RISK FACTORS

An investment in shares of Delaware Common Stock is subject to a number of risks. Prior to making any decision as to whether or not to vote in favor of the Redomicile Resolution, Zymeworks Securityholders should carefully consider risk factors associated with holding shares of Delaware Common Stock, Parent Warrants and/or Parent Incentive Awards, Zymeworks’ business and the industry in which it operates, together with all other information contained in this Proxy Statement/Prospectus, including, in particular the risk factors described below.

You should carefully consider the following factors as well as the other information contained in and incorporated by reference into this Proxy Statement/Prospectus, and specifically, the factors described in the section entitled “Item 1A. Risk Factors” in the Annual Report on Form 10-K of Zymeworks for the year ended December 31, 2021 and the Quarterly Report on Form 10-Q for the quarter ended June 30, 2022. For information about Zymeworks’ filings incorporated by reference in this Proxy Statement/Prospectus, see section titled “Where You Can Find More Information”. The Risk Factors contained or incorporated by reference in this Proxy Statement/Prospectus are not guarantees that no such conditions exist as of the date of this Proxy Statement/Prospectus and should not be interpreted as an affirmative statement that such risks or conditions have not materialized, in whole or in part.

Risks Relating to Zymeworks’ Business

You should read and consider the risk factors specific to Zymeworks’ business that will continue to affect Parent after completion of the Redomicile Transactions. These risks are described in the section entitled “Item 1A. Risk Factors” in the Annual Report on Form 10-K of Zymeworks for the year ended December 31, 2021, and the section entitled “Item 1A. Risk Factors” in the Quarterly report on Form 10-Q of Zymeworks for the quarter ended June 30, 2022, each of which is incorporated by reference into this Proxy Statement/Prospectus, and in other documents that are incorporated by reference into this Proxy Statement/Prospectus.

Risks Relating to Parent

The rights of stockholders under Delaware law may differ from the rights of shareholders under the BCBCA.

If the Redomicile Transactions are completed, Zymeworks Shareholders (other than Dissenting Shareholders (as defined herein) and holders of Exchangeable Shares prior to exchanging them for Delaware Common Stock) will become stockholders of a Delaware corporation. There are differences between the BCBCA and the DGCL. For example, under the BCBCA, many significant corporate actions such as certain amendments to a corporation’s notice of articles and articles or consummating an amalgamation (other than a vertical short form or horizontal short form amalgamation among affiliated entities) require the approval of at least two-thirds of the votes cast by shareholders, whereas under the DGCL, in most cases, such actions require the approval of a majority of the voting power of outstanding stock entitled to vote on the matter. Furthermore, shareholders under the BCBCA are entitled to appraisal rights under a number of extraordinary corporate actions, including an amalgamation with another unrelated corporation, certain amendments to a corporation’s articles of incorporation or the sale of all or substantially all of a corporation’s assets, whereas under the DGCL, stockholders are only entitled to appraisal rights in connection with certain mergers, consolidations and similar transactions. As shown by the examples above, if the Redomicile Transactions are completed, in certain circumstances, holders of shares of Delaware Common Stock will be afforded different protections under the DGCL than Zymeworks Shareholders had under the BCBCA. See section titled “Comparison of Rights of Zymeworks Shareholders, Exchangeable Shareholders and Parent Stockholders” for further details.

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Delaware law and provisions in the Parent Certificate of Incorporation and Parent Bylaws might delay, discourage or prevent a change in control of Parent or changes in its management, thereby depressing the market price of the Delaware Common Stock.

Parent Certificate of Incorporation and Parent Bylaws will contain provisions that may make the acquisition of Parent more difficult or delay or prevent changes in control of its management. Among other things, these provisions will:

In addition, because Parent will be incorporated in Delaware, Parent will be governed by the provisions of Section 203 of the DGCL, which generally prohibits a Delaware corporation from engaging in any of a broad range of business combinations with any “interested stockholder” for a period of three years following the date on which the stockholder became an “interested stockholder” unless certain conditions are met.

These provisions, alone or together, could delay, discourage or prevent a transaction involving a change in control of Parent. These provisions could also discourage proxy contests and make it more difficult for stockholders to elect directors of their choosing and to cause Parent to take other corporate actions they desire, any of which, under certain circumstances, could limit the opportunity for Parent’s stockholders to receive a premium for their shares of Delaware Common Stock, and could also affect the price that some investors are willing to pay for Delaware Common Stock. For more information, see section titled “Description of Parent Capital Stock – Parent Certificate of Incorporation and Parent Bylaws Provisions”.

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The Parent Bylaws will designate a state or federal court located within the State of Delaware as the exclusive forum for substantially all disputes between Parent and its stockholders, and also provide that the federal district courts will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act, each of which could limit Parent’s stockholders’ ability to choose the judicial forum for disputes with Parent or its directors, officers, stockholders or employees.

The Parent Bylaws will provide that, unless Parent consents in writing to the selection of an alternative forum, the sole and exclusive forum for (1) any derivative action or proceeding brought on Parent’s behalf, (2) any action asserting a claim of breach of a fiduciary duty owed by any of Parent’s directors, stockholders, officers or other employees to Parent or its stockholders, (3) any action arising pursuant to any provision of the DGCL, the Parent Certificate of Incorporation or Parent Bylaws or (4) any other action asserting a claim that is governed by the internal affairs doctrine shall be the Court of Chancery of the State of Delaware (or, if the Court of Chancery does not have jurisdiction, another State court in Delaware or the federal district court for the District of Delaware), except for any claim as to which such court determines that there is an indispensable party not subject to the jurisdiction of such court (and the indispensable party does not consent to the personal jurisdiction of such court within ten days following such determination), which is vested in the exclusive jurisdiction of a court or forum other than such court or for which such court does not have subject matter jurisdiction. This provision would not apply to any action brought to enforce a duty or liability created by the U.S. Exchange Act and the rules and regulations thereunder.

Section 22 of the Securities Act establishes concurrent jurisdiction for federal and state courts over Securities Act claims. Accordingly, both state and federal courts have jurisdiction to hear such claims. To prevent having to litigate claims in multiple jurisdictions and the threat of inconsistent or contrary rulings by different courts, among other considerations, the Parent Bylaws will also provide that, unless Parent consents in writing to the selection of an alternative forum, the federal district courts of the United States will be the sole and exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act.

Any person or entity purchasing or otherwise acquiring or holding or owning (or continuing to hold or own) any interest in any of Parent’s securities shall be deemed to have notice of and consented to the foregoing bylaw provisions. Although Parent believes these exclusive forum provisions benefit Parent by providing increased consistency in the application of Delaware law and federal securities laws in the types of lawsuits to which each applies, the exclusive forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum of its choosing for disputes with Parent or its current or former directors, officers, stockholders or other employees, which may discourage such lawsuits against Parent and its current and former directors, officers, stockholders and other employees. Parent’s stockholders will not be deemed to have waived its compliance with the federal securities laws and the rules and regulations thereunder as a result of Parent’s exclusive forum provisions.

The enforceability of similar exclusive forum provisions in other companies’ organizational documents have been challenged in legal proceedings, and, while certain courts have determined these provisions are enforceable, it is possible that a court of law could rule that these types of provisions are inapplicable or unenforceable if they are challenged in a proceeding or otherwise. If a court were to find either exclusive forum provision contained in the Parent Bylaws to be inapplicable or unenforceable in an action, Parent may incur significant additional costs associated with resolving such action in other jurisdictions, all of which could harm its results of operations.

There has been no prior public trading for the shares of Delaware Common Stock on a national securities exchange and the market price of the shares of Delaware Common Stock may be subject to volatility.

Although the Zymeworks Common Shares have historically been listed on the NYSE, there has been no public trading market for the shares of Delaware Common Stock. Following the listing of the shares of Delaware Common Stock on the NYSE, there can be no assurance that the trading market for such shares will continue to be as active or liquid as was the trading market for the Zymeworks Common Shares prior to the Redomicile Transactions or that the trading price of the shares of Delaware Common Stock following the Redomicile Transactions may not be effectively lower than the trading price of the Zymeworks Common Shares.

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As is the case with the Zymeworks Common Shares, the market price of the shares of Delaware Common Stock may be volatile. The value of an investment in the shares of Delaware Common Stock may decrease or increase abruptly, and such volatility may bear little or no relation to Zymeworks’ performance. The price of the shares of Delaware Common Stock may fall in response to market appraisal of Zymeworks’ strategy or if Zymeworks’ results of operations, clinical progress and/or prospects are below the expectations of market analysts or shareholders. In addition, stock markets have, from time to time, experienced significant price and volume fluctuations that have affected the market price of securities, and may, in the future, experience similar fluctuations which may be unrelated to Parent’s operating performance and prospects but nevertheless affect the price of the shares of Delaware Common Stock. This volatility may affect the ability of holders of shares of Delaware Common Stock to sell these at an advantageous price. Broad market fluctuations, as well as economic conditions generally, may adversely affect the market price of the shares of Delaware Common Stock.

Parent may need to enter into certain new arrangements which may not be on terms as favorable as arrangements entered into by Zymeworks.

Concurrently with or immediately following completion of the Redomicile Transactions, Parent may need to enter into new arrangements as the ultimate parent company to Zymeworks and its subsidiaries. While Parent anticipates such terms will be materially consistent with the arrangements currently in place for Zymeworks, there is no assurance that such arrangement will not impose additional operating or financial restrictions on Parent, or that such arrangements will be on commercially reasonable terms or terms that are acceptable to Parent.

Parent’s ability to pay dividends in the future is not guaranteed.

Any future determination to pay dividends will be at the discretion of the Parent board of directors and will depend upon many factors, including Parent’s results of operations, financial position, capital requirements, distributable reserves, credit terms, general economic conditions and other factors as the Parent board of directors may deem relevant from time to time. Consequently, future dividends payable to investors are not guaranteed.

The issuance of additional shares of Delaware Common Stock in connection with future equity financings, acquisitions or growth opportunities, any Parent Incentive Plan or otherwise may dilute all other shareholdings.

Parent may seek to raise financing for acquisitions or to fund future growth opportunities. In certain circumstances, Parent may, for these and other purposes, including pursuant to any Parent Incentive Plan, issue additional equity or convertible equity securities. As a result, existing holders of shares of Delaware Common Stock may suffer dilution in their percentage ownership or the market price of such shares may be adversely affected.

Risks Relating to the Redomicile Transactions

Zymeworks may fail to realize certain benefits of the Redomicile Transactions, including as a result of the shares of Delaware Common Stock not being included in a U.S. stock market index.

Zymeworks has pursued the Redomicile Transactions because it believes that the Redomicile Transactions will enhance shareholder value over the long-term. Zymeworks believes that the Redomicile Transactions will raise the profile and marketability of Zymeworks’ capital stock in the United States through, among other things, the ability to attract deeper and growing pools of passive investment capital in the United States, particularly if shares of Delaware Common Stock are included in certain U.S. stock market indices and other investment vehicles that only include securities of U.S.-incorporated companies. However, following the Redomicile Transactions, if shares of Delaware Common Stock are not included in such U.S. stock market indices, this could result in increased selling pressure and/or decreased demand for Parent’s shares that would increase stock price volatility or cause the market price of the shares of Delaware Common Stock to fall. Initial inclusion and

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continued inclusion in a stock market index or fund is not guaranteed and is subject to numerous factors which can be applied subjectively by the entity managing the index or fund. There are no assurances that Parent will be included in any U.S. stock market indices or funds in a timely manner, or at all. Even if Parent is included in a U.S. stock market index or fund, the entities managing such indices or funds may change their inclusion criteria, resulting in the future exclusion from such index or fund.

