares on the terms of the offer.

Statutory Mergers

It is also possible for Trinseo PLC to be acquired by way of a domestic or cross-border statutory merger, as described above. Such mergers must be approved by a special resolution of shareholders. If the consideration being paid to shareholders is not all in the form of cash, dissenting shareholders may be entitled, in certain circumstances, to require that their shares be acquired for cash.

Related-Party Transactions

Trinseo PLC will be subject to the rules of the NYSE and the SEC regarding related-party transactions.

Under Irish law, certain transactions between Trinseo PLC and any director of Trinseo PLC are prohibited unless approved by Trinseo PLC's shareholders, such as loans, credit transactions and substantial property transactions. This prohibition extends to transactions with close personal relations and companies controlled by any such director.

Shareholder Suits

Under Irish law, the power to initiate a lawsuit on behalf of the company is generally a matter for its board of directors, and shareholders' rights to initiate a derivative lawsuit on behalf of the company are limited.

The central question at issue in deciding whether a shareholder may be entitled to bring a derivative action is whether, unless the action is brought, a wrong committed against the company would go unredressed.

The principal case law in Ireland indicates that to bring a derivative action, a person must first establish a prima facie case: (a) that the company is entitled to the relief claimed; and (b) that the action falls within one of the five exceptions derived from case law, as follows: (1) where an ultra vires or illegal act is perpetrated; (2) where more than a bare majority is required to ratify the "wrong" complained of; (3) where the shareholders' personal rights are infringed; (4) where a fraud has been perpetrated upon a minority by those in control; or (5) where the justice of the case requires.

While Irish law only permits a shareholder to bring a derivative action and initiate a lawsuit on behalf of the company in limited circumstances, it does permit a shareholder whose name is on the register of shareholders of a company to apply for a court order where the company's affairs are being conducted or the powers of the company's directors are being exercised: (1) in a manner oppressive to him or her or any of the shareholders; or (2) in disregard of his or her or their interests as shareholders.

Oppression connotes conduct that is burdensome, harsh and wrongful. Furthermore, the oppression or the disregard of interests must result from either the conduct of the affairs of the company or the exercise of the powers of the directors.

This is a statutory remedy and an Irish court has wide discretion to make such order as it sees fit.

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Lawsuits brought by a shareholder on behalf of the company must be brought exclusively in the courts of Ireland when they are related to or in connection with a derivative claim, an alleged breach of fiduciary or other duty by a director, officer or employee of Trinseo PLC or any other claim against Trinseo PLC or its directors, officers and employees under Irish law or pursuant to the constitution.

Disclosure of Interests in Shares

The Schedule 13D and Schedule 13G reporting regime will continue to apply to Trinseo PLC as it will have its shares registered under Section 12 of the Exchange Act.

Under the Irish Companies Act, a person must notify us if, as a result of a transaction, the person will become interested in three percent or more of our voting shares, or if as a result of a transaction a person who was interested in three percent or more of our voting shares ceases to be so interested. Under the Irish Companies Act, an "interest" is broadly defined and includes direct and indirect holdings, beneficial interests and, in some cases, derivative interests. Furthermore, a person's interests are aggregated with the interests of related persons and entities (including controlled companies). Where a person is interested in three percent or more of our voting shares, the person must notify us of any alteration of his or her interest that brings his or her total holding through the nearest whole percentage number, whether an increase or a reduction. The relevant percentage figure is calculated by reference to the aggregate nominal value of the voting shares in which the shareholder is interested as a proportion of the entire nominal value of our issued share capital (or any such class of share capital in issue). Where the percentage level of the person's interest does not amount to a whole percentage, this figure is rounded down to the next whole number. We must be notified within five business days of the transaction or alteration of the shareholder's interests that gave rise to the notification requirement. If a person fails to comply with these notification requirements, the person's rights in respect of any of our shares it holds will not be enforceable, either directly or indirectly, by action or legal proceeding. However, such person may apply to the court to have the rights attaching to such shares reinstated.

In addition, Irish law provides that a company may, by notice in writing, require a person whom the company knows or reasonably believes to be or to have been within the three preceding years, interested in its issued voting share capital to: (1) confirm whether this is or is not the case; and (2) if this is the case, to give further information that it requires relating to his or her interest and any other interest in the company's shares of which he or she is aware.

The disclosure must be made within a reasonable period as specified in the relevant notice which may be as short as one or two days. If the recipient of the notice fails to respond within the reasonable time period specified in the notice, we may apply to the Irish High Court for an order directing that the affected shares be subject to certain restrictions, as prescribed by the Irish Companies Act, as follows: (1) any transfer of those shares or, in the case of unissued shares, any transfer of the right to be issued with shares and any issue of shares, shall be void; (2) no voting rights shall be exercisable in respect of those shares; (3) no further shares shall be issued in right of those shares or in pursuance of any offer made to the holder of those shares; and (4) no payment shall be made of any sums due from us on those shares, whether in respect of capital or otherwise.

The court may also order that shares subject to any of these restrictions be sold with the restrictions terminating upon the completion of the sale.

In the event we are in an offer period pursuant to the Irish Takeover Rules, accelerated disclosure provisions apply for persons holding an interest in our securities of one percent or more.

Irish Takeover Rules

Following the completion of the Merger, Trinseo PLC will be subject to the Irish Takeover Panel Act 1997, as amended, and the Irish Takeover Rules promulgated thereunder, or the Irish Takeover Rules, which regulate the conduct of takeovers of, and certain other relevant transactions affecting, Irish public limited companies listed on certain stock exchanges, including the NYSE. The Irish Takeover Rules are administered by the Irish Takeover Panel, which has supervisory jurisdiction over such transactions. Among other matters, the Irish Takeover Rules operate to ensure that no offer is frustrated or unfairly prejudiced and, in the case of multiple bidders, that there is a level playing field. For example, pursuant to the Irish Takeover Rules, the Trinseo PLC Board will not be permitted, without approval from Trinseo PLC's shareholders, to take certain actions that might frustrate an offer for Trinseo PLC once the Trinseo PLC Board has received an approach that may lead to an offer or has reason to believe an offer is, or may be, imminent.

A transaction in which a third party seeks to acquire 30% or more of our voting rights and any other acquisitions of our securities will be governed by the Irish Takeover Panel Act 1997, as amended, and the Irish Takeover Rules and will be regulated by the Irish Takeover Panel. The "General Principles" of the Irish Takeover Rules and certain important aspects of the Irish Takeover Rules are described below.

General Principles

The Irish Takeover Rules are built on the following General Principles which will apply to any transaction regulated by the Irish Takeover Panel: (1) in the event of an offer, all holders of securities of the target company must be afforded equivalent treatment and, if a person acquires control of a company, the other holders of securities must be protected; (2) the holders of securities in the target company must have sufficient time and information to enable them to reach a properly informed decision on the offer; where it advises the holders of

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securities, the board of directors of the target company must give its views on the effects of the implementation of the offer on employment, employment conditions and the locations of the target company's place of business; (3) a target company's board of directors must act in the interests of that company as a whole and must not deny the holders of securities the opportunity to decide on the merits of the offer; (4) false markets must not be created in the securities of the target company, the bidder or any other company concerned by the offer in such a way that the rise or fall of the prices of the securities becomes artificial and the normal functioning of the markets is distorted; (5) a bidder can only announce an offer after ensuring that he or she can fulfill in full the consideration offered, if such is offered, and after taking all reasonable measures to secure the implementation of any other type of consideration; (6) a target company may not be hindered in the conduct of its affairs longer than is reasonable by an offer for its securities; and (7) a "substantial acquisition" of securities, whether such acquisition is to be effected by one transaction or a series of transactions, shall take place only at an acceptable speed and shall be subject to adequate and timely disclosure.

Mandatory Bid

Under certain circumstances, a person who acquires shares, or other voting securities, of a company may be required under the Irish Takeover Rules to make a mandatory cash offer for the remaining outstanding voting securities in that company at a price not less than the highest price paid for the securities by the acquirer, or any parties acting in concert with the acquirer, during the previous 12 months. This mandatory bid requirement is triggered if an acquisition of securities would increase the aggregate holding of an acquirer, including the holdings of any parties acting in concert with the acquirer, to securities representing 30% or more of the voting rights in a company, unless the Irish Takeover Panel otherwise consents. An acquisition of securities by a person holding, together with its concert parties, securities representing between 30% and 50% of the voting rights in a company would also trigger the mandatory bid requirement if, after giving effect to the acquisition, the percentage of the voting rights held by that person, together with its concert parties, would increase by 0.05% within a 12-month period. Any person, excluding any parties acting in concert with the holder, holding securities representing more than 50% of the voting rights of a company is not subject to these mandatory offer requirements in purchasing additional securities.