The success of the Redomicile Transactions will depend, in part, on the ability of Zymeworks to realize the anticipated benefits associated with the Redomicile Transactions and associated reorganization of Zymeworks’ corporate structure, and Zymeworks may not be able to realize such benefits on a timely basis or at all.

The Redomicile Transactions may result in sales of shares of Delaware Common Stock by certain retail and institutional shareholders or investment funds that are not permitted to hold shares of Delaware Common Stock under their internal guidelines.

The Redomicile Transactions may result in sales of shares of Delaware Common Stock by certain retail and institutional shareholders or investment funds (including Canadian-focused funds) that are not permitted to hold shares of Delaware Common Stock under their internal guidelines, or are limited in the size of any such investments. Such sales could result in increased selling pressure and/or decreased demand for Parent’s shares of Delaware Common Stock, which could increase stock price volatility or cause the market price of the shares of Delaware Common Stock to fall. As a result of the foregoing, certain of these investors may be required under their internal guidelines to sell their shares at times when, or at prices for which, they would otherwise not have sold. If an investor sells its shares at a time when the market price is lower than their cost basis in the shares, the investor will suffer a loss that could be significant to such investor.

The success of the Redomicile Transactions will depend, in part, on the ability of Zymeworks to realize the anticipated benefits associated with the Redomicile Transactions and associated reorganization of Zymeworks’ corporate structure, and Zymeworks may not be able to realize such benefits on a timely basis or at all.

Zymeworks’ business may be impacted by the uncertainty associated with the Redomicile Transactions.

Although Parent expects to maintain Zymeworks’ existing physical operations in Canada and Washington state, the Company’s principal executive offices will be located in Middletown, Delaware, which reflects the ongoing evolution of our workforce toward hybrid and remote, with maintenance of our historical physical operations. As a result of this shift, certain relationships, including with employees, suppliers, contract research organizations, partners, collaborators, governments and other stakeholders, may be subject to disruption due to uncertainty associated with the Redomicile Transactions. Specifically, certain stakeholders may be reluctant to engage in business with Zymeworks prior to, or with Parent following completion of, the Redomicile Transactions, or may impose additional conditions on or apply less favorable terms to transactions involving Zymeworks and/or Parent. This could have an adverse effect on the business and operations of Zymeworks prior to, or Parent following, completion of the Redomicile Transactions.

The Redomicile Transactions are conditional, and the conditions may not be satisfied.

Completion of the Redomicile Transactions is conditional, among other things, upon the receipt of approvals and the satisfaction of other conditions, including (a) the authorization, upon official notice of issuance, of the listing of the shares of Delaware Common Stock on the NYSE, (b) the approval of the Court in respect of the Arrangement, and (c) the receipt of the Required Securityholder Approvals. Although Zymeworks is diligently applying its efforts to take, or cause to be taken, all actions to do, or cause to be done, all things necessary, proper or advisable to obtain the requisite approvals, there can be no assurance that these conditions will be fulfilled or that the Redomicile Transactions will be completed. Further, even if the Required Securityholder Approvals have been obtained, the Zymeworks Board may decide to delay or not proceed with the Redomicile Transactions if it determines that the Redomicile Transactions are no longer advisable.

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Distributions to Non-U.S. holders of Delaware Common Stock may be subject to U.S. withholding

Distributions by Parent on Delaware Common Stock held by Non-U.S. holders (as defined below) (including constructive distributions) may be subject to a U.S. federal withholding tax (generally, at a rate of 30% of the gross amount of the dividend or such lower rate as may be specified by an applicable income tax treaty between the United States and the Non-U.S. holder’s country of residence). For more information, see section titled “Material U.S. Federal Income Tax Considerations – Material U.S. Federal Income Tax Considerations to Non-U.S. Holders of Ownership and Disposition of Delaware Common Stock – Distributions”.

Parent’s effective tax rate may change in the future, including as a result of the Redomicile Transactions.

Following the Redomicile Transactions, Parent will be subject to U.S. federal income taxes on its earnings and the earnings of its non-U.S. subsidiaries in a manner that may adversely impact the company’s effective tax rate. For example, Parent may have to include additional amounts in income as a result of the application of “controlled foreign corporation” rules, including under the so-called “global intangible low-taxed income” regime, or the recently enacted 15% minimum tax on book income and 1% excise tax on stock redemptions. In addition, Parent may have to comply with U.S. withholding tax requirements on U.S. federal distributions paid to non-U.S. holders. Currently, the U.S. federal corporate income tax rate is 21%, and the Canadian corporate income tax rate (federal and provincial) is 27%. In addition, Zymeworks’s tax attributes (including net operating loss and tax credit carryforwards and deductible Scientific Research and Experimental Development Expenditure carryforwards) will generally not be available to offset U.S. income and may be subject to limitation following the Redomicile Transactions.

Further, Parent’s future operations and business structure may result in increased tax burden. For example, changes in Parent’s clinical development plans and business or commercialization strategies may result in an increased effective tax rate. Taxation of international business operations and intercompany transactions, including transactions between Parent and non-U.S. subsidiaries, is complicated. Any changes in the U.S. or non-U.S. taxation of such activities may increase Parent’s worldwide effective tax rate and harm Parent’s business, financial condition, and results of operations.

Zymeworks will allocate time and resources to effecting the Redomicile Transactions and incur non-recurring costs related to the Redomicile Transactions.

Zymeworks and its management have allocated and will continue to be required to allocate time and resources to effecting the completion of the Redomicile Transactions and related and incidental activities. There is a risk that the challenges associated with managing these various initiatives as described in this Proxy Statement/Prospectus may have a business impact and that consequently the underlying businesses will not perform in line with expectations. This could have an adverse effect on the business, financial condition and reputation of Parent.

In addition, Zymeworks expects to incur a number of non-recurring costs associated with the Redomicile Transactions, including legal fees, accountants’ fees, proxy solicitor fees, filing fees, mailing expenses and financial printing expenses. There can be no assurance that the actual costs will not exceed those estimated and the actual completion of the Redomicile Transactions may result in additional and unforeseen expenses. Most of these costs will be payable whether or not the Redomicile Transactions are completed. While it is expected that benefits of the Redomicile Transactions achieved by Parent will offset these transaction costs over time, this net benefit may not be achieved in the short-term or at all, particularly if the Redomicile Transactions are delayed or does not happen at all. These combined factors could adversely affect the business and overall financial condition of Parent.

Zymeworks may choose to defer or abandon the Redomicile Transactions.

Even if the Required Securityholder Approvals have been obtained and other conditions required to complete the Redomicile Transactions have been satisfied, Zymeworks may decide to defer or abandon the Redomicile

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Transactions at any time prior to the Effective Time of the Redomicile Transactions and in such case Zymeworks will have incurred costs and will have directed attention and resources relating to the Redomicile Transactions, but will not realize any of the anticipated benefits of the Redomicile Transactions.

Negative publicity resulting from the Redomicile Transactions could adversely affect Zymeworks’ business and the market price of the Zymeworks Common Shares and the shares of Delaware Common Stock.

Transactions similar to the Redomicile Transactions that have been undertaken by other companies have in some cases generated significant news coverage, some of which has been negative. Negative publicity generated by the Redomicile Transactions could cause certain persons with whom Zymeworks has a business relationship to be more reluctant to do business with Zymeworks prior to the Redomicile Transactions, or Parent following the Redomicile Transactions. In addition, negative publicity could cause certain of Zymeworks’ employees, particularly those in Canada, to perceive uncertainty regarding future opportunities available to them. Either of these events could have a significant adverse impact on Zymeworks’ business. Negative publicity could also cause some Zymeworks Shareholders to sell Zymeworks Common Shares or decrease the demand for new investors to purchase such shares, which could have an adverse impact on the price of the Zymeworks Common Shares and the shares of Delaware Common Stock.

Completion of the Redomicile Transactions may trigger certain provisions in agreements to which Zymeworks is a party.

While the Redomicile Transactions will not result in an effective change of control of Zymeworks, the completion of the Redomicile Transactions may trigger certain technical change in control, right of first offer, notice, consent, assignment or other provisions in agreements to which Zymeworks or its subsidiaries are a party. If Zymeworks and/or Parent are unable to assert that such provisions should not apply, or is unable to comply with or negotiate waivers of those provisions, the counterparties may exercise their rights and remedies under the agreements, including potentially terminating such agreements or seeking monetary damages. Even if Zymeworks is able to negotiate waivers, the counterparties may require a fee for such waivers or seek to renegotiate the agreements on terms less favorable to Parent.

Payments in connection with the exercise of Dissent Rights by Zymeworks Shareholders may impact Parent’s financial resources.

Under the BCBCA, Registered Shareholders who (a) do not vote in favor of the Redomicile Resolution, (b) deliver to Zymeworks a Dissent Notice, (c) continuously hold their Zymeworks Common Shares through the Effective Time, and (d) otherwise comply with the requirements and procedures of Division 2 of Part 8 of the BCBCA (as may be modified by the Interim Order, the Plan of Arrangement, and any further order of the Court), are entitled to receive payment in cash of the “fair value” of their Zymeworks Common Shares. Should a material number of Zymeworks Shareholders exercise Dissent Rights, a substantial cash payment may be required to be made to such Dissenting Shareholders that could have an adverse effect on Parent’s financial condition and cash resources if the Redomicile Transactions are completed. It is a condition precedent to completion of the Redomicile Transactions that the time period for the exercise of any Dissent Rights conferred upon Zymeworks Shareholders in respect of the Redomicile Transactions shall have expired and Zymeworks Shareholders shall not have exercised (or otherwise be deemed to have exercised) Dissent Rights for greater than 10% of the outstanding Zymeworks Common Shares, or such other amount that would make it inadvisable to proceed with the implementation of the Redomicile Transactions, as determined by Zymeworks in its sole discretion.

Enforcement of rights against Parent in Canada may be limited.

Parent’s principal executive offices will be located in Middletown, Delaware and the majority of its directors, officers and experts are likely to reside outside of Canada. Accordingly, it may not be possible for Parent

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stockholders or Exchangeable Shareholders to effect service of process within Canada upon Parent or the majority of its directors, officers or experts, or to enforce judgments obtained in Canadian courts against Parent or the majority of its directors, officers or experts.

Risks Relating to the Exchangeable Shares

The Exchangeable Shares will not be listed on any stock exchange.

The Exchangeable Shares are not expected to be listed on any stock exchange. Although each Exchangeable Share will be exchangeable at the option of the holder for shares of Delaware Common Stock, there is no market through which the Exchangeable Shares may be sold, and holders may not be able to sell their Exchangeable Shares.

Zymeworks Shareholders who elect to receive Exchangeable Shares will experience a delay in receiving Delaware Common Stock from the date they request an exchange, which may affect the value of the shares the holder receives in such exchange.

Zymeworks Shareholders who elect to receive Exchangeable Shares as part of the Consideration with respect to their Zymeworks Common Shares and later request to receive shares of Delaware Common Stock in exchange for their Exchangeable Shares may not receive shares of Delaware Common Stock until a period of time after the applicable request is received. During this period, the market price of the shares of Delaware Common Stock may increase or decrease. Any such increase or decrease would affect the value of the Consideration to be received by such a holder of Exchangeable Shares upon a subsequent sale of shares of Delaware Common Stock received in the exchange.

In addition, pursuant to the terms of the Support Agreement and following completion of the Redomicile Transactions, Parent will file a registration statement or a prospectus supplement to an existing registration statement to register the issuance of Delaware Common Stock issued upon exchange of the Exchangeable Shares. If Parent is delayed in filing such registration statement or prospectus supplement to an existing registration statement, or if the effectiveness of such registration statement or prospectus supplement to an existing registration statement is delayed or suspended, shares of Delaware Common Stock issued upon exchange of the Exchangeable Shares would not be registered, which could impact a holder’s ability to sell such shares in a timely manner.