Voluntary Bid; Requirements to Make a Cash Offer and Minimum Price Requirements

If a person makes a voluntary offer to acquire outstanding Trinseo PLC shares, the offer price must not be less than the highest price paid for Trinseo PLC shares by the bidder or its concert parties during the three-month period prior to the commencement of the offer period. The Irish Takeover Panel has the power to extend the "look back" period to 12 months if the Irish Takeover Panel, taking into account the General Principles, believes it is appropriate to do so.

If the bidder or any of its concert parties has acquired Trinseo PLC shares (1) during the 12-month period prior to the commencement of the offer period that represent more than 10% of the outstanding Trinseo PLC shares or (2) at any time after the commencement of the offer period, the offer must be in cash or accompanied by a full cash alternative and the price per Trinseo PLC share must not be less than the highest price paid by the bidder or its concert parties during, in the case of (1) above, the 12-month period prior to the commencement of the offer period or, in the case of (2) above, the offer period. The Irish Takeover Panel may apply this Rule to a bidder who, together with its concert parties, has acquired less than 10% of the total Trinseo PLC shares in the 12-month period prior to the commencement of the offer period if the Irish Takeover Panel, taking into account the General Principles, considers it just and proper to do so.

An offer period will generally commence from the date of the first announcement of the offer or proposed offer.

Substantial Acquisition Rules

The Irish Takeover Rules also contain rules governing substantial acquisitions of shares and other voting securities which restrict the speed at which a person may increase his or her holding of shares and rights over shares to an aggregate of between 15% and 30% of the voting rights of the company. Except in certain circumstances, an acquisition or series of acquisitions of shares or rights over shares representing 10% or more of the voting rights of the company is prohibited, if such acquisition(s), when aggregated with shares or rights already held, would result in the acquirer holding 15% or more but less than 30% of the voting rights of the company and such acquisitions are made within a period of seven days. These rules also require accelerated disclosure of acquisitions of shares or rights over shares relating to such holdings.

Rights of Dissenting Shareholders

Irish law does not generally provide for appraisal rights. However Irish law provides for dissenters' rights in certain situations, as described below: (1) under a takeover offer, an offeror which has acquired or contracted to acquire not less than 80% of the shares to which the offer relates may require the other shareholders who did not accept the offer to transfer their shares on the terms of the offer. Dissenting shareholders have the right to apply to the High Court of Ireland for relief; (2) a takeover scheme of arrangement which has been approved by the requisite shareholder majority and sanctioned by the High Court of Ireland will be binding on all shareholders. Dissenting shareholders have the right to appear at the High Court hearing and make representations in objection to the scheme; and

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(3) in the case of a domestic or cross-border statutory merger, if the consideration being paid to shareholders is not all in the form of cash, dissenting shareholders may, in certain circumstances, be entitled to require that their shares be acquired for cash.

Anti-Takeover Measures

Frustrating Action

Under the Irish Takeover Rules, the Trinseo PLC Board is not permitted to take any action that might frustrate an offer for our shares once the Trinseo PLC Board has received an approach that may lead to an offer or has reason to believe that such an offer is or may be imminent, subject to certain exceptions. Potentially frustrating actions such as (1) the issue of shares, options, restricted share units or convertible securities; (2) material acquisitions or disposals; (3) entering into contracts other than in the ordinary course of business; or (4) any action, other than seeking alternative offers, which may result in frustration of an offer, are prohibited during the course of an offer or at any earlier time during which the Trinseo PLC Board has reason to believe an offer is or may be imminent. Exceptions to this prohibition are available where: (a) the action is approved by our shareholders at a general meeting; or (b) the Irish Takeover Panel has given its consent, where: (i) it is satisfied the action would not constitute frustrating action; (ii) our shareholders holding more than 50% of the voting rights state in writing that they approve the proposed action and would vote in favor of it at a general meeting; (iii) the action is taken in accordance with a contract entered into prior to the announcement of the offer, or any earlier time at which the Board considered the offer to be imminent; or (iv) the decision to take such action was made before the announcement of the offer and either has been at least partially implemented or is in the ordinary course of business.

Shareholder Rights Plan

Although the Proposed Constitution allows the Trinseo PLC Board to adopt a shareholder rights plan and to grant rights to subscribe for Trinseo PLC ordinary shares or preferred shares thereunder, Trinseo S.A. currently has no intention of adopting a shareholder rights plan or issuing share purchase rights. Irish law does not expressly authorize or prohibit companies from issuing share purchase rights or adopting a shareholder rights plan as an anti-takeover measure. However, there is no directly relevant case law on the validity of such plans under Irish law. In addition, such a plan would be subject to the Irish Takeover Rules and the General Principles underlying the Irish Takeover Rules.

Subject to the Irish Takeover Rules and the terms of the Proposed Constitution and any related shareholder approvals, the Trinseo PLC Board also has power to issue any of our authorized and unissued shares on such terms and conditions as it may determine, and any such action should be taken in Trinseo PLC's best interests. It is possible, however, that the terms and conditions of any issue of preference shares could discourage a takeover or other transaction that holders of some or a majority of the Trinseo PLC shares believe to be in their best interests or in which holders might receive a premium for their shares over the then-market price of the shares.

Insider Dealing

The Irish Takeover Rules also provide that no person, other than the bidder, who is privy to confidential price-sensitive information concerning an offer made in respect of the acquisition of a company (or a class of securities) or a contemplated offer shall deal in relevant securities of the target during the period from the time at which such person first has reason to suppose that such an offer, or an approach with a view to such an offer being made, is contemplated to the time of (i) the announcement of such offer or approach; or (ii) the termination of discussions relating to such offer, whichever is earlier.

Corporate Governance

Under Irish law and the Proposed Constitution, the authority for the overall management of Trinseo PLC is vested in the Trinseo PLC Board. The Trinseo PLC Board may delegate any of its powers on such terms as it thinks fit in accordance with the Proposed Constitution and Irish law, although, the Trinseo PLC Board will remain responsible, as a matter of Irish law, for the proper management of the affairs of Trinseo PLC. The directors must ensure that any delegation is and remains appropriate and that an adequate system of control and supervision is in place.

The Trinseo PLC Board will have a standing audit committee, compensation committee, and nominating and governance committee. It is also the intention of Trinseo PLC to assume Trinseo S.A.'s existing code of business conduct and insider trading policy and to adopt governance guidelines in accordance with Irish law and the NYSE.

Directors

Number of Directors

The Proposed Constitution provides that the number of directors will be as the Trinseo PLC board may determine from time to time, at its discretion, but which shall not be less than three. Immediately following the completion of the Merger there will be the same number of directors on the Trinseo PLC Board that sit on the board of Trinseo S.A.

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Appointment of Directors

Directors are elected by ordinary resolution at general meetings, provided that, if there is a contested election (as provided for in the Proposed Constitution), each of the nominees shall be voted upon as a separate resolution and the nominees who shall be elected as directors shall be only those nominees (in number equal to the number of available positions) who receive the highest number of votes of all nominees in favor of their election or re-election.

Under the Proposed Constitution, shareholders have further notification requirements in addition to what is required under Irish law in order to bring a resolution before a meeting of shareholders. For further detail, see the section captioned "Comparison of Rights of Shareholders and Governance under the Articles to the Proposed Constitution—Proposing Resolutions at a General Meeting", beginning on page 49.

Election of Directors

Under the Proposed Constitution, starting with the annual general meeting to be held in 2022, any Director whose term expires at an annual general meeting shall stand for re-election at the annual general meeting. Notwithstanding that a Director might not be re-elected at a general meeting, such Director shall nevertheless hold office until the conclusion of that meeting.

Removal of Directors and Vacancies

Under Irish law and the Proposed Constitution, Trinseo PLC's shareholders have the power to remove a director without cause by simple majority resolution. At least 28 clear days' notice of the resolution is given to Trinseo PLC and the shareholder(s) comply with the relevant procedural requirements.

The power of removal is without prejudice to any claim for damages for breach of contract (e.g., employment contract) which the director may have against Trinseo PLC in respect of his or her removal.

Under Irish law, one or more shareholders representing at least 10% of the paid-up share capital of Trinseo PLC carrying voting rights have the right to requisition the holding of an extraordinary general meeting at which such a resolution to remove a director (and appoint a replacement) may be proposed.

The Proposed Constitution provides that vacancies in the board of directors may be filled by the Trinseo PLC Board.

Duration; Dissolution; Rights upon Liquidation

The duration of Trinseo PLC will be unlimited. Trinseo PLC may be dissolved and wound up at any time by way of a shareholders' voluntary winding up or a creditors' winding up. In the case of a shareholders' voluntary winding up, a special resolution of shareholders is required. Trinseo PLC may also be dissolved by way of court order on the application of a creditor, or by the Companies Registration Office as an enforcement measure if it has failed to file certain returns. Trinseo PLC may also be dissolved by the Director of Corporate Enforcement in Ireland where our affairs have been investigated by an inspector and it appears from the report or any information obtained by the Director of Corporate Enforcement that Trinseo PLC should be wound up.

Under the Proposed Constitution, if Trinseo PLC is wound up and the assets available for distribution among the shareholders of Trinseo PLC are insufficient to repay the whole of the paid-up or credited as paid-up share capital, those assets are required to be distributed so that, as nearly as may be, the losses are borne by the shareholders of Trinseo PLC in proportion to the capital paid-up or credited as paid-up at the commencement of the winding up on the shares in Trinseo PLC held by them respectively. If in a winding-up the assets available for distribution among the Trinseo PLC shareholders are more than sufficient to repay the whole of the share capital paid-up or credited as paid- up at the commencement of the winding-up, the excess is required to be distributed among the shareholders in proportion to the capital at the commencement of the winding-up paid- up or credited as paid-up on the said Trinseo PLC shares held by them respectively. The position described above is subject to any special terms and conditions applying to any class of shares.

No Liability for Further Calls or Assessments

The shares to be issued in connection with the Merger will be duly and validly issued and fully paid and non-assessable.

Transfer and Registration of Shares

Trinseo PLC will maintain a share register or otherwise cause a share register to be maintained. The registration in that register will be used to determine which Trinseo PLC shareholders are entitled to vote at meetings of Trinseo PLC shareholders. A Trinseo PLC shareholder who holds shares beneficially will not be the holder of record of such shares. Instead, the depository or other nominee will be the holder of record of those shares.

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Accordingly, a transfer of shares from a person who holds such shares beneficially to a person who also holds such shares beneficially through a depository or other nominee will not be registered in Trinseo PLC's official share register, as the depository or other nominee will remain the record holder of any such shares.

Under the Proposed Constitution, subject to the Irish Companies Act, certificated shares may be transferred upon surrender for cancellation of the share certificate(s) for the shares in question along with an instrument of transfer, duly executed, with such proof of authenticity of the signature as Trinseo PLC or its agents may reasonably require.

A written instrument of transfer is required under Irish law in order to register on Trinseo PLC's official share register any transfer of shares (i) from a person who holds such shares directly to any other person; (ii) from a person who holds such shares beneficially to a person who will hold such shares directly; or (iii) from a person who holds such shares beneficially to another person who will hold such shares beneficially where the transfer involves a change in the depository or other nominee that is the record owner of the transferred shares. An instrument of transfer is also required for a shareholder who directly holds shares to transfer those shares into his or her own broker account (or vice versa). Such instruments of transfer may give rise to Irish stamp duty, which must be paid prior to registration of the transfer on Trinseo PLC's official Irish share register. However, a shareholder who directly holds shares may transfer those shares into his or her own broker account (or vice versa) and this should not give rise to Irish stamp duty provided there is no change in the ultimate beneficial ownership of the shares as a result of the transfer and the transfer is not made in contemplation of a sale of the shares.

Any transfer of shares in Trinseo PLC that is subject to Irish stamp duty will not be registered in the name of the transferee unless an instrument of transfer is duly stamped and provided to the Trinseo PLC transfer agent. Trinseo PLC, in its absolute discretion and insofar as the Irish Companies Act or any other applicable law permits, may, or may provide that a subsidiary of Trinseo PLC will, pay Irish stamp duty arising on a transfer of shares in Trinseo PLC on behalf of the transferee of such shares. If stamp duty resulting from the transfer of shares in Trinseo PLC which would otherwise be payable by the transferee is paid by Trinseo PLC or any of its subsidiaries on behalf of the transferee, then in those circumstances, Trinseo PLC will, on its behalf or on behalf of its subsidiary (as the case may be), be entitled to (i) seek reimbursement of the stamp duty from the transferee; (ii) set-off the stamp duty against any dividends payable to the transferee of those shares; and (iii) to the extent permitted by law claim a first and permanent lien on the shares on which stamp duty has been paid by Trinseo PLC or its subsidiary for the amount of stamp duty paid. Trinseo PLC's lien shall extend to all dividends paid on those shares. Parties to a share transfer may assume that any Irish stamp duty arising in respect of a transaction in Trinseo PLC shares has been paid unless one or both of such parties is otherwise notified by Trinseo PLC.

The Proposed Constitution delegates to Trinseo PLC's secretary, any assistant secretary or a relevant authorized delegate the authority to execute an instrument of transfer on behalf of a transferor.

To help ensure that our official share register is regularly updated to reflect trading of shares in Trinseo PLC occurring through electronic systems, Trinseo PLC intends to regularly produce such instruments of transfer as may be required to effect any transfers of registered interests in shares. These may involve transactions for which it pays stamp duty, subject to the reimbursement and set-off rights described above. In the event that Trinseo PLC notifies one or both of the parties to a share transfer that it believes stamp duty is required to be paid in connection with such transfer and that it will not pay such stamp duty, the parties may either themselves arrange for the execution of the required instrument of transfer (and may request a form of instrument of transfer from Trinseo PLC for this purpose) or request that Trinseo PLC execute an instrument of transfer on behalf of the transferring party in a form determined by Trinseo PLC. In either event, if the parties to the share transfer have the instrument of transfer duly stamped (to the extent required) and then provide it to Trinseo PLC's transfer agent, the transferee named therein will be registered as the registered holder of the relevant shares on Trinseo PLC's official share register (subject to the matters described below).

The registration of transfers may be suspended by our directors at such times and for such period, not exceeding in the whole 30 days in each year, as our directors may from time to time determine.

Indemnification of Directors and Officers

Subject to exceptions, Irish law does not permit a company to exempt a director or certain officers from, or indemnify a director against, liability in connection with any negligence, default, breach of duty or breach of trust by a director in relation to the company.

The exceptions allow a company to: (a) purchase and maintain directors and officers insurance against any liability attaching in connection with any negligence, default, breach of duty or breach of trust owed to the company; and (b) indemnify a director or such other officer against any liability incurred in defending proceedings, whether civil or criminal: (i) in which judgment is given in his or her favor or in which he or she is acquitted; or (ii) in respect of which an Irish court grants him or her relief from any such liability on the grounds that he or she acted honestly and reasonably and that, having regard to all the circumstances of the case, he or she ought fairly to be excused for the wrong concerned.

The Proposed Constitution includes a provision which entitles every director to be indemnified by Trinseo PLC (including by funding any expenditure incurred or to be incurred by him or her) against any loss or liability incurred in his or her capacity as a director to the fullest extent permitted by law. The Proposed Constitution provides that where a person is so indemnified, such indemnity may extend to all costs, losses, expenses and liabilities incurred by him or her. Any funds provided in compliance with Irish law to a director to meet any

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expenditure incurred by him or her in connection with defending himself or in an investigation of any negligence, default, breach of duty or breach of trust by him or her or otherwise, must be given on the basis of an undertaking from the director that the funds will be repaid if he or she is convicted, or judgment is given against him or her.

The Proposed Constitution also provides the Trinseo PLC Board with authority to purchase and maintain insurance at the expense of Trinseo PLC for the benefit of any person who is, or was at any time, a director or other officer or employee of the company or any associated company.

In addition to the provisions of the Proposed Constitution, it is common for a public limited company to enter into separate a deed of indemnity with a director or officer which essentially indemnifies the director or officer against claims brought by third parties to the fullest extent permitted under Irish law. Trinseo PLC intends to enter into such deeds of indemnity with each of its directors and officers. In addition, given the director indemnification limitations arising under Irish law, it is expected Trinseo PLC will procure that one or more of its subsidiaries will enter into indemnification agreements with each of the Trinseo PLC directors indemnifying them in respect of any liability incurred by them while acting as a director of Trinseo PLC.

Limitation on Director Liability

Subject to exceptions, as described above, Irish law does not permit a company to exempt any director or certain officers from any liability arising from negligence, default, breach of duty or breach of trust against the company. One of the exceptions is that an Irish company is permitted to purchase and maintain insurance for a director or executive officer of the company against any such liability.