Exchangeable Shares will not be shares of capital stock of Parent and Exchangeable Shareholders will have limited rights against Parent and its officers and directors.

Zymeworks Shareholders who elect to receive Exchangeable Shares as part of or all of their Consideration should be aware that Exchangeable Shares will not be shares of capital stock of Parent. As a result, Exchangeable Shares will not provide the holders thereof the rights against Parent and its officers and directors that stockholders of Parent have under Delaware law. For example, although officers and directors of Parent owe fiduciary duties to stockholders of Parent, Delaware courts are likely to conclude that such duties are not owed to holders of Exchangeable Shares in such capacity. Prior to the exchange of Exchangeable Shares for shares of Delaware Common Stock, holders of Exchangeable Shares may only rely on contractual rights as beneficiaries under the Trust Agreement and the Support Agreement, such as rights to receive equivalent economic benefits as the holders of Delaware Common Stock and voting rights to be exercised through the share of Special Voting Stock. For additional information about these rights, see “Description of the Exchangeable Shares and Related Agreements” and “Comparison of Rights of Zymeworks Shareholders, Exchangeable Shareholders and Parent Stockholders”.

In addition, holders of Exchangeable Shares may not have standing to bring claims against Parent or its officers and directors, including derivative claims, claims based on a breach of fiduciary duty or other claims seeking to

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enforce the terms of Parent Certificate of Incorporation and Parent Bylaws against the officers and directors of Parent or Parent itself. Moreover, in seeking to enforce rights under the Trust Agreement and Support Agreement, such Exchangeable Shareholders will need to rely on the Share Trustee and may have limited ability to bring direct claims against Parent or its officers or directors. For additional information, see “Comparison of Rights of Zymeworks Shareholders, Exchangeable Shareholders and Parent Stockholders”.

Holders of Exchangeable Shares should also be aware that certain of Parent’s directors and officers, and all or a substantial portion of their assets as well as all or a substantial portion of Parent’s assets are or may be located outside of Canada. As a result, it may be difficult for investors to effect service of process within Canada upon Parent and such directors and officers or to enforce judgments obtained against Parent or such persons, in Canadian courts. Furthermore, as discussed under “The Parent Bylaws will designate a state or federal court located within the State of Delaware as the exclusive forum for substantially all disputes between Parent and its stockholders, and also provide that the federal district courts will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act, each of which could limit Parent’s stockholders’ ability to choose the judicial forum for disputes with Parent or its directors, officers, stockholders or employees”, holders of Exchangeable Shares may be limited in their ability to bring suit against Parent in courts outside of the Court of Chancery of the State of Delaware (or, if the Court of Chancery does not have jurisdiction, another State court in Delaware or the federal district court for the District of Delaware).

Exchangeable Shares will not be entitled to voting rights with respect to ExchangeCo except in limited circumstances.

Except as required by the BCBCA and in respect of any changes to the rights, privileges, restrictions and conditions attached to the Exchangeable Shares, the holders of the Exchangeable Shares will not be entitled as such to receive notice of or to attend any meeting of the shareholders of ExchangeCo or to vote at any such meeting, and the holders of the Exchangeable Shares will not be entitled to class votes except as required by the BCBCA. For additional information, see “Comparison of Rights of Zymeworks Shareholders, Exchangeable Shareholders and Parent Stockholders”.

The CEO and Chair of the Board of Parent is also the sole director of ExchangeCo and Callco and conflicts of interest may arise in the exercise of such roles.

As CEO and Chair of the Board of Parent, Kenneth Galbraith owes fiduciary duties to Parent and its stockholders. As sole director of ExchangeCo, he also owes fiduciary duties to ExchangeCo and a duty of care to the holders of ExchangeCo shares, including the Exchangeable Shareholders. Lastly, as sole director of Callco, he owes fiduciary duties to Callco and a duty of care to shareholders of Callco. Zymeworks Shareholders who elect to receive Exchangeable Shares should be aware that there may be situations in which the interests of Parent stockholders and ExchangeCo shareholders are in conflict. For example, if Parent declares a dividend or distribution to its stockholders, it must provide for a similar economic benefit to the Exchangeable Shareholders, which benefit may be provided through adjustment of the Exchangeable Share Exchange Ratio rather than provision of an in-kind dividend or distribution if the ExchangeCo board determines that ExchangeCo would be liable for any unrecoverable tax in connection with the payment of an equivalent dividend or distribution. If the value ascribed to such dividend or distribution undervalues such dividend or distribution, the Exchangeable Share Exchange Ratio may be inadequately adjusted, resulting in a loss of economic benefit to the Exchangeable Shareholders. Under the Exchangeable Share Provisions, any adjustment to the Exchangeable Share Exchange Ratio will be conclusive and binding. In addition, where the Exchangeable Share Exchange Ratio is adjusted in lieu of an economically equivalent dividend, the Exchangeable Shareholders will be delayed in receiving the benefit of that adjustment until they exchange their Exchangeable Shares for Delaware Common Stock. As an additional example, in the event of a Parent Control Transaction, the board of directors of ExchangeCo may accelerate the Redemption Date if it determines in good faith that it is not practicable to substantially replicate the Exchangeable Shares in such Parent Control Transaction, or that the redemption of all the outstanding Exchangeable Shares (other than Exchangeable Shares held by Parent and its subsidiaries) is necessary to enable the completion of the Parent Control Transaction in accordance with its terms. In such event, Exchangeable

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Shares held by Exchangeable Shareholders would be exchanged for Delaware Common Stock and such Exchangeable Shareholders may recognize Canadian income tax on any capital gain.

Moreover, for the reasons discussed under “Exchangeable Shares will not be shares of capital stock of Parent and Exchangeable Shareholders will have limited rights against Parent and its officers and directors”, Exchangeable Shareholders may be limited in their ability to seek redress against Parent and its directors and officers. Furthermore, ExchangeCo will have limited assets and any successful claim asserted by Exchangeable Shareholders against ExchangeCo may not result in adequate compensation as a result of such limited assets.

Holders of Exchangeable Shares will not be entitled to receive Delaware Rights under the Delaware Rights Agreement unless and until they exchange their Exchangeable Shares for shares of Delaware Common Stock.

Delaware Rights will only be issued in respect of shares of Delaware Common Stock. Accordingly, Zymeworks Shareholders who elect to receive Exchangeable Shares will not be entitled to receive Delaware Rights under the Delaware Rights Agreement unless and until their Exchangeable Shares are exchanged for shares of Delaware Common Stock.

There may be a taxable event for an Eligible Holder as a result of a transaction beyond such Eligible Holder’s control.

An Eligible Holder who (a) disposes of Zymeworks Common Shares pursuant to the Plan of Arrangement and who receives consideration that includes Exchangeable Shares, and (b) validly makes a joint election under subsection 85(1) or subsection 85(2) of the Tax Act (as applicable and as described in the sections titled “Material Canadian Federal Income Tax Considerations — Exchange of Zymeworks Common Shares for Exchangeable Shares — Section 85 Election” and “Material Canadian Federal Income Tax Considerations — Exchange of Zymeworks Common Shares for Exchangeable Shares and Delaware Common Stock — Section 85 Election”) in respect of such shares, may obtain a full or partial tax deferral of any capital gain that may otherwise arise on the exchange of such Zymeworks Common Shares. However, a holder of Exchangeable Shares will be considered to have disposed of Exchangeable Shares (a) on a redemption (including pursuant to a retraction request) of such Exchangeable Shares by ExchangeCo, and (b) on an acquisition of such Exchangeable Shares by Callco or Parent. Although each is a taxable event, the Canadian federal income tax consequences of the disposition will be different depending on whether the event giving rise to the disposition is a redemption or an acquisition. Further, if the Exchangeable Share Cap is reached, then the Exchangeable Shares will be allocated proportionally among the applicable Eligible Holders based on the number of Exchangeable Shares requested and rounded down to the nearest whole share in respect of each Eligible Holder, in which case, the Eligible Holder will also be issued Delaware Common Stock under a Mixed Election.

Prior to the Sunset Date, ExchangeCo may redeem Exchangeable Shares in limited circumstances, and ExchangeCo shall redeem the Exchangeable Shares on the Sunset Date. Accordingly, an Eligible Holder may have a taxable event in a transaction beyond their control. See section titled “Material Canadian Federal Income Tax Considerations” for further information.

Receipt of Delaware Common Stock by Eligible Holders who do not elect to receive Exchangeable Shares with respect to their Zymeworks Common Shares will be a taxable event for Canadian income tax purposes, and could also be taxable to Zymeworks Shareholders who are not U.S. holders (as defined below).

An Eligible Holder who does not elect to receive Exchangeable Shares with respect to their Zymeworks Common Shares and instead disposes of Zymeworks Common Shares for Delaware Common Stock will realize proceeds of disposition equal to the aggregate fair market value, at the time of the disposition, of the Delaware Common Stock acquired on the exchange. Such Eligible Holder will realize a capital gain (or capital loss) equal

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to the amount by which the proceeds of disposition, net of any reasonable costs of disposition, exceed (or are less than) the adjusted cost base to such Eligible Holder of the Zymeworks Common Shares. See section titled “Material Canadian Federal Income Tax Considerations” for further information.

Further, receipt of Delaware Common Stock by Zymeworks Shareholders who are not U.S. holders (as defined below) could be taxable to such Zymeworks Shareholders under the laws of their respective jurisdictions. Such Zymeworks Shareholders should consult with their own tax advisors regarding the tax consequences of the Redomicile Transactions in their particular circumstances.

The tax treatment of Exchangeable Shares for non-Canadian tax purposes is uncertain.

The tax treatment of Exchangeable Shares for non-Canadian tax purposes, including U.S. federal income tax purposes, is uncertain and may differ from the general tax consequences described in section titled “Material Canadian Federal Income Tax Considerations”. Exchangeable Shareholders who are subject to taxation in jurisdictions other than Canada should consult with their tax advisors regarding the tax treatment of Exchangeable Shares under non-Canadian tax laws and regulations.

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VOTING INFORMATION

Voting Shares and Principal Holders

As of the Record Date for the Special Meeting, 61,694,387 Zymeworks Common Shares, 4,794,224 Zymeworks Warrants and 8,131,042 Zymeworks Incentive Awards were outstanding. The Zymeworks Common Shares trade under the stock symbol “ZYME” on the NYSE.

As of the Record Date for the Special Meeting, the directors and executive officers of Zymeworks had the right to vote approximately 34,710 Zymeworks Common Shares, representing approximately 0.06% of the Zymeworks Common Shares then issued and outstanding and entitled to vote at the Special Meeting, no Zymeworks Warrants then issued and outstanding and 2,225,972 Zymeworks Incentive Awards, representing approximately 27.38% of the Zymeworks Incentive Awards then issued and outstanding and entitled to vote at the Special Meeting.

For information regarding each person known by Zymeworks to beneficially own 5% or more of the outstanding Zymeworks Common Shares and information regarding beneficial ownership of Zymeworks Common Shares by directors and executive officers of Zymeworks, see section titled “Share Ownership of Certain Beneficial Owners and Management and Directors of Zymeworks”.

It is expected that each of the directors and executive officers of Zymeworks will vote FOR the Redomicile Resolution.

Record Date and Entitlement to Vote

Each Zymeworks Securityholder of record at the close of business on August 24, 2022, which is the Record Date of the Special Meeting, will be entitled to vote at the Special Meeting the Zymeworks Common Shares, Zymeworks Warrants and Zymeworks Incentive Awards registered in his, her or its name on that date. Each Zymeworks Common Share, Zymeworks Warrant and Zymeworks Incentive Award carries the right to one vote for the Redomicile Resolution.