Separately, in proceedings where negligence, default, breach of duty or breach of trust against a director has or may be established (or in anticipation of any such proceedings), an Irish court has the power to grant a director or other officer relief from liability on the grounds that he or she acted honestly and reasonably and that, having regard to all the circumstances of the case, he or she ought fairly to be excused for the wrong concerned.

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PROPOSAL 5

Proposal 5—Distributable Profits Proposal

Under Irish law, Trinseo PLC may only pay dividends, make other distributions, or make share repurchases and redemptions from "distributable profits" shown in Trinseo PLC's unconsolidated financial statements prepared in accordance with the Irish Companies Act and filed with the Irish Companies Registration Office.

"Distributable profits" are the accumulated realized profits of Trinseo PLC that have not previously been utilized in a distribution or capitalization less its accumulated realized losses that have not previously been written off in a reduction or reorganization of capital, and include reserves created by way of a reduction of capital.

In addition, under Irish law, no dividend, distribution or share repurchase, or redemption may be paid, made or effected by Trinseo PLC unless the net assets of Trinseo PLC are equal to, or exceed, the aggregate of Trinseo PLC's called-up share capital plus its undistributable reserves and the relevant transaction does not reduce Trinseo PLC's net assets below such aggregate. "Undistributable reserves" include the undenominated capital, the capital redemption reserve fund and the amount by which Trinseo PLC's accumulated unrealized profits that have not previously been utilized by any capitalization exceed Trinseo PLC's accumulated unrealized losses that have not previously been written off in a reduction or reorganization of capital.

Immediately following the Merger, the unconsolidated balance sheet of Trinseo PLC will not contain any distributable profits and "shareholders' equity" on such balance sheet will be comprised entirely of "issued share capital" (equal to the aggregate nominal value of Trinseo PLC shares allotted and issued pursuant to the Merger) and "share premium" (equal to the amount paid-up on such Trinseo PLC shares in excess of the nominal value). You are being asked to approve the Distributable Profits Proposal, to enable, subject to the effectiveness of the Merger, the creation of

distributable profits of Trinseo PLC under Irish law by reducing the entire share premium of Trinseo PLC (or such lesser amount as may be approved by the Trinseo PLC Board) resulting from the allotment and issue of Trinseo PLC shares pursuant to the Merger, such that the reserve resulting from the cancellation of such share premium will be treated as distributable profits.

In addition to the approval of Trinseo S.A. shareholders, the Distributable Profits Proposal also requires the passing of a special resolution by the shareholders of Trinseo PLC (which will be passed by the existing shareholders prior to the Merger) and the approval of the Irish High Court. If the Distributable Profits Proposal is approved by Trinseo S.A. shareholders, Trinseo PLC intends to seek the approval of the Irish High Court for the Distributable Profits Proposal as soon as practicable following the Effective Date. Although Trinseo S.A. is not aware of any reason why the Irish High Court would not approve the Distributable Profits Proposal, such approval is a matter of judicial discretion and there is no guarantee that such approval will be forthcoming.

The Trinseo S.A. Board strongly recommends that shareholders vote for the Distributable Profits Proposal, to increase the likelihood that the proposal will be approved by the Irish High Court. If the Distributable Profits Proposal is not approved by Trinseo S.A. shareholders and the Irish High Court, Trinseo PLC will not be able to pay dividends, make other distributions or effect share repurchases and redemptions until such time as it has otherwise generated sufficient distributable profits from its operational activities following the Merger. However, passage of the Distributable Profits Proposal is not a condition to the Merger.

The Distributable Profits Proposal requires the approval of a majority of the shares represented in person or by proxy at the General Meeting. Broker non-votes will have no effect on the outcome of this proposal.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE "FOR"
APPROVAL OF THE CREATION OF DISTRIBUTABLE RESERVES.

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PROPOSAL 6

Proposal 6—Election of Directors

Trinseo's Board consists of twelve directors with one-year terms expiring in 2021. Each of the directors are elected for an annual term to serve until the next annual general meeting.

The persons named in the enclosed proxy will vote to elect K'Lynne Johnson, Joseph Alvarado, Frank Bozich, Jeffrey Cote, Pierre-Marie De Leener, Sandra Beach Lin, Jeanmarie Desmond, Matthew Farrell, Philip Martens, Donald Misheff, Henri Steinmetz and Mark Tomkins as directors unless the Proxy is marked otherwise. Each of the nominees has indicated his or her willingness to serve, if elected. However, if a nominee should be unable to serve, the ordinary shares represented by proxies may be voted for a substitute nominee designated by the Board. Management has no reason to believe that any of the above-mentioned persons will not serve his or her term as a director.

Our Board currently consists of 12 directors, the maximum number allowed under our Articles. If shareholders approve the Board Increase Proposal at the General Meeting, our Board size will be increased to 13 directors.

Half of our current directors have served on the Board for less than 4 years, while the average term of service of our directors is approximately 3.5 years.

We are committed to ongoing and regular board refreshment and succession planning. In 2020 two of our longest-tenured directors announced their retirement, and the Board appointed two new independent directors, Ms. Desmond and Mr. Farrell, to fill the vacancies. During 2020 the Board also named K'Lynne Johnson as its new Chair and appointed new chairs of its audit committee and nominating and corporate governance committee.

2021 Director Nominees

The individuals listed below have been nominated and are standing for election at this year's General Meeting. If elected, they will hold office until our 2022 annual general meeting of shareholders and until their successors are duly elected and qualified. Each of the nominees in this proposal was previously elected to the Board by shareholders, except Ms. Desmond and Mr. Farrell who were appointed by the Board to fill vacancies. Each of the nominees will cease to be directors if their respective appointments are not approved by a majority of the votes cast by our shareholders.

Director Nominee Skills

The following table highlights certain skills, knowledge and experience held by each current Director nominee. A particular Director may possess other skills, knowledge or experience even though they are not indicated below.

Director Nominee

Served Since

Chemicals Industry Experience

Manufacturing/ Related Industry Experience

Chief Executive Experience

Accounting and Financial Experience

Public Company Board Experience

K'Lynne Johnson

2017

X

X

X

Joseph Alvarado

2017

​

X

X

X

X

Frank Bozich

2018

X

X

X

X

Jeffrey J. Cote

2014

​

X

X

X

X

Pierre-Marie De Leener

2014

X

X

X

Jeanmarie Desmond

2020

X

X

​

X

​

Matthew Farrell

2020

X

X

X

X

X

Sandra Beach Lin

2019

X

X

X

​

X

Philip R. Martens

2016

X

X

X

Donald T. Misheff

2015

​

X

​

X

X

Henri Steinmetz

2017

X

X

Mark Tomkins

2019

X

​

​

X

X

Victoria Brifo (1)

—

X

X

​

​

​

​

​

​

​

​

​

​

​

​

​

(1)

Shareholders may vote to elect Ms. Brifo in Proposal 7, which is subject to approval of the amendment to the Company's Articles in Proposal 2.

Board Commitment to Diversity

We seek nominees from diverse backgrounds with established strong professional reputations, sophistication, business acumen and experience in the global materials, chemical and related manufacturing industries. We also seek nominees with experience in substantive areas that are important to our business such as chemical industry expertise, international operations; accounting, finance and capital structure; strategic planning and

operational leadership of complex organizations; human resources and development practices; and innovation. In addition, we believe that our nominees should possess the professional and personal qualifications necessary for board service, and we have highlighted particularly noteworthy attributes in each of the biographies of our directors and our nominees below. Twenty-five percent of our directors are women, and one of our directors self-identifies as a member of an underrepresented minority group

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PROPOSAL 6

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(meaning an individual who self-identifies as Black or African American, Hispanic or Latinx, Asian, Native American or Alaska

Native, Native Hawaiian or Pacific Islander). Two of our directors are non-U.S. citizens and one director maintains dual citizenship.

The election of each director requires the approval of a majority of the shares represented in person or by proxy at the General Meeting. Broker non-votes will have no effect on the outcome of this proposal.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE "FOR"
THE ELECTION OF EACH OF THE NOMINEES AS DIRECTOR.

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PROPOSAL 6

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2021 Director Nominees

	​	K'lynne Johnson Age: 52 Director Since: March 2017 Committee Membership: • Compensation and Talent Development (Chair) • Nominating & Corporate Governance

Professional Experience:

Ms. Johnson served as President and Chief Executive Officer of Elevance Renewable Sciences Inc., a specialty chemicals company, from 2007 to 2015, and as Chairwoman from 2015 to 2016. Ms. Johnson joined Elevance after over 20 years' experience working within the oil and petrochemicals industry for Amoco Corporation and BP p.l.c. (joining BP after its merger with Amoco in 1998). During this time she held both operational and functional roles, culminating in her role as Senior Vice President of Global Derivatives within BP's global Innovene business, which included P&L accountability for multiple global commodity and specialty chemicals businesses. Ms. Johnson also served as director of TPC Group, a manufacturer of products derived from petrochemical raw materials, from 2011 to 2012 before the company was taken private.

Education:

Ms. Johnson graduated from Brigham Young University with a degree in Management and Organizational Behavior (M.O.B.) and a B.S. in Psychology.

Other Public Company Directorships:

Current Directorships—
FMC Corporation (NYSE: FMC) since 2013

Director Qualifications:

Ms. Johnson brings to our Board valuable experience in operational leadership and chemical industry and technological expertise.

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PROPOSAL 6

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	​	Joseph Alvarado Age: 68 Director Since: March 2017 Committee Membership: • Audit • Environmental, Health, Safety, Sustainability & Public Policy

Professional Experience:

Mr. Alvarado served as Chief Executive Officer of Commercial Metals Company (NYSE: CMC), a global manufacturer, recycler and marketer of steel and other metals, from September 2011 until September 2017, and as Chairman of CMC's board of directors from January 2013 until January 2018. He joined CMC in April 2010 as Executive Vice President and Chief Operating Officer, was named President and Chief Operating Officer in April 2011, and became President and Chief Executive Officer in September 2011 until his retirement. Prior to joining CMC, he was President and Chief Operating Officer of Lone Star Technologies, Inc. from 2004 to 2007. In June 2007, following the acquisition of Lone Star Technologies, Inc. by United States Steel Corporation, Mr. Alvarado was named President of U.S. Steel Tubular Products, Inc., a division of United States Steel Corporation, a position he held until March 2009. Mr. Alvarado began his career at Inland Steel Company in 1976 and spent 21 years with the company in roles of increasing responsibility. He then served in executive roles with Birmingham Steel Corporation and Ispat North America Inc. until joining Lone Star Technologies.

Education:

Mr. Alvarado has an MBA from Cornell University and a B.A. degree in Economics from University of Notre Dame.

Other Public Company Directorships:

Current Directorships—
Kennametal Inc. (NYSE: KMT) since January 2018
Arcosa, Inc. (NYSE: ACA) since November 2018
PNC Financial Services Group Inc. (NYSE: PNC) since January 2019

Past Directorships—
Commercial Metals Company (NYSE: CMC) from 2013 to January 2018
Spectra Energy Corp (NYSE: SE) from 2011 until February 2017

Director Qualifications:

Mr. Alvarado brings years of experience in a cyclical commodities-driven industry and significant perspective on global manufacturing operations and strategic planning.

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	​	Frank A. Bozich Age: 60 Director Since: June 2019 Committee Membership: • Environmental, Health, Safety, Sustainability & Public Policy

Professional Experience:

Mr. Bozich became the Company's President and Chief Executive Officer in March 2019. From May 2013 until February 2019, Mr. Bozich had been the President and Chief Executive Officer at the SI Group, Inc., a leading global developer and manufacturer of phenolic resins and chemicals used in the production of antioxidants, engineering plastics, fuels and lubes, rubber and pharmaceutical ingredients. Prior to SI Group Inc., Mr. Bozich held several executive management positions at BASF Corporation, a multi-national chemicals and manufacturing corporation, including President of BASF's Catalysts Division from 2010 to 2013, Group Vice President of Precious and Base Metal Service, and Group Vice President of the Integration Management Office. Prior to BASF, Mr. Bozich was Group Vice President, Enterprise Technologies and Ventures at Engelhard Corporation, which was acquired by BASF in 2006. He has also held leadership positions at Rohm and Haas; Croda Adhesives, Inc.; and Apex Adhesives, which he founded in 1986.

Education:

Mr. Bozich holds a bachelor's degree in Chemistry and a master's degree in Business Administration from the University of Chicago, as well as a master's degree in Chemistry from the University of Illinois.

Other Public Company Directorships:

Current Directorships—
OGE Energy Corp (NYSE: OGE) since February 2016

Director Qualifications:

Mr. Bozich is an accomplished CEO known for his strong personal leadership and track record of driving business growth and corporate transformation. His breadth of experience in leading chemical businesses in diverse and dynamic global markets is well-suited for the Company's strategic priorities.

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PROPOSAL 6

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	​	Jeffrey J. Cote Age: 54 Director Since: May 2014 Committee Membership: • Audit • Compensation and Talent Development

Professional Experience:

Mr. Cote has served as the Chief Executive Officer and President of Sensata Technologies Holding plc (NYSE: ST) since March 2020. Prior to his appointment as CEO, Mr. Cote served as President and as Chief Operating Officer of Sensata since July 2012 and as Executive Vice President of its Global Sensing Solutions business since November 2015. He joined Sensata as Senior Vice President and Chief Financial Officer in January 2007 and was appointed Executive Vice President in July 2007. From March 2005 to December 2006, Mr. Cote was Chief Operating Officer of the law firm Ropes & Gray. From January 2000 to March 2005, Mr. Cote was Chief Operating, Financial and Administrative Officer of Digitas. Previously he worked for Ernst & Young LLP from 1989 until 1997. Mr. Cote is a certified public accountant.

Education:

Mr. Cote received a B.A. degree in Business Administration and a Master of Accounting from Florida Atlantic University.

Other Public Company Directorships:

Current Directorships—
Sensata Technologies Holding plc (NYSE: ST) since March 2020

Director Qualifications:

Mr. Cote brings significant management, financial and accounting experience to our Board.

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	​	Pierre-Marie De Leener Age: 63 Director Since: May 2014 Committee Membership: • Audit • Environmental, Health, Safety, Sustainability & Public Policy

Professional Experience:

Mr. De Leener served as interim CEO of Braas Monier Building Group SA from January 2016 to November 2016 and as Chairman of its Board of Directors from June 2014 to March 2017. Prior to that, he served as Executive Vice President for PPG Industries, Inc. from July 2010 until December 2012. From June 2008 until August 2011, Mr. De Leener also served as President of PPG Europe S.A. and as Chief Executive Officer of SigmaKalon Group from 1998 until January 2008.

Education:

Mr. De Leener received a B.S. degree in Economics and Philosophy and a Master of Chemical Engineering degree from Catholic University of Louvain, Belgium.

Other Public Company Directorships:

None

Director Qualifications:

Mr. De Leener brings valuable executive management and chemical industry experience to our Board.

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PROPOSAL 6

	​	Jeanmarie Desmond Age: 54 Director Since: October 2020 Committee Membership: • Audit • Compensation and Talent Development

Professional Experience:

Ms. Desmond is the former Executive Vice President and Chief Financial Officer of DuPont de Nemours, Inc. and has previously served as Vice President and Co-Controller for DowDuPont and as finance leader for the Specialty Products division following the merger of DuPont with Dow Chemical. Ms. Desmond served in various leadership roles within DuPont in her 30-year career with the company. She also serves on the board and is treasurer of Delaware Prosperity Partnership, a public-private partnership overseeing economic development in Delaware.

Education:

Ms. Desmond received a B.S. in Accounting from Mt. St. Mary's University and is a certified public accountant (inactive).

Other Public Company Directorships:

Current Directorships—
IPG Photogenics Corporation (Nasdaq: IPGP) since 2021

Director Qualifications:

Ms. Desmond brings substantial finance and accounting experience and extensive experience in the chemicals industry to our Board.

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	​	Matthew Farrell Age: 64 Director Since: November 2020 Committee Membership: • Compensation and Talent Development • Nominating and Corporate Governance

Professional Experience:

Mr. Farrell is the Chairman, President and Chief Executive Officer of Church & Dwight Co. Inc. ("Church & Dwight"), serving since 2016 and as Chairman since 2019. Mr. Farrell served as Executive Vice President, Chief Financial Officer and Chief Operating Officer at Church & Dwight since 2014, and as Chief Financial Officer since 2006. Prior to that, Mr. Farrell served as Chief Financial Officer of Alpharma Inc., as Vice President, Investor Relations & Communications at Ingersoll-Rand Ltd., and in various senior financial positions at AlliedSignal Inc. Mr. Farrell began his career with KPMG Peat Marwick LLP, where he was an audit partner.

Education:

Mr. Farrell received a B.S. degree from Manhattan College and is a certified public accountant (inactive).

Other Public Company Directorships:

Current Directorships—
Church & Dwight Co. Inc. (NYSE: CHD) since 2019
Lydall Co., Inc. (NYSE: LDL) since 2003*

Director Qualifications:

Mr. Farrell brings to our Board his experience as a chief executive officer, substantial financial and audit expertise and experience in the chemicals, industrial goods and consumer products industries.