Quorum

In order for business to be conducted at the Special Meeting, a quorum must be present. A quorum for the Special Meeting requires at least 30% of the Zymeworks Common Shares entitled to vote be present or represented by proxy and at least two persons entitled to vote at the Special Meeting be present or represented by proxy. While Zymeworks Warrantholders and Zymeworks Incentive Awardholders will be entitled to vote at the Special Meeting as described elsewhere in this Proxy Statement/Prospectus, there is no separate quorum requirement under the BCBCA.

Proxy Voting

The persons named in the form of proxy must vote your Zymeworks Common Shares, Zymeworks Warrant or Zymeworks Incentive Awards in accordance with your instructions on the form of proxy. Signing the form of proxy gives authority to the persons named therein, each of whom is either a director or officer of Zymeworks, to vote your Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards at the Special Meeting in accordance with your voting instructions.

In the absence of such instructions, however, your Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards will be voted FOR the Redomicile Resolution.

If you are a registered Zymeworks Shareholder, Zymeworks Warrantholder or Zymeworks Incentive Awardholder, you may vote by completing and returning a proxy according to the instructions below, or by attending the Special Meeting in person.

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A proxy must be in writing and must be executed by you or by an attorney duly authorized in writing or, if the shareholder is a corporation or other legal entity, by a duly authorized officer or attorney.

The persons named in the form of proxy will have discretionary authority with respect to amendments or variations to matters identified in the Notice of Special Meeting and with respect to other matters that properly come before the Special Meeting. As of the date of this Proxy Statement/Prospectus, Zymeworks’ management knows of no such amendment, variation or other matter expected to come before the Special Meeting. If any other matters properly come before the Special Meeting, the persons named in the form of proxy will vote on them in accordance with their best judgment.

If you are a beneficial Zymeworks Shareholder, the Intermediary (usually a bank, trust company, broker, securities dealer or other financial institution) through which you hold your Zymeworks Common Shares will send you instructions on how to vote your Zymeworks Common Shares. Please follow the instructions on your voting instruction form.

Computershare Investor Services Inc.

Proxy Department

100 University Avenue, 8th Floor

Toronto, Ontario

M5J 2Y1

In addition, Zymeworks or its strategic shareholder advisor, proxy solicitation agent and information agent, Kingsdale Advisors, may utilize the Broadridge QuickVote^™ service to assist non-registered Zymeworks Shareholders with voting their Common Shares over the telephone.

The persons named in the enclosed form of proxy are either directors or officers of Zymeworks. Please see section titled “Voting Information — Proxy Voting” above. You have the right to appoint some other person of your choice, who need not be a Zymeworks Shareholder, director or officer, to attend and act on your behalf at the Special Meeting. If you wish to do so, please write the name of this person or entity, who need not be a shareholder, in the blank space provided in the form of proxy. If you decide to vote by telephone, you cannot appoint a person to vote your Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards other than Zymeworks’ directors or officers whose printed names appear on the form of proxy. It is important to ensure that any other person you appoint as proxy is attending the Special Meeting and is aware that his or her appointment has been made to vote your Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards.

Voting in Person

If you wish to vote in person, you do not need to complete or return your form of proxy. On the day of Special Meeting you will have to present yourself to a representative of Computershare at the registration table. Your vote will be taken and counted at the Special Meeting.

Any COVID protocols mandated by applicable local authorities that are in effect on the date of the Special Meeting will apply, to the extent applicable to the Special Meeting. All attendees will be asked to present a valid government-issued photo identification, such as a driver’s license or passport. The name on your photo identification will be verified against the list of Zymeworks Securityholders of record as of the Record Date prior to your being admitted to the Special Meeting. If you do not have valid photo identification and we are unable to verify your ownership of Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards as of the Record Date, you will not be admitted into the Special Meeting.

Deadline for Voting

Your duly completed form of proxy must be deposited with Computershare Investor Services Inc., Proxy Department, 100 University Avenue, 8th Floor, Toronto, Ontario, M5J 2Y1, before 9 a.m. (Pacific time) on October 5, 2022, or if the Special Meeting is adjourned or postponed, no later than 9 a.m. (Pacific time) on the second business day preceding the day to which the Special Meeting is adjourned or postponed. Notwithstanding the foregoing, the Chair of the Special Meeting has the discretion to accept proxies received after such deadline and the time limit for deposit of proxies may be waived or extended by the Chair of the Special Meeting at his or her discretion, without notice.

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Revoking your Proxy

As a Registered Shareholder, Zymeworks Warrantholder or Zymeworks Incentive Awardholder, you can change or revoke a previously delivered proxy in the following ways:

Any revocation of a proxy must be delivered either to the registered office of Zymeworks at any time up to and including the last business day preceding the day of the Special Meeting or any adjournment or postponement of the Special Meeting, or to the Chair of the Zymeworks Board on the day of the Special Meeting, October 7, 2022, or any adjournment or postponement of the Special Meeting, prior to the time of the Special Meeting.

Beneficial Shareholder Voting

You are a beneficial Zymeworks Shareholder if your Zymeworks Common Shares are held in a nominee’s name such as a bank, trust company, securities broker or other nominee. Typically, the form of proxy or voting instruction form sent or to be sent by your nominee indicates whether you are a beneficial Zymeworks Shareholder. Generally, without specific instructions, brokers and their agents or nominees are prohibited from voting shares for their client.

How to Vote

If you are eligible to vote and you are a beneficial Zymeworks Shareholder or a Zymeworks Warrantholder or a Zymeworks Incentive Awardholder, you can vote your Zymeworks Common Shares, Zymeworks Warrants or Zymeworks Incentive Awards in person at the Special Meeting or by voting instructions, as explained below. Voting by providing voting instructions is the easiest way to vote your Zymeworks Common Shares.

Voting Instructions

You will have received this Proxy Statement/Prospectus from your nominee, together with a request for voting instructions for the number of Zymeworks Common Shares you hold. If you do not plan on attending the Special Meeting, or do not otherwise wish to vote in person at the Special Meeting, please follow the voting instructions provided by your nominee.

Each nominee has its own procedures, which you should carefully follow to ensure that your Zymeworks Common Shares are voted at the Special Meeting. These procedures generally allow voting in person or by proxy (telephone, fax, mail or Internet). Beneficial Shareholders should contact their nominee for instructions in this regard.

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Whether or not you attend the Special Meeting, you can appoint someone else to attend and vote as your proxyholder. To do this, please follow the procedures of your nominee carefully. The persons already named in the form of proxy are either directors or officers of Zymeworks. Please see section titled “Voting Information — Proxy Voting” above. It is important to ensure that any other person you appoint as proxy is either attending the Special Meeting in person or returning a proxy reflecting your instructions and is aware that his or her appointment has been made to vote your Zymeworks Common Shares.

Voting in Person

If you wish to vote in person at the Special Meeting, insert your own name in the space provided on the request for voting instructions or form of proxy to appoint yourself as proxyholder and follow the instructions of your nominee.

If you wish to attend and vote your Zymeworks Common Shares at the Special Meeting, Zymeworks will have no record of your shareholdings or of your entitlement to vote unless your nominee has appointed you as proxyholder. Therefore, if you wish to vote in person at the Special Meeting, insert your own name in the space provided on the voting instruction form sent to you by your nominee. Then sign and return the voting instruction form by following the signing and returning instructions provided by your nominee. By doing so, you are instructing your nominee to appoint you as proxyholder. Do not otherwise complete the voting instruction form as your vote will be taken at the Special Meeting. Please register with the transfer agent, Computershare, upon arrival at the Special Meeting.

Deadline for Voting

If voting by voting instructions, your nominee must receive your voting instructions in sufficient time for your nominee to act on them. Every nominee has its own procedures which you should carefully follow to ensure that your Zymeworks Common Shares are voted at the Special Meeting. For your vote to count it must be deposited with our Transfer Agent before 9 a.m. (Pacific time) on October 5, 2022, or if the Special Meeting is adjourned or postponed, no later than 9 a.m. (Pacific time) on the second business day preceding the day to which the Special Meeting is adjourned or postponed.

Revoking Voting Instructions

To revoke your voting instructions, follow the procedures provided by your nominee.

If you have any questions or require assistance with voting, please contact Zymeworks’ strategic shareholder advisor, proxy solicitation agent, and information agent, Kingsdale Advisors, at 1-855-476-7981 (toll-free) or via email at contactus@kingsdaleadvisors.com.

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THE REDOMICILE TRANSACTIONS AND THE PLAN OF ARRANGEMENT

Background to the Redomicile Transactions

As part of our continuous evaluation of our business, the Zymeworks Board, along with management, monitors investor sentiment and capital market trends for opportunities to enhance shareholder value. From time to time, over the past several years, we have analyzed a potential redomiciling of our business to the state of Delaware as a way to help build shareholder value.

In connection with executive management and other organizational changes in January 2022, management began revisiting the potential of redomiciling to the state of Delaware, and in February 2022 management commenced a detailed review of the proposed Redomicile Transactions, with the assistance of financial, legal, accounting and tax advisors.

On March 8, 2022, management presented to the Zymeworks Board its initial analysis regarding a potential redomiciling transaction, including available transaction structures, tax implications, anticipated benefits and potential risks. As part of its review, the Zymeworks Board discussed with management and its advisors the potential Redomicile Transactions and how the proposed transaction could enhance shareholder value. Among other reasons, management discussed with the Zymeworks Board that the Redomicile Transactions (a) would eliminate restrictions on investments imposed on certain U.S. institutional shareholders by virtue of Zymeworks being incorporated outside of the United States, (b) may make Zymeworks eligible for inclusion in certain leading stock indices, such as the Russell and S&P indices, which are not available to foreign corporations and which, if included in such indices, could potentially increase passive investment interest and provide opportunities for increased value for our shareholders, (c) could provide enhanced flexibility for the monetization of non-core assets, (d) could simplify future transactions with potential U.S. counterparties by eliminating or reducing the complexities inherent in cross-border transactions, and (e) would provide Zymeworks with the benefits of Delaware corporate law, which is widely recognized as the preeminent jurisdiction for incorporation in the United States and is better understood by U.S. investors due to the significant number of U.S.-listed companies that are incorporated by Delaware, including the vast majority of Zymeworks’ peer companies. As part of the presentation, management also discussed with the Zymeworks Board other opportunities that could benefit shareholders if Zymeworks were to have a Delaware-incorporated company as the public company. Among other reasons, the Redomicile Transactions could help streamline U.S. commercialization of our lead product candidate, zanidatamab, by reducing or eliminating cross-border legal, regulatory and tax complexities.

In addition to the potential benefits of the Redomicile Transactions, management discussed with the Zymeworks Board potential risks associated with the Redomicile Transactions, including tax considerations and complexities related to available transaction structures. In light of the potential benefits and with due consideration given to the potential risks, the Zymeworks Board directed management to review the costs of the potential Redomicile Transactions and to continue additional work to analyze the merits and risks of having a Delaware incorporated company as the public company, as well as associated corporate governance and capital structure changes.

On May 23, 2022, management presented to the Zymeworks Board an updated analysis regarding the potential Redomicile Transactions, including key transaction steps, estimated timeline to complete the Redomicile Transactions, and factors that could impact that timeline.

On July 14, 2022, management and management’s advisors presented to the Zymeworks Board their final analysis and recommendations regarding the potential reincorporation, including updated key transaction steps, estimated timelines to complete the potential reincorporation and related considerations.

In addition to a review of management’s recommendations, the Zymeworks Board discussed with management and management’s advisors the potential benefits and risks of the redomicile to Delaware, including those set forth in the section of this proxy statement/prospectus titled “Risk Factors — Risks Relating to the Redomicile

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Transactions”. The Zymeworks Board also received advice regarding the anticipated tax treatment applicable to Canadian and U.S. shareholders, as discussed in the section of this proxy statement/prospectus titled “Risk Factors — Risks Relating to the Exchangeable Shares”.

The Zymeworks Board reviewed the plan for the Redomicile Transactions and the Transaction Agreement and associated Plan of Arrangement. Following extensive discussion of the key considerations of the Redomicile Transactions, including those noted under “The Redomicile Transactions and the Plan of Arrangement — Reasons for the Redomicile Transactions”, and after consulting with management and receiving information provided to management by its advisors, the Zymeworks Board determined that the Redomicile Transactions are in the best interests of Zymeworks. Then, the Zymeworks Board approved proceeding with the Redomicile Transactions and recommended that Zymeworks Securityholders vote in favor of the Redomicile Resolution.

On July 15, 2022, prior to the opening of trading on the NYSE, Zymeworks issued a news release announcing the Redomicile Transactions.

On August 18, 2022, Zymeworks, Parent, ExchangeCo and Callco entered into a Restated and Amended Transaction Agreement to make certain amendments to clarify in the Transaction Agreement, the Plan of Arrangement and the Voting Trust (as applicable) (i) the Consideration under the Plan of Arrangement where a Mixed Election is selected, (ii) the application of the Exchangeable Share Cap, (iii) certain Post-Arrangement Transactions, and (iv) the establishment of the trust under the Voting Trust.

Recommendation of the Zymeworks Board

At its meeting held on July 14, 2022, after careful consideration of, among other things, the advice of management and after considering information provided to management by Zymeworks’ tax, accounting and legal advisors and such other matters considered relevant, the Zymeworks Board determined that the Redomicile Transactions (including the Plan of Arrangement and the transactions to be completed as soon as practicable following the Arrangement as set forth in the Transaction Agreement) are in the best interests of Zymeworks. Accordingly, the Zymeworks Board recommends that Zymeworks Securityholders vote FOR the Redomicile Resolution.

Reasons for the Redomicile Transactions

The Zymeworks Board determined that the Redomicile Transactions (including the Plan of Arrangement and the transactions to be completed as soon as practicable following the Arrangement as set forth in the Transaction Agreement) are in the best interests of Zymeworks and believes that the opportunity to enhance long-term value for shareholders will be greater as a Delaware corporation than as a British Columbia corporation. In recommending that Zymeworks Securityholders vote in favor of the Redomicile Resolution, the Zymeworks Board considered and relied upon a number of factors, including, among other things, the following:

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The Zymeworks Board considered a number of other factors pertaining to the Redomicile Transactions as generally supporting its decision to recommend the Redomicile Transactions, including, but not limited to, the following material factors:

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In the course of their deliberations, the Zymeworks Board, in consultation with management and after considering information provided to management by Zymeworks’ legal, accounting and tax advisors, also considered a variety of risks (as described in greater detail under the heading “Risk Factors”) and other potentially negative factors relating to the Redomicile Transactions, including the following:

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The foregoing description of the information and factors considered by the Zymeworks Board includes the principal positive and negative factors considered by them, but is not intended to be exhaustive and may not include all of the factors considered, and, in view of the number and complexity of factors considered by the Zymeworks Board, the Zymeworks Board did not find it practicable to, nor did it attempt to, quantify, rank or otherwise assign relative weights to the specific factors considered by them in making their recommendations (and individual members of the Zymeworks Board may have given different weights to different factors). The Zymeworks Board reached their recommendation based on the totality of the information presented to, and considered by, them through their deliberations.

The foregoing discussion of the information and factors considered by the Zymeworks Board is forward-looking in nature. This information should be read in light of the factors set forth in the sections entitled “Information Contained in Proxy Statement/Prospectus”, “Cautionary Statement Regarding Forward-Looking Statements”, “The Redomicile Transactions and the Plan of Arrangement — Background to the Redomicile Transactions” and “Risk Factors”.

Particulars of the Redomicile Transactions

The following summary of certain transaction steps of the Redomicile Transactions is qualified in its entirety by reference to the full text of Transaction Agreement, which is set forth in Appendix B to this Proxy Statement/Prospectus, and the Plan of Arrangement, a copy of which is attached as Exhibit A to the Transaction Agreement.

The Redomicile Transactions are being implemented in accordance with the terms of and subject to the conditions contained in the Transaction Agreement (including, with respect to the Arrangement and the Plan of Arrangement). Pursuant to the terms of the Plan of Arrangement, the Arrangement will be completed at the Effective Time. The Redomicile Transactions are subject to the satisfaction or waiver of the conditions thereto as set out in the Transaction Agreement. See section titled “Summary of the Transaction Agreement”.

The purpose of the Redomicile Transactions is to facilitate a series of transactions which will occur in a specific sequence and as a consequence of which, among other things: (a) Zymeworks Shareholders will receive, at their election and subject to applicable eligibility criteria, for their Zymeworks Common Shares, either (i) shares of Delaware Common Stock on a one-for-one basis, or (ii) Exchangeable Shares on a one-for-one basis, or a mix of Exchangeable Shares and Delaware Common Stock (in such aggregate number that is equal to the number of Zymeworks Common Shares exchanged for them), subject to the Exchangeable Share Cap; (b) Parent, Callco and ExchangeCo will enter into the Support Agreement; and (c) Parent, ExchangeCo, Callco and Share Trustee will enter into the Trust Agreement for the benefit of the Exchangeable Shareholders. If the Exchangeable Share Cap is reached, then the Exchangeable Shares shall be allocated proportionally among the applicable Eligible Holders based on the number of Exchangeable Shares requested and rounded down to the nearest whole share in respect of each Eligible Holder, in which case, the Eligible Holder will also be issued Delaware Common Stock under a Mixed Election.

Shares of Delaware Common Stock will be listed on the NYSE under the symbol “ZYME”. See section titled “The Redomicile Transactions and the Plan of Arrangement — Certain Legal and Regulatory Matters — Stock Exchange Listings”.

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Plan of Arrangement Steps

Pursuant to the Plan of Arrangement, commencing at the time determined by Zymeworks on the Effective Date (expected to be prior to open of trading on the NYSE), each of the following events or transactions shall occur and be deemed to occur in the following sequence and five minutes following the event(s) in the immediately preceding section, without any further act or formality, unless specifically noted:

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Zymeworks and Parent may amend, modify and/or supplement the Plan of Arrangement at any time and from time to time prior to the Effective Date, provided that any such amendment, modification or supplement must be contained in a written document which is: (a) filed with the Court and, if made following the Special Meeting and adversely affecting the economic interest of any Zymeworks Securityholder, approved by the Court; and (b) if required by the Court, communicated to the Zymeworks Securityholders in the manner required by the Court.

Post-Arrangement Transactions

After the Effective Time and Zymeworks’ election to be treated as a private corporation for Canadian tax purposes, and as part of the Redomicile Transactions, the following additional steps will take place:

Effect of the Redomicile Transactions on the Original Rights

On June 9, 2022, the Zymeworks Board authorized and declared a dividend distribution of one Original Right for each outstanding Zymeworks Common Share to Zymeworks Shareholders of record as of the close of business on June 21, 2022. Each Original Right entitles the registered holder to purchase from Zymeworks one one-thousandth of a Series A Preferred Share of Zymeworks at an exercise price of $74.00, subject to adjustment. The complete terms of the Original Rights are set forth in the Zymeworks Rights Agreement, dated as of June 9, 2022, between the Company and Computershare Trust Company, N.A., as rights agent.

The Zymeworks Board adopted the Zymeworks Rights Agreement to protect Zymeworks Shareholders from coercive or otherwise unfair takeover tactics. In general terms, the Zymeworks Rights Agreement imposes a significant penalty on any person or group that acquires 10% or more (or 20% or more in the case of certain institutional investors who report their holdings on Schedule 13G) of the Zymeworks Common Shares without the approval of the Zymeworks Board. The overall effect of the Zymeworks Rights Agreement and the issuance of the Original Rights may be to render more difficult or discourage a merger, amalgamation, arrangement, take-over bid, tender or exchange offer or other business combination involving Zymeworks that is not approved by the Zymeworks Board. However, neither the Zymeworks Rights Agreement nor the Original Rights should interfere with any merger, amalgamation, arrangement, take-over bid, tender or exchange offer or other business combination approved by the Zymeworks Board.

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In connection with the Redomicile Transactions, the Zymeworks Rights Agreement with respect to the Original Rights will be terminated and Parent will adopt the Delaware Rights Agreement with respect to the Delaware Common Stock, which will be substantively similar in all material respects to the Zymeworks Rights Agreement. Under the Delaware Rights Agreement, in connection with the consummation of the Redomicile Transactions, the Parent board of directors will authorize and declare a dividend distribution of one Delaware Right for each outstanding share of Delaware Common Stock that is issued in connection with the Redomicile Transactions. Each Delaware Right will entitle the registered holder to purchase from Parent one one-thousandth of a share of Series B Participating Preferred Stock of Parent at an exercise price of $74.00, subject to adjustment.

For more information with respect to the Zymeworks Rights Agreement, including a summary of its terms, please refer to Zymeworks’ Current Report on Form 8- K filed with the SEC on June 10, 2022. The Zymeworks Rights Agreement is also incorporated as an exhibit to the registration statement of which this Proxy Statement/Prospectus forms a part. For more information on the Delaware Rights Agreement, please see a substantially final form thereof attached as an exhibit to the registration statement of which this Proxy Statement/Prospectus forms a part.

Effect of the Redomicile Transactions on the Zymeworks Incentive Awards

In connection with the Redomicile Transactions, Parent will assume the Zymeworks Incentive Plans, which will become Parent Incentive Plans, and each outstanding Zymeworks Incentive Award will be assumed and be deemed to be exchanged for a Parent Incentive Award. The assumed and exchanged Zymeworks Incentive Awards will remain subject to the terms and conditions of the Zymeworks Incentive Plans, except that the security issuable upon exercise or settlement of the Zymeworks Incentive Award, as applicable, will be shares of Delaware Common Stock rather than Zymeworks Common Shares.

Effect of the Redomicile Transactions on the Zymeworks Warrants

Parent will assume the Zymeworks Warrants in accordance with their terms, except that the security issuable upon exercise will be shares of Delaware Common Stock rather than Zymeworks Common Shares.

Tax Effect of the Redomicile Transactions on Parent

Canadian Federal Income Tax Considerations

For Canadian federal income tax purposes, Zymeworks does not expect the Redomicile Transactions to give rise to corporate-level Canadian federal income tax for Zymeworks or Parent.

U.S. Federal Income Tax Considerations

For U.S. federal income tax purposes, Zymeworks does not expect the Redomicile Transactions to give rise to corporate-level U.S. federal income tax for Zymeworks or Parent.

Directors and Officers of Parent following the Redomicile Transactions

The same persons currently serving as directors and officers of Zymeworks will serve as directors and officers of Parent following the Redomicile Transactions. See section titled “Information Concerning Parent, ExchangeCo and Callco – Directors and Officers of Parent”.

Letter of Transmittal and Election Form

A Letter of Transmittal and Election Form will be mailed to each person who was a registered holder of Zymeworks Common Shares on the Record Date. Each Registered Shareholder must forward a duly completed and executed Letter of Transmittal and Election Form, with accompanying Zymeworks Common Share certificate(s) and/or such other documents and instruments as the Depositary may reasonably require, in order to receive the shares of Delaware Common Stock or Exchangeable Shares, as applicable, to which such Zymeworks Shareholder is entitled under the Redomicile Transactions. It is recommended that Zymeworks Shareholders complete, sign and return the Letter of

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Transmittal and Election Form and accompanying documents to the Depositary as soon as possible. All deposits of Zymeworks Common Shares made under a Letter of Transmittal and Election Form are irrevocable.