   

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*

In September 2020, Mr. Farrell informed the Lydall board of directors of his intention not to stand for reelection as a director at Lydall's next annual meeting of shareholders, to be held on April 20, 2021.

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	​	Sandra Beach Lin Age: 63 Director Since: November 2019 Committee Membership: • Compensation and Talent Development • Nominating & Corporate Governance

Professional Experience:

From 2010 to 2011, Ms. Beach Lin was President and Chief Executive Officer of Calisolar, Inc., a manufacturer of solar silicon and multicrystalline solar cells. Prior to joining Calisolar, she was Executive Vice President, then Corporate Executive Vice President, at Celanese Corporation, a global technology and specialty materials company, from 2007 to 2010. Ms. Beach Lin joined Avery Dennison Corporation, a global leader in pressure-sensitive adhesives technology as Group Vice President from 2005 to 2007. Prior to joining Avery Dennison, from 2002 to 2005, she was President, Alcoa Closure Systems International, a division of Alcoa Incorporated, a global aluminum leader. From 1994 to 2001, Ms. Beach Lin held various executive positions at Honeywell International.

Education:

Ms. Beach Lin graduated with a BBA in General Management from the University of Toledo and has an MBA in Marketing and Policy and Control from the University of Michigan.

Other Public Company Directorships:

Current Directorships—
American Electric Power (NYSE: AEP) since 2012
Avient Corp. (NYSE: AVNT) since 2013

Past Directorships—
WESCO International (NYSE: WCC) from 2002 to 2019

Director Qualifications:

Ms. Beach Lin brings to our Board her experience as a chief executive officer and extensive experience in the global specialty chemicals industry.

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	​	Philip R. Martens Age: 61 Director Since: September 2016 Committee Membership: • Compensation • Nominating & Corporate Governance (Chair)

Professional Experience:

From February 2011 to April 2015, Mr. Martens served as President and Chief Executive Officer of Novelis, Inc., a leader in aluminum rolled products and can recycling with worldwide operations. He joined Novelis as President and Chief Operating Officer in April 2009. Prior to his employment with Novelis, Mr. Martens served as Senior Vice President of light vehicle systems for ArvinMeritor Inc., a distributor for engine and transmission parts and President and Chief Executive Officer designate of Arvin Innovation, a leading global provider of dynamic motion and control automotive systems. From 1987 to 2005, Mr. Martens held various product development and engineering roles at Ford Motor Company, including his most recent role as a Group Vice President of product creation from 2003 to 2005.

Education:

Mr. Martens has an MBA from University of Michigan and received his B.S. degree in mechanical engineering from Virginia Polytechnic Institute.

Other Public Company Directorships:

Current Directorships—
Graphic Packaging Holding Company (NYSE: GPK) since 2013

Past Directorships—
Plexus Corporation (NASDAQ: PLXS) from 2010 until February 2017

Director Qualifications:

Mr. Martens brings to the Board significant leadership and management experience in global manufacturing operations, along with innovation expertise.

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	​	Donald T. Misheff Age: 64 Director Since: February 2015 Committee Membership: • Audit • Nominating & Corporate Governance

Professional Experience:

Mr. Misheff served as managing partner from 2003 until his retirement in 2011 of the Northeast Ohio offices of Ernst & Young LLP, a public accounting firm. As the managing partner, Mr. Misheff advised many of the region's largest companies on financial and corporate governance issues. He began his career with Ernst & Young LLP in 1978 as part of the audit staff and later joined the tax practice, specializing in accounting/financial reporting for income taxes, purchase accounting, and mergers and acquisitions. He has more than 30 years of experience performing, reviewing, and overseeing the audits of financial statements of a wide range of public companies.

Education:

Mr. Misheff graduated from the University of Akron with a B.S. in Accounting.

Other Public Company Directorships:

Current Directorships—
TimkenSteel Corporation (NYSE: TMST) since 2014
First Energy Corp. (NYSE: FE) since 2012

Director Qualifications:

Mr. Misheff brings extensive financial, accounting and public company corporate governance experience to our Board.

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	​	Henri Steinmetz Age: 64 Director Since: November 2017 Committee Membership: • Nominating & Corporate Governance • Environmental, Health, Safety, Sustainability & Public Policy

Professional Experience:

From 2016 to 2018, Mr. Steinmetz served as Chief Executive Officer of the Ceramtec Group, a global supplier of advanced ceramics. From 2009 to 2016, Mr. Steinmetz was Executive Director and Chief Executive Officer of Ruetgers N.V., Europe's leading manufacturer of chemical raw materials made from coal tar. Prior to joining Ruetgers, Mr. Steinmetz was President of Sulzer Metco, a worldwide technology leader in coating materials, from 2004 to 2008, and was an Executive Vice President at Great Lakes Chemical Corporation from 2000 to 2004.

Education:

Mr. Steinmetz graduated with a M.S. in metallurgy from the Technical University Clausthal, Germany and has an MBA from INSEAD Fontainebleau, France.

Other Public Company Directorships:

None

Director Qualifications:

Mr. Steinmetz brings significant global chief executive officer experience and decades of chemical industry experience to our Board.

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PROPOSAL 6

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	​	Mark Tomkins Age: 65 Director Since: November 2019 Committee Membership: • Audit (Chair) • Environmental, Health, Safety, Sustainability & Public Policy

Professional Experience:

From 2005 to 2006, Mr. Tomkins was Senior Vice President and Chief Financial Officer of Innovene, at the time, a leading petrochemical and polymers company. Prior to joining Innovene, Mr. Tomkins was Senior Vice President, Chief Financial Officer and Treasurer of Vulcan Materials, a building materials and chemical company, from 2001 to 2005. He joined Great Lakes Chemical Corp., a chemical research, production, sales and distribution company as Senior Vice President and Chief Financial Officer from 1998 to 2001. Prior to Great Lakes Chemical, Mr. Tomkins was Vice President of Finance and Business Development for Polymers and Vice President of Finance and Business Development for Electronic Materials at Allied Signal (now Honeywell International). Mr. Tomkins' previous experience includes service as a director of CVR Energy, Inc., a publicly traded company primarily engaged in petroleum refining and nitrogen fertilizer manufacturing, from 2007 to 2012, as well as a director of private companies in the energy and plastics sectors.

Education:

Mr. Tomkins graduated with a B.S. in Finance and Quantitative Management, has an MBA from Eastern Illinois University and is a certified public accountant.

Other Public Company Directorships:

Current Directorships—
Terminix Global Holdings (NYSE: TMX) since 2015
WR Grace & Co. (NYSE: GRA) since 2006

Director Qualifications:

Mr. Tomkins brings significant financial, accounting and management expertise, along with extensive experience on other public and private company boards to Trinseo's Board.

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PROPOSAL 7

Proposal 7—Election of Director

Conditioned upon shareholder approval of Proposal 2, the Board has nominated Victoria Brifo as its nominee for Director. The persons named in the enclosed proxy will vote to elect Ms. Brifo as director unless the Proxy is marked otherwise. Ms. Brifo has indicated her willingness to serve, if elected, and should she be unable to serve, the ordinary shares represented by proxies may be voted for a substitute nominee designated by the Board. Management has no reason to believe that she will not serve her term as a director. If elected, Ms. Brifo will hold office until our 2022 annual general meeting of shareholders and until her successor is duly elected and qualified. Ms. Brifo will not be elected director if her appointment is not approved by a majority of the shares represented in person or by proxy at the General Meeting. Broker non-votes will have no effect on the outcome of this proposal.

Victoria Brifo

Age: 52

Professional Experience:

Victoria Brifo is Senior Vice President and Chief Human Resources Officer at Air Products and Chemicals, Inc. (NYSE: APD). She is responsible for leading all aspects of the company's Human Resources (HR) organization, including HR Operations, Diversity and Inclusion, Talent Management, and Compensation and Benefits, as well as Global Health and Wellness, and Corporate Aviation and Corporate Transportation. Ms. Brifo has been with Air Products since 2001, starting as a production site leader and progressing through several plant leadership positions before becoming Global Diversity Director in 2005. In 2008 she was named Global Manager of Electronics Operations and moved to the Merchant Gases group in 2011 to lead the Global Generated Gases business. In 2014 Ms. Brifo assumed the role of Global Transformation Leader for Industrial Gases. She was subsequently appointed Vice President, Global Gases, followed by Vice President, Equipment Sales, Plant Support and Central Procurement. Prior to joining Air Products, Ms. Brifo worked at LyondellBasell and Amoco Production Company.