Each Registered Shareholder who is an Eligible Holder will have the right to elect to receive Exchangeable Shares or a mix of Exchangeable Shares and Delaware Common Stock (subject to the Exchangeable Share Cap), by delivering a duly completed Letter of Transmittal and Election Form to the Depositary prior to the Election Deadline, being 5:00 p.m. (Vancouver time) on the date before the Special Meeting. Eligible Holders who do not make an election before the Election Deadline, or for whom their election is not properly made with respect to their Zymeworks Common Shares, will receive Delaware Common Stock.

Beneficial Shareholders whose Zymeworks Common Shares are registered in the name of an Intermediary should contact that Intermediary for instructions on making an election with respect to the Consideration that they wish to receive. See “—Procedure for the Exchange of Shares”.

Zymeworks Shareholders who are not Eligible Holders will not have the right to make an election and will receive Delaware Common Stock.

The Letter of Transmittal and Election Form is available as an exhibit to the registration statement of which this Proxy Statement/Prospectus forms a part, and on Zymeworks’ website at www.zymeworks.com, on SEDAR at www.sedar.com and on the SEC’s website at www.sec.gov.

Any use of the mail to transmit a certificate for Zymeworks Common Shares or surrender book-entry Zymeworks Common Shares and a related Letter of Transmittal and Election Form is at the risk of the Zymeworks Shareholder and delivery will be deemed to be effective only when such documents are actually received by the Depositary. If these documents are mailed, it is recommended that registered mail, properly insured, be used.

Whether or not Zymeworks Shareholders forward the certificate(s) representing their Zymeworks Common Shares or surrender their book-entry Zymeworks Common Shares, from and after completion of the Redomicile Transactions, and at the times contemplated in the Plan of Arrangement and the Transaction Agreement, each certificate, agreement, note, document, electronic record, book entry or other instrument (as applicable) that immediately prior to the completion of the Redomicile Transactions represented Zymeworks Securities shall be deemed to represent only the right to receive the consideration in respect of such Zymeworks Securities required under the Plan of Arrangement and the Transaction Agreement, as applicable, less any withholding amounts pursuant to the Plan of Arrangement.

The instructions for exchanging certificates representing Zymeworks Common Shares and depositing such share certificates with the Depositary and surrendering book-entry Zymeworks Common Shares are set out in the Letter of Transmittal and Election Form. The Letter of Transmittal and Election Form provides instructions with regard to lost certificates.

IF YOU ARE A REGISTERED ZYMEWORKS SHAREHOLDER, YOU MUST SURRENDER YOUR ZYMEWORKS COMMON SHARES THROUGH A LETTER OF TRANSMITTAL AND ELECTION FORM BY THE DAY THAT IS THREE YEARS LESS ONE DAY FROM THE EFFECTIVE DATE IN ORDER TO RECEIVE THE SHARES OF DELAWARE COMMON STOCK OR EXCHANGEABLE SHARES TO WHICH YOU ARE ENTITLED UNDER THE PLAN OF ARRANGEMENT. ON SUCH DATE, ANY AND ALL CONSIDERATION TO WHICH SUCH FORMER HOLDER WAS ENTITLED WILL BE DEEMED TO HAVE BEEN CANCELLED AND NONE OF ZYMEWORKS, PARENT, EXCHANGECO OR ANY OTHER PERSON WILL HAVE ANY OBLIGATION TO ISSUE SUCH SHARES OF DELAWARE COMMON STOCK OR EXCHANGEABLE SHARES.

Procedure for the Exchange of Shares

In connection with the Redomicile Transactions, such number of shares of Delaware Common Stock and Exchangeable Shares as is required pursuant to the Redomicile Transactions will be deposited with the Depositary for the benefit of the Zymeworks Shareholders.

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Upon surrender to the Depositary for cancellation of a certificate which immediately prior to the Effective Time represented outstanding Zymeworks Common Shares or book-entry Zymeworks Common Shares that were exchanged and transferred pursuant to the Plan of Arrangement and otherwise affected after giving effect to the Redomicile Transactions, together with the duly completed and executed Letter of Transmittal and Election Form and such additional documents and instruments as the Depositary may reasonably require, the Zymeworks Shareholder surrendering such certificate or book-entry Zymeworks Common Shares will be entitled to receive in exchange therefor, and the Depositary will deliver to such Zymeworks Shareholder, the consideration which such Zymeworks Shareholder has the right to receive under the Redomicile Transactions for such Zymeworks Common Shares (including certificates representing the number of shares of Delaware Common Stock or Exchangeable Shares issued to such holder in accordance with the Redomicile Transactions), less any amounts withheld pursuant to the Plan of Arrangement, and any Zymeworks Common Share certificate or book-entry Zymeworks Common Shares so surrendered will forthwith be cancelled.

Any exchange or transfer of Zymeworks Common Shares pursuant to the Redomicile Transactions will be free and clear of any Liens.

Return of Zymeworks Common Shares

If the Redomicile Transactions are not completed, any deposited Zymeworks Common Shares will be returned to the depositing Zymeworks Shareholder at Zymeworks’ expense upon written notice to the Depositary from Zymeworks, by returning the deposited Zymeworks Common Shares (and any other relevant documents) by first class insured mail in the name of and to the address specified by the Zymeworks Shareholder in the Letter of Transmittal and Election Form or, if such name and address is not so specified, in such name and to such address as shown on the register maintained by Zymeworks’ transfer agent.

Lost Certificates

If a registered Zymeworks Shareholder holds Zymeworks Common Shares in certificated form, the Letter of Transmittal and Election Form submitted by such registered Zymeworks Shareholder to the Depositary must be accompanied by the original certificate(s) evidencing their Zymeworks Common Shares and any required accompanying evidences of authority. If a registered Zymeworks Shareholder’s certificate(s) representing Zymeworks Common Shares have been lost, stolen or destroyed, the registered Zymeworks Shareholder should contact the Depositary at (800) 564-6253 or by calling (514) 982-7555 between the hours of 8:30 a.m. and 8:00 p.m. Eastern Time prior to submitting the Letter of Transmittal and Election Form to make arrangements concerning such certificate(s) (which may include the posting of a bond or other satisfactory indemnification and an affidavit of loss). A registered Zymeworks Shareholder that holds Zymeworks Common Shares in electronic book-entry form does not need to include any share certificates when submitting their Letter of Transmittal and Election Form.

Cancellation of Rights

Until surrendered, each certificate that immediately prior to the Effective Time represented Zymeworks Common Shares or book-entry Zymeworks Common Shares will be deemed after the Effective Time to represent only the right to receive upon such surrender the consideration to which the holder is entitled to receive. Any such certificate, agreement, note, document, electronic record, book entry or other instrument (as applicable) formerly representing Zymeworks Common Shares not duly surrendered on or before the day that is three years less one day from the Effective Date will cease to represent a claim by or interest of any kind or nature against Zymeworks, ExchangeCo or Parent, including without limitation shares of Delaware Common Stock or Exchangeable Shares. On such date, any and all consideration to which such former holder was entitled will be deemed to have been cancelled and none of Zymeworks, Parent, ExchangeCo or any other Person will have any obligation to issue such shares of Delaware Common Stock or Exchangeable Shares.

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Withholding Rights

Zymeworks, Parent, Callco, ExchangeCo and the Depositary shall be entitled to deduct and withhold from any consideration payable to any Zymeworks Securityholder under the Redomicile Transactions, such amounts as Zymeworks, Parent, Callco, ExchangeCo or the Depositary determines, acting reasonably, are required or reasonably believed to be required to be deducted and withheld from such consideration under any provision of any Laws in respect of taxes. Any such amounts shall be treated for all purposes as having been paid to the Person in respect of which such deduction and withholding was made and such deducted and withheld amounts shall be remitted to the appropriate Governmental Entity.

Zymeworks does not expect any withholding to be required for Canadian federal income tax purposes or U.S. federal income tax purposes as a result of the Redomicile Transactions. Refer to “Material Canadian Federal Income Tax Considerations” and “Material U.S. Federal Income Tax Considerations”.

Fractional Shares

No certificates representing fractional Zymeworks Common Shares, shares of Delaware Common Stock or Exchangeable Shares shall be issued.

Depositary

Zymeworks has retained the services of the Depositary for the receipt of the Letter of Transmittal and Election Form and the certificates representing Zymeworks Common Shares, the surrender of book-entry Zymeworks Common Shares and for the delivery of the shares of Delaware Common Stock and Exchangeable Shares in exchange for the Zymeworks Common Shares under the Redomicile Transactions. The Depositary will receive reasonable and customary compensation for its services in connection with the Redomicile Transactions, will be reimbursed for certain reasonable out-of-pocket expenses and will be indemnified against certain liabilities, including liabilities under securities laws and expenses in connection therewith.

Expenses of the Redomicile Transactions

Zymeworks estimates that expenses in the aggregate amount of approximately $4.1 million will be incurred by Zymeworks in connection with the Redomicile Transactions, including legal, tax and accounting advisors, Depositary, transfer agents, proxy solicitor, filing and printing costs and the cost of preparing and mailing this Proxy Statement/Prospectus.

Required Securityholder Approvals

To be effective, the Redomicile Resolution must be approved, with or without variation, by the affirmative vote of at least two-thirds of the votes cast on the Redomicile Resolution, in person or by proxy, by both (a) Zymeworks Shareholders, Zymeworks Warrantholders and Zymeworks Incentive Awardholders, voting together as a single class, and (b) Zymeworks Shareholders, voting separately.

The Zymeworks Board recommends that Zymeworks Securityholders vote FOR the Redomicile Resolution.

Certain Legal and Regulatory Matters

Court Approval

An Arrangement under the BCBCA requires Court approval. Prior to the mailing of this Proxy Statement/Prospectus, Zymeworks obtained the Interim Order providing for the calling and holding of the Special Meeting, the Dissent Rights and other procedural matters, including, but not limited to: (a) the Required Securityholder Approval; (b) the Dissent Rights for Registered Shareholders; (c) the notice requirements with respect to the Court hearing of the application for the Final Order; (d) the ability of Zymeworks to adjourn or postpone the Special Meeting from time to time in accordance with the terms of the Transaction Agreement without the need

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for additional approval of the Court; and (e) the Record Date for the Zymeworks Securityholders entitled to notice of and to vote at the Special Meeting. A copy of the Interim Order is attached hereto as Appendix D. A copy of Zymeworks’ Notice of Hearing of Petition is attached hereto as Appendix E.

Subject to the terms of the Transaction Agreement, and if the Redomicile Resolution is approved by the Zymeworks Securityholders at the Special Meeting in the manner required by the Interim Order, Zymeworks intends to make an application to the Court for the Final Order. The Interim Order provides for a Final Order approving the Redomicile Transactions to be heard via Microsoft Teams at the courthouse at 800 Smithe Street, Vancouver, British Columbia at 9:45 a.m. on October 12, 2022, or as soon thereafter as counsel may be heard, or at any other date and time and by any other method as the Court may direct. Any Zymeworks Securityholder or other interested party who wishes to participate, appear, or to be represented, and to present evidence or arguments at the hearing must file and serve a Response to Petition in the form prescribed by the Supreme Court Civil Rules (British Columbia) together with any evidence or materials that such party intends to present to the Court, on or before 4:00 p.m. (Vancouver time) on October 7, 2022, all as set out in the Interim Order and Notice of Hearing of Petition. Service of such notice shall be effected by service upon the solicitors of Zymeworks: Blake, Cassels & Graydon LLP, Suite 2600 – 595 Burrard Street, Vancouver, British Columbia, V7X 1L3, Attention: Sean Boyle and Alexandra Luchenko. In the event that the hearing is postponed, adjourned or rescheduled then, subject to further direction of the Court, only those persons having previously served a Response to Petition in compliance with the Interim Order will be given notice of the adjournment or postponement, or the new date. Participation in the Court hearing of the application for the Final Order, including who may participate and present evidence or argument and the procedure for doing so, is subject to the terms of the Interim Order and any subsequent direction of the Court.

The Court has broad discretion under the BCBCA when making orders with respect to plans of arrangement and that the Court will consider at the hearing to obtain the Final Order, among other things, the fairness and reasonableness of the Redomicile Transactions, both from a substantive and a procedural point of view. The Court may approve the Redomicile Transactions either as proposed or as amended in any manner the Court may direct, subject to compliance with such terms and conditions, if any, as the Court thinks fit. Depending upon the nature of any amendments to the plan of arrangement required by the Court, Zymeworks may determine not to proceed with the Redomicile Transactions.

For further information regarding the Court hearing and your rights in connection with the Court hearing, see the form of the Notice of Hearing of Petition attached as Appendix E to this Proxy Statement/Prospectus. The Notice of Hearing of Petition constitutes notice of the Court hearing of the application for the Final Order and is your only notice of the Court hearing.

Stock Exchange Listings

Currently, the Zymeworks Common Shares trade on the NYSE under the symbol “ZYME”. Immediately prior to the Redomicile Transactions, the shares of Delaware Common Stock will be listed for trading on the NYSE under the symbol “ZYME”. When the Redomicile Transactions are completed, the Zymeworks Common Shares currently listed on the NYSE will cease to be traded on the NYSE and will be deregistered under the U.S. Exchange Act.

Material Canadian Securities Law Matters

The shares of Delaware Common Stock and Exchangeable Shares to be issued pursuant to the Redomicile Transactions will be issued pursuant to an exemption from the prospectus and registration requirements of applicable Canadian Securities Laws under Section 2.11 of NI 45-106 and will generally not be subject to any resale restrictions under applicable Canadian Securities Laws, provided that the following conditions are satisfied: (a) the issuer of such shares, pursuant to Section 2.9 of NI 45-102, is and has been a reporting issuer in a jurisdiction of Canada for the four months immediately preceding the trade (upon completion of the Redomicile Transactions, Parent will be deemed to have been a reporting issuer from the time that Zymeworks became a reporting issuer, satisfying this requirement); (b) the trade is not a control distribution; (c) no unusual effort is made to prepare the market or to create a demand for the security that is the subject of the trade; (d) no

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extraordinary commission or consideration is paid to a person or company in respect of the trade; (e) if the selling securityholder is an insider or officer of the issuer, the selling securityholder has no reasonable grounds to believe that the issuer is in default of securities legislation (each as set out in Section 2.6(3) of NI 45-102); and (f) such holder is not a person or company engaged in or holding itself out as engaging in the business of trading securities or such trade is made in accordance with applicable dealer registration requirements or in reliance upon an exemption from such requirements. Zymeworks Shareholders should consult with their own financial and legal advisors with respect to any restrictions on the resale of shares of Delaware Common Stock and Exchangeable Shares received on completion of the Redomicile Transactions.

Ongoing Reporting Obligations

Following completion of the Redomicile Transactions, Parent will be subject to the reporting requirements of the SEC as the successor issuer to Zymeworks. Parent will also become a reporting issuer in each of the provinces and territories of Canada where Zymeworks is currently a reporting issuer and will become subject to the applicable Canadian continuous disclosure requirements in the same manner as Zymeworks is currently.

Consistent with how Zymeworks currently reports, Parent will report consolidated financial results in U.S. dollars and in accordance with U.S. GAAP and will file reports on Form 10-K, 10-Q and 8-K with the SEC and comply with the proxy rules under the U.S. Exchange Act. In accordance with applicable Canadian securities laws, and consistent with Zymeworks’ current practice, Parent will generally file with the relevant Canadian securities regulatory authorities copies of its documents filed with the SEC under the U.S. Exchange Act in order to meet its Canadian continuous disclosure obligations.

Dissent Rights

The following is a summary of the provisions of Division 2 of Part 8 of the BCBCA, as modified by the Plan of Arrangement and the Interim Order, relating to a Registered Shareholder’s Dissent Rights in respect of the Redomicile Resolution. It is not a comprehensive statement of such rights and procedures and is qualified in its entirety by the reference to the full text of Division 2 of Part 8 of the BCBCA (which is attached as Appendix C to this Proxy Statement/Prospectus), as may be modified by the Transaction Agreement and the Interim Order (which are attached as Appendix B and Appendix D to this Proxy Statement/Prospectus, respectively) and any further order of the Court.

The statutory provisions dealing with the right of dissent are technical and complex. Any Zymeworks Shareholder who intends to exercise Dissent Rights should carefully consider and comply with the provisions of Division 2 of Part 8 of the BCBCA, as modified by the Interim Order, the Plan of Arrangement, and any other order of the Court, and seek legal advice. Failure to comply strictly with the provisions of Division 2 of Part 8 of the BCBCA, as may be modified by the Interim Order, the Plan of Arrangement, and any other order of the Court, and to adhere to the procedures established therein, may result in the loss of all rights thereunder.

Pursuant to the Interim Order, Registered Shareholders as of the Record Date have been granted Dissent Rights with respect to the Redomicile Resolution. Each Dissenting Shareholder is entitled to be paid the fair value (determined as of the close of business on the last Business Day before the Redomicile Resolution was adopted at the Special Meeting) of all, but not less than all, of the holder’s Zymeworks Common Shares in accordance with the provisions of Division 2 of Part 8 of the BCBCA, as may be modified by the Interim Order, the Plan of Arrangement, and any other order of the Court, provided that the holder duly dissents with respect to the Redomicile Resolution and the Redomicile Transactions become effective.

Pursuant to Section 238 of the BCBCA, every Registered Shareholder who duly and validly dissents from the Redomicile Resolution in strict compliance with Division 2 of Part 8 of the BCBCA, as may be modified by the Interim Order, the Plan of Arrangement, and any further order of the Court will be entitled to be paid the fair value of the Zymeworks Common Shares held by such Dissenting Shareholder determined as at the point in time immediately before the passing of the Redomicile Resolution.

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Persons who are beneficial owners of Zymeworks Common Shares registered in the name of a broker, bank, trust company or other Intermediary or nominee who wish to dissent should be aware that only Registered Shareholders are entitled to exercise Dissent Rights. Accordingly, a Beneficial Shareholder desiring to exercise this right must make arrangements for the Zymeworks Common Shares beneficially owned by such Zymeworks Shareholder to be registered in the Zymeworks Shareholder’s name prior to the time the Dissent Notice is required to be received by Zymeworks, or, alternatively, make arrangements for the registered holder of such Zymeworks Common Shares to dissent on the Zymeworks Shareholder’s behalf. A Zymeworks Shareholder that votes in favor of the Redomicile Resolution will not be entitled to Dissent Rights but a Zymeworks Shareholder’s failure to vote against the Redomicile Resolution will not constitute a waiver of such shareholder’s dissent rights and a vote against the Redomicile Resolution will not be deemed to satisfy notice requirements under the BCBCA with respect to Dissent Rights.

Registered Zymeworks Shareholders who wish to dissent must provide a written objection to the Redomicile Resolution (a “Dissent Notice”) to Zymeworks, c/o Blake, Cassels & Graydon LLP, 595 Burrard Street, Suite 2600, Vancouver BC V7X 1L3, Attention: Sean Boyle and Alexandra Luchenko, which Dissent Notice must be received by October 5, 2022, or such day that is two Business Days immediately preceding the date that any adjournment or postponement of the Special Meeting is reconvened, and must otherwise strictly comply with the dissent procedures prescribed by the BCBCA, as may be modified and supplemented by the Interim Order, the Plan of Arrangement, and any other order of the Court. A copy of the Plan of Arrangement is attached as Exhibit A to the Transaction Agreement, which is set forth in Appendix B to the Proxy Statement/Prospectus. Copies of the text of Division 2 of Part 8 of the BCBCA and the Interim Order are set forth in Appendices C and D, respectively, to the Proxy Statement/Prospectus.

To exercise Dissent Rights, a Registered Shareholder must dissent with respect to all Zymeworks Common Shares of which it is the registered and beneficial owner, except as expressly set forth below. Beneficial Shareholders who wish to exercise Dissent Rights must cause the registered Zymeworks Shareholder holding their Zymeworks Common Shares to deliver the Dissent Notice. A Registered Shareholder that votes in favour of the Redomicile Resolution will not be entitled to Dissent Rights but a Zymeworks Shareholder’s failure to vote against the Redomicile Resolution will not constitute a waiver of such shareholder’s Dissent Rights and a vote against the Redomicile Resolution will not be deemed to satisfy notice requirements under the BCBCA with respect to Dissent Rights.

A Registered Shareholder must prepare a separate Dissent Notice for him, her or itself, if dissenting on his, her or its own behalf, and for each other Beneficial Shareholder who beneficially owns Zymeworks Common Shares registered in the Zymeworks Shareholder’s name and on whose behalf the Registered Shareholder is dissenting; and, if dissenting on its own behalf, must dissent with respect to all of the Zymeworks Common Shares registered in his, her or its name or if dissenting on behalf of a beneficial Zymeworks Shareholder, with respect to all of the Zymeworks Common Shares registered in his, her or its name and beneficially owned by the beneficial Zymeworks Shareholder on whose behalf the Zymeworks Shareholder is dissenting. The Dissent Notice must set out the number of Zymeworks Common Shares in respect of which the Dissent Rights are being exercised (the “Notice Shares”) and: (a) if such Zymeworks Common Shares constitute all of the Zymeworks Common Shares of which the Zymeworks Shareholder is the registered and beneficial owner and the Zymeworks Shareholder owns no other Zymeworks Common Shares beneficially, a statement to that effect; (b) if such Zymeworks Common Shares constitute all of the Zymeworks Common Shares of which the Registered Shareholder is both the registered and beneficial owner, but the Registered Shareholder beneficially owns additional Zymeworks Common Shares, a statement to that effect and the names of the Registered Shareholders of those other Zymeworks Common Shares, the number of Zymeworks Common Shares held by each such Registered Shareholder and a statement that written notices of dissent are being or have been sent with respect to such other Zymeworks Common Shares; or (c) if the Dissent Rights are being exercised by a Registered Shareholder who is not the Beneficial Shareholder, a statement to that effect and the name and address of the Beneficial Shareholder and a statement that the Registered Shareholder is dissenting with respect to all Zymeworks Common Shares of the Beneficial Shareholder registered in such registered holder’s name.

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The delivery of a Dissent Notice does not deprive a Dissenting Shareholder of the right to vote at the Special Meeting on the Redomicile Resolution; however, a Dissenting Shareholder is not entitled to exercise the Dissent Rights with respect to any of his or her Zymeworks Common Shares if the Dissenting Shareholder votes in favour of the Redomicile Resolution. A vote against the Redomicile Resolution, whether in person or by proxy, does not constitute a Dissent Notice.