Education:

Ms. Brifo holds degrees in chemical engineering and political science from the Massachusetts Institute of Technology.

Other Public Company Directorships:

None

Director Qualifications:

Ms. Brifo brings significant experience in the chemicals and manufacturing industry, as well as leadership, management and human resources expertise to our board of directors.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE "FOR"
THE ELECTION OF VICTORIA BRIFO AS DIRECTOR.

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CORPORATE GOVERNANCE

Corporate Governance

Board Nominees.    Under its charter, our nominating and corporate governance committee is responsible for recommending to the Board candidates to stand for election to the Board at the Company's annual general meeting of shareholders and for recommending candidates to fill vacancies on the Board that may occur between annual general meetings. It is the policy of the Board that directors should possess the highest personal and professional ethics, integrity and values. Board members are expected to become and remain informed about the Company, its business and its industry and rigorously prepare for, attend and participate in all Board and applicable committee meetings. The committee evaluates each individual in the context of the Board as a whole, with the objective of recommending a group that can best perpetuate the success of our business and represent shareholders' interests through the exercise of sound judgment using its diversity of experience. In addition, the Board considers, in light of our business and Board composition, each director nominee's experience, qualifications, attributes and skills that are identified in the biographical information contained under Proposal 6 and Proposal 7.

The nominating and corporate governance committee considers properly submitted recommendations for candidates to the Board from shareholders. Any shareholder may submit in writing nominations of persons for consideration for each shareholder meeting at which directors are to be elected by not later than the 90th calendar day nor earlier than the 120th calendar day before the date of the annual general meeting. Any shareholder recommendations for consideration by the Board should include the candidate's name, biographical information, information regarding any relationships between the candidate and the shareholder within the last three years, a statement of recommendation of the candidate from the shareholder, a description of our shares beneficially owned by the shareholder, a description of all arrangements between the candidate and the recommending shareholder and any other person pursuant to which the candidate is being recommended, a written indication of the candidate's willingness to serve on the Board, any other information required to be provided under securities laws and regulations, and a written indication to provide such other information as the Board may reasonably request. Recommendations should be sent to Angelo N. Chaclas, Corporate Secretary, Trinseo S.A., 1000 Chesterbrook Boulevard, Suite 300, Berwyn, PA 19312. The Board evaluates candidates for the position of director recommended by shareholders or others in the same manner as candidates from other sources. The Board will determine whether to interview any candidates and may seek additional information about candidates from third-party sources. As part of its ongoing succession planning, the Company seeks to identify potential Board nominees on behalf of the Board that meet the Board's requirements with respect to diversity, experience, skill, and qualifications.

Board Independence.    Our Corporate Governance Guidelines provide that our Board shall consist of such number of directors who are independent as is required and determined in accordance with applicable laws and regulations and requirements of the NYSE. The Board evaluates any relationships of each director and nominee with Trinseo and makes an affirmative determination whether or not such director or nominee is independent. Under our Corporate Governance Guidelines, an "independent" director is one who meets the qualification requirements for being an independent director under applicable laws and the corporate governance listing standards of the NYSE. Our Board reviews any transactions and relationships between each director or any member of his or her immediate family and Trinseo. The purpose of this review is to determine whether there were any such relationships or transactions and, if so, whether they were inconsistent with a determination that the director was independent. The Company maintains a related party transactions policy and conflict of interest policy, as discussed below under "Related Party Transactions." As a result of its review, our Board has affirmatively determined that all of our current directors and nominees, except for our CEO and President, Frank Bozich, are independent under the governance and listing standards of the NYSE.

Diversity and Board Expertise.    We believe that diversity considerations are an important element, among many, when identifying director nominees who will best serve the needs of the Company and the interests of our shareholders. These diversity considerations enable us to provide sound and prudent guidance by developing a Board with a diverse range of talents, ages, skills, character, expertise, professional experiences, and backgrounds.

Risk Oversight.    Risk is inherent in every material business activity that we undertake. Our business exposes us to strategic, credit, market, compliance, operational and reputational risks. To support our corporate goals and objectives, risk appetite, and business and risk strategies, we maintain a governance structure that delineates the responsibilities for risk management activities, and the governance and oversight of those activities, between management and our Board. The Board is committed to strong, independent oversight of management and risk through a governance structure that includes other Board committees. Under our structure, it is management's responsibility to manage risk and bring to the Board's attention risks that are material to Trinseo. The Board has oversight responsibility for the systems established to report and monitor the most significant risks applicable to Trinseo. The Board administers its risk oversight role directly and through its committee structure and the committees' regular reports to the Board at Board

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meetings. The Board divides its risk oversight responsibilities between itself and its committees by having each review or assess key issues or areas of responsibility as follows:

​	​	​
Board of Directors		• Strategic, financial, and execution risks and exposures associated with our annual and multi-year business plans • Acquisitions and divestures • Capital expenditure and budget planning • Major litigation, investigations, and other matters that present material risk to our operations, plans, prospects, or reputation • Review of enterprise risk management including cybersecurity and information security risk oversight
Audit Committee		• Risks associated with financial accounting matters, including financial reporting, accounting, disclosure, and internal controls over financial reporting • Supervision and selection of our external and internal auditors • Our ethics and compliance programs
Compensation Committee		• Risks related to the design of our executive compensation programs, plans, and arrangements • Senior management succession planning
Nominating and Corporate Governance Committee		• Risks related to our governance structures and processes • Director succession planning
Environmental, Health, Safety, Sustainability and Public Policy Committee		• Our environmental, health and safety risk management programs • The alignment of our environmental, health, safety, sustainability, social and public policy program with the Company's business strategy and creation of stakeholder value
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Board Leadership Structure.    Under our Corporate Governance Guidelines, our Board may select a Chair of the Board at any time, who may also be an executive officer of the Company. The Board has chosen to separate the roles of Board Chair and Chief Executive Officer, which the Board believes is currently in the best interest of Trinseo and its shareholders. This structure permits our Chief Executive Officer to devote his attention to leading Trinseo and to executing on our business strategy.

Ms. Johnson is our current non-executive Chair of the Board and has served as a director since 2017. Ms. Johnson brings significant experience as Chair, including, but not limited to: (i) entrepreneurial and senior public company experience; (ii) expertise in environmental, social and governance issues; and (iii) strategic transformation experience. Ms. Johnson has significant experience in the specialty chemical industry and as a public company director. As described above, the Board has determined that Ms. Johnson meets the definition of an independent director under NYSE listing standards. Following the General Meeting, the Board will meet to adjust committee assignments as necessary.

Board Attendance.    We expect our Board members to prepare for, attend and participate in all Board and applicable committee meetings. Our Board held nine meetings in 2020. The audit, compensation, and nominating and corporate governance committees held nine, six and five meetings in 2020, respectively. No Board member attended less than 75% of our Board and committee meetings, as applicable, in 2020.

Due to the travel restrictions and stay-at-home orders in the U.S., Luxembourg and elsewhere during the COVID-19 pandemic, our full Board has not traveled to Luxembourg to attend meetings in person. Like many companies, we continue to hold board meetings via video conference and intend to do so until travel restrictions are lifted, and health and safety concerns have been alleviated.

We do not have a policy for the attendance of our directors at our annual general meeting of shareholders. In 2020 four directors and no shareholders attended our annual general meeting, which was held via teleconference pursuant to guidance from the Grand Duchy of Luxembourg. Under Luxembourg law, we are required to receive notice by the meeting's record date of a shareholder's intention to attend the annual general meeting of shareholders. In 2020 we allowed eligible shareholders to attend the teleconference by registering on our voting website. This year's General Meeting will once again be held via teleconference, using the same registration method for shareholders who wish to attend. We fully intend to resume holding future annual general meetings of shareholders in person, once it is possible for all participants to attend safely.

Executive Sessions.    Our Corporate Governance Guidelines provide that the non-management directors of the Board meet in executive session at least once during each regularly scheduled Board meeting to review matters concerning the relationship of the Board with the management directors and other members of senior management and such other matters as it deems appropriate. Additionally, the Board is required to have least one executive session annually of its independent directors. Ms. Johnson acts as the chair of these executive sessions.

Board Annual Performance Reviews.    Pursuant to our Corporate Governance Guidelines the Board annually conducts a self-evaluation of the Board as a whole. In accordance with the written charters of our audit, compensation and nominating and

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CORPORATE GOVERNANCE

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corporate governance committees, we also evaluate each committee's performance on an annual basis and report to the Board the findings.

Code of Business Conduct.    We have adopted a written Code of Business Conduct applicable to all directors, officers and employees and a written Code of Ethics for Senior Financial Employees, applicable to our Chief Executive Officer, Chief Financial Officer, Treasurer, Principal Accounting Officer, Controller, and all employees performing similar functions. These policies are designed to maintain the integrity of our business and financial reporting. These codes cover, among other things, professional conduct, conflicts of interest, accurate recordkeeping and reporting, public communications and the protection of confidential information, as well as adherence to laws and regulations applicable to the conduct of our business. Copies of these codes can be found under the "Corporate Governance" tab on the Investor Relations section of our website, www.investor.trinseo.com by selecting the "Ethics and Compliance" link and then "supporting policies."

Corporate Governance Guidelines.    We have adopted Corporate Governance Guidelines that outline the Board's governance policies and practices. The current version of our Corporate Governance Guidelines can be found under the "Corporate Governance" tab on the Investor Relations section of our website, www.investor.trinseo.com by selecting the "Ethics and Compliance" link and then "supporting policies."

Communications with Directors.    Shareholders and other interested parties may communicate directly with the Board, the non-management directors or the independent directors as a group, or specified individual directors by writing to such individual or group c/o Corporate Secretary, Trinseo S.A., 1000 Chesterbrook Boulevard, Suite 300, Berwyn, PA 19312. The Corporate Secretary will forward such communications to the relevant group or individual at or prior to the next meeting of the Board. The Board has instructed our Corporate Secretary to review the correspondence prior to forwarding it, and in his discretion, not to forward certain items if he deems them to be of a commercial or frivolous nature or otherwise inappropriate for the Board's consideration. In these cases, he may forward some of the correspondence elsewhere in the Company for review and possible response.

Luxembourg Corporate Governance.    As a Luxembourg company, we are subject to laws that can significantly restrict our Board's ability to grant certain rights to shareholders under our Articles. For example, Luxembourg law:

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Imposes a supermajority requirement in order to amend our Articles, which cannot be amended by the Board or our shareholders;



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Prohibits a plurality carve out from our majority voting requirement in a contested director election; and



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Requires shareholder action by written consent in lieu of a meeting to be unanimous.

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BOARD STRUCTURE AND COMMITTEE COMPOSITION

Board Structure and Committee Composition

We have a standing audit committee, compensation and talent development committee and a nominating and corporate governance committee with the composition and responsibilities described below. Each committee operates under a charter that has been approved by our Board. A copy of each charter can be found by clicking on "Corporate Governance" and then "Committee Composition" in the Investor Relations section of our website, www.investor.trinseo.com. The members of each committee are appointed by the Board and each member serves until his or her successor is elected and qualified, unless he or she is earlier removed or resigns. In addition, from time to time, special committees may be established under the direction of the Board when necessary to address specific issues.

The table below provides information about the membership of our standing audit, compensation and talent development, nominating and corporate governance and our and environmental, health, safety, sustainability and public policy committees during fiscal 2020:

Name		Audit		Compensation and Talent Development		Nominating and Corporate Governance		Environmental, Health, Safety, Sustainability and Public Policy
K'Lynne Johnson †				Chair		X
Joseph Alvarado		X		​		​		X
Frank Bozich								Chair
Jeffrey J. Cote §		X		X		​		​
Pierre-Marie De Leener		X						X
Jeanmarie Desmond §		X		X		​		​
Matthew Farrell §				X		X
Sandra Beach Lin		​		X		X		​
Philip R. Martens				X		Chair*
Donald T. Misheff §		X		​		X		​
Mark Tomkins §		Chair*						X
​	​	​	​	​	​	​	​	​

†

Denotes Board chair.

§

Denotes Audit Committee Financial Expert

*

Since November 2020.

Audit Committee

The purpose of the audit committee is set forth in the audit committee charter. The audit committee's primary duties and responsibilities are to:

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Appoint or replace, compensate and oversee the outside auditors for the purpose of preparing or issuing an audit report or related work or performing other audit, review or attest services for us and will report directly to the audit committee.



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Pre-approve all auditing services and permitted non-audit services (including the fees and terms thereof) to be performed for us by our outside auditors, which are approved by the audit committee prior to the completion of the audit.



•

Review and discuss with management and the outside auditors the annual audited and quarterly unaudited financial statements, our disclosures under "Management's Discussion and Analysis of Financial Condition and Results of Operations", and the selection, application and disclosure of critical accounting policies and practices used in such financial statements.



•

Review and approve all related party transactions as defined under Item 404(a) of Regulation S-K.



•

Discuss with management and the outside auditors significant financial reporting issues and judgments made in connection with the preparation of our financial statements, including any significant changes in our selection or application of accounting principles, any major issues as to the adequacy of our internal controls and any special steps adopted in light of material control deficiencies.

A copy of the charter, which satisfies the applicable standards of the SEC and the NYSE is available on our website. The audit committee currently consists of Joseph Alvarado, Jeffrey J. Cote, Pierre-Marie De Leener, Jeanmarie Desmond, Donald T. Misheff and Mark Tomkins. Our Board has determined that Ms. Desmond and each of Messrs. Alvarado, Cote, De Leener, Farrell, Misheff and Tomkins are independent directors pursuant to Rule 10A-3(b)(1) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and Section 303A.02 of the New York Stock Exchange Listed Company Manual. Ms. Desmond and each of Messrs. Cote, Farrell, Misheff and Tomkins is also an "audit committee financial expert" within the meaning of Item 407(d)(5) of Regulation S-K. Mr. Tomkins also serves as chair of the audit committee.

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Compensation & Talent Development Committee

The purpose of the compensation and talent development committee (the "compensation committee") is to assist the Board in fulfilling its responsibilities relating to oversight of the compensation of our directors, executive officers and other employees and the administration of our benefits and equity-based compensation programs. The compensation committee reviews and recommends to our Board compensation plans, policies and programs and approves specific compensation levels for all executive officers. The compensation committee currently consists of Jeffrey J. Cote, Jeanmarie Desmond, Matthew Farrell, K'Lynne Johnson, Sandra Beach Lin and Philip R. Martens. Ms. Johnson serves as chair of the compensation committee. A copy of its charter, which satisfies the applicable standards of the SEC and the NYSE, is available on our website. Pursuant to its charter, the compensation committee may delegate to subcommittees of the compensation committee any of the responsibilities of the full committee.

Nominating and Corporate Governance Committee

The purpose of the nominating and corporate governance committee is to (i) identify, screen and review individuals qualified to serve as directors (consistent with criteria approved by our Board) and recommend to our Board candidates for nomination for election at the annual meeting of shareholders or to fill Board vacancies or newly created directorships; (ii) develop and recommend to our Board and oversee the implementation of our corporate governance guidelines; (iii) oversee evaluations of our Board and (iv) recommend to our Board candidates for appointment to board committees. The nominating and corporate governance committee currently consists of Matthew Farrell, K'Lynne Johnson, Sandra Beach Lin, Philip R. Martens, Donald T. Misheff and Henri Steinmetz. Mr. Martens serves as chair of the nominating and corporate governance committee. Our Board has adopted a written charter under which the nominating and corporate governance committee operates, which is available on our website.

Environmental, Health, Safety, Sustainability and Public Policy Committee

The Environmental, Health, Safety, Sustainability and Public Policy Committee (the "EHSS&PP Committee") was established in 2014, for the purpose of assisting the Board in fulfilling its oversight responsibilities by assessing the effectiveness of programs and initiatives that support the environment, health and safety, sustainability, corporate social responsibility and climate change ("Sustainability") policies and programs of the Company. Its duties and responsibilities are to:

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Support alignment between the Company and the Board on the Company's Sustainability, social, and public policy goals;



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Guide the Company on its Sustainability programs, policies, partnerships, activities and goals to ensure consistency with and impact upon the Company's business strategy and the creation of stakeholder value and relationships;



•

Review of external public policy/governmental affairs issues and trends in order to more effectively achieve the Company's business goals, and provide recommendations to the Board regarding the Company's response to these issues consistent with applicable legal and regulatory requirements;



•

Review, approve and recommend to the Board for adoption, the Company's annual public Sustainability and Corporate Social Responsibility Report; and



•

Assist the Board in fulfilling its oversight responsibility for the Company's risk management programs by assessing risks that may arise in connection with the Company's Sustainability, programs, partnerships, activities and goals.

The EHSS&PP Committee currently consists of Joseph Alvarado, Frank A. Bozich, Pierre-Marie De Leener, Henri Steinmetz and Mark Tomkins. Mr. Bozich serves as chair of the EHSS&PP Committee. A copy of its charter is available on the Company's website.