If the Redomicile Resolution is approved by the Zymeworks Securityholders and if Zymeworks notifies the Dissenting Shareholder of the Company’s intention to act upon the Redomicile Resolution, the Dissenting Shareholder is then required, within one month after Zymeworks gives such notice, to send to Zymeworks the certificates (if any) representing the Notice Shares and a written statement that requires Zymeworks to purchase all of the Notice Shares (including a written statement prepared in accordance with Section 244(1)(c) of the BCBCA if the dissent is being exercised by a Registered Shareholder on behalf of a Beneficial Shareholder), whereupon, subject to the provisions of the BCBCA relating to the termination of Dissent Rights, the Zymeworks Shareholder becomes a Dissenting Shareholder, and is bound to sell, and Zymeworks is bound to purchase, those Zymeworks Common Shares. Such Dissenting Shareholder may not vote or exercise or assert any rights of a Zymeworks Shareholder in respect of such Notice Shares, other than the rights set forth in Division 2 of Part 8 of the BCBCA, as modified by the Interim Order, the Plan of Arrangement, and any other order of the Court.

The Dissenting Shareholder and Zymeworks may agree on the payout value of the Notice Shares; otherwise, either party may apply to the Court to determine the fair value of the Notice Shares. There is no obligation on Zymeworks to make an application to the Court. If such Dissenting Shareholder does not reach an agreement with Zymeworks, such Dissenting Shareholder, or Zymeworks, may apply to the Court, and the Court may:

After a determination of the payout value of the Notice Shares, the Dissenting Shareholder must then promptly be paid that amount. There can be no assurance that the amount a Dissenting Shareholder may receive as fair value for its Zymeworks Common Shares will be more than or equal to the consideration under the Redomicile Transactions.

Dissenting Shareholders who:

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provided, however, that in no case shall Zymeworks, Parent or the Depositary or any other Person be required to recognize Zymeworks Shareholders who exercise Dissent Rights as Zymeworks Shareholders after the Effective Time.

A Dissenting Shareholder loses his or her Dissent Right if, before full payment is made for the Notice Shares, Zymeworks abandons the corporate action that has given rise to the Dissent Right (namely, the Redomicile Transactions), a court permanently enjoins the action, or the Dissenting Shareholder withdraws the Dissent Notice with Zymeworks’ written consent. When these events occur, Zymeworks must return the share certificates (if any) to the Dissenting Shareholder and the Dissenting Shareholder regains the ability to vote and exercise shareholder rights.

In no circumstances will Zymeworks, the Depositary or any other person be required to recognize a person as a Dissenting Shareholder unless such person is the holder of the Zymeworks Common Shares in respect of which Dissent Rights are purported to be exercised immediately prior to the Effective Time of the Redomicile Transactions; (i) if such person has voted or instructed a proxyholder to vote the Notice Shares in favour of the Redomicile Resolution; and (ii) unless such person has strictly complied with the procedures for exercising Dissent Rights set out in Division 2 of Part 8 of the BCBCA, as modified by the Interim Order, the Plan of Arrangement, and any other order of the Court, and does not withdraw such person’s Dissent Notice prior to the effective time of the Arrangement.

In no event will Zymeworks, Parent or any other Person be required to recognize a Dissenting Shareholder as the holder of any Zymeworks Common Shares in respect of which Dissent Rights have been validly exercised and not withdrawn at and after the Effective Time, and at the Effective Time the names of such Dissenting Shareholders will be deleted from the central securities register of Zymeworks as at the Effective Time.

Dissent Rights with respect to Notice Shares will terminate and cease to apply to the Dissenting Shareholder if, before full payment is made for the Notice Shares, the Arrangement in respect of which the Dissent Notice was sent is abandoned or by its terms will not proceed, a court permanently enjoins or sets aside the corporate action approved by the Redomicile Resolution, the Dissenting Shareholder votes in favour of the Redomicile Resolution, or the Dissenting Shareholder withdraws the Dissent Notice with Zymeworks’ written consent. If any of these events occur, Zymeworks must return the share certificates representing the Zymeworks Common Shares to the Dissenting Shareholder and the Dissenting Shareholder regains the ability to vote and exercise its rights as a Shareholder.

If a Dissenting Shareholder fails to strictly comply with the requirements of the Dissent Rights set out in the Interim Order, it will lose its Dissent Rights, Zymeworks will return to the Dissenting Shareholder the certificates representing the Notice Shares that were delivered to Zymeworks, if any, and if the Arrangement is completed, that Dissenting Shareholder will be deemed to have participated in the Arrangement on the same terms as a Zymeworks Shareholder.

The discussion above is only a summary of the Dissent Rights, which are technical and complex. A Zymeworks Shareholder who intends to exercise Dissent Rights should carefully consider and comply with the provisions of Division 2 of Part 8 of the BCBCA, as may be modified by the Interim Order, the Plan of Arrangement, and any other order of the Court. Zymeworks suggests that any Zymeworks Shareholder wishing to avail themselves of the Dissent Rights seek their own legal advice as failure to comply strictly with the applicable provisions of the BCBCA, as may be modified by the Plan of Arrangement, Interim Order and the Final Order may result in the loss of all Dissent Rights. Dissenting Shareholders should note that the exercise of Dissent Rights can be a complex, time-consuming and expensive process.

For a general summary of certain income tax implications to a Dissenting Shareholder, see section titled “Material Canadian Federal Income Tax Considerations”.

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SUMMARY OF THE TRANSACTION AGREEMENT

The following is a summary description of certain material provisions of the Transaction Agreement, is not comprehensive and is qualified in its entirety by reference to the complete text of the Transaction Agreement, copies of which are available under Zymeworks’ profile on SEDAR at www.sedar.com, its profile on the SEC’s website at www.sec.gov or its website at www.zymeworks.com.

On August 18, 2022, Zymeworks, Parent, ExchangeCo and Callco entered into the Restated and Amended Transaction Agreement, pursuant to which they agreed that, subject to the terms and conditions set forth in the Transaction Agreement, Parent will acquire, directly or indirectly through ExchangeCo (a direct wholly-owned subsidiary of Callco), all outstanding Zymeworks Common Shares pursuant to the Arrangement. Upon completion of the Arrangement, Zymeworks Shareholders will hold one share of Delaware Common Stock or one Exchangeable Share, as applicable, for each Zymeworks Common Share owned immediately prior to the Arrangement (with the aggregate number of Exchangeable Shares that is equal to or less than the Exchangeable Share Cap). If the Exchangeable Share Cap is reached, then the Exchangeable Shares shall be allocated proportionally among the applicable Eligible Holders based on the number of Exchangeable Shares requested and rounded down to the nearest whole share in respect of each Eligible Holder, in which case, the Eligible Holder will also be issued Delaware Common Stock under a Mixed Election. The Share Trustee will hold one share of the Special Voting Stock, which will be held by the Share Trustee under the terms of the Trust Agreement. The Exchangeable Shares will be exchangeable for Delaware Common Stock in accordance with the Exchangeable Share Provisions.

Representations and Warranties

Except for its status as the contractual document that establishes and governs the legal relations among Zymeworks, Parent, ExchangeCo and Callco with respect to the Arrangement, the Transaction Agreement is not a source of factual, business or operational information about Zymeworks, Parent, ExchangeCo or Callco.

The Transaction Agreement contains representations and warranties made by each of Zymeworks, Parent, ExchangeCo and Callco to each other. The representations and warranties relate to, among other things: (a) the due organization, existence and power and authority of each of Zymeworks, Parent, ExchangeCo and Callco to own, lease and operate their respective properties and to carry on their respective business; (b) the corporate power and authority of each of Zymeworks, Parent, ExchangeCo and Callco to enter into the Transaction Agreement and perform their respective obligations thereunder; and (c) the execution and delivery of the Transaction Agreement by each of Zymeworks, Parent, ExchangeCo and Callco, and the performance by each of them of their respective obligations thereunder and the completion of the Arrangement not resulting in a violation, conflict or default under their respective constating documents or any applicable Law, or resulting in the creation of a lien against their respective properties and assets.

Conditions Precedent to the Arrangement

The obligations of Zymeworks, Parent, ExchangeCo and Callco to consummate the Arrangement and the other transactions contemplated under the Transaction Agreement are subject to the satisfaction of the following conditions (which may be waived, to the extent permitted by Law, by Zymeworks):

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Other Covenants

The Transaction Agreement provides that:

Post-Arrangement Matters

As soon as practicable following the Effective Time and Zymeworks’ election to be treated as a private corporation for Canadian tax purposes, Zymeworks, Parent, ExchangeCo and Callco shall use reasonable efforts,

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and shall take such corporate steps and actions, as may be necessary or desirable to effect and implement the following transactions in the order set forth below:

Termination of the Transaction Agreement

The Transaction Agreement may be terminated prior to the Effective Time upon written notice by Zymeworks to Parent, ExchangeCo and Callco.

Governing Law

The Transaction Agreement is governed by and construed in accordance with the Laws of the Province of British Columbia and other federal Laws of Canada applicable in British Columbia without giving effect to any choice of law or conflict of law provision or rule (whether of the Province of British Columbia or any other jurisdiction) that would cause the application of the law of any jurisdiction other than the Province of British Columbia.

Amendment

The Transaction Agreement may only be amended upon the written agreement of Zymeworks, Parent, ExchangeCo and Callco.

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such dividends or other distributions will be paid out of money, assets or property of ExchangeCo properly applicable to the payment of dividends or other distributions, or out of authorized but unissued shares of ExchangeCo, as applicable; provided that the ExchangeCo board of directors may determine to adjust the Exchangeable Share Exchange Ratio as provided in the Exchangeable Share Provisions in lieu of paying any such dividend or other distribution on the Exchangeable Shares; and provided further that the Exchangeable Share Exchange Ratio will be so adjusted only to the extent the ExchangeCo board of directors determines in good faith and in its sole discretion that ExchangeCo would be liable for any unrecoverable tax as a result of paying any such dividend or distribution. The holders of Exchangeable Shares will not be entitled to any dividends or other distributions other than or in excess of the foregoing.

The record date for the determination of the holders of Exchangeable Shares entitled to receive payment of, and the payment date for, any dividend or other distribution declared on the Exchangeable Shares will be the same dates as the record date and payment date, respectively, for the corresponding dividend or other distribution declared on the Delaware Common Stock (but excluding any distributions pursuant to a Preferred Stock Rights Agreement).

If on any payment date for any dividends or other distributions declared on the Exchangeable Shares, the dividends or other distributions are not paid in full on all of the Exchangeable Shares then outstanding, any such dividends or other distributions that remain unpaid will be paid on a subsequent date or dates determined by the ExchangeCo board of directors on which ExchangeCo has sufficient monies, assets or property properly applicable to the payment of such dividends or other distributions.

The ExchangeCo board of directors is required to determine, in good faith and in its sole discretion (with the assistance of such financial or other advisors as the ExchangeCo board of directors may determine), “economic equivalence” for the purposes of the Exchangeable Share Provisions and each such determination will be conclusive and binding on ExchangeCo and its shareholders. In making each such determination, a number of factors set out in the Exchangeable Share Provisions will, without excluding other factors determined by the ExchangeCo board of directors to be relevant, be considered by the ExchangeCo board of directors.

Certain Restrictions

So long as any of the Exchangeable Shares are outstanding, ExchangeCo will not at any time without, but may at any time with, the approval of the holders of the Exchangeable Shares given as specified in the Exchangeable Share Provisions:

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The restrictions listed in paragraphs (a), (b), (c) and (d) above will not apply if, in connection with all dividends or other distributions declared and paid on the Delaware Common Stock (but excluding any distributions pursuant to a Preferred Stock Rights Agreement): (i) all dividends or other distributions on the outstanding Exchangeable Shares have been declared and paid in full on the Exchangeable Shares, or (ii) the Exchangeable Share Exchange Ratio has been adjusted in accordance with the Exchangeable Share Provisions, in each case, prior to or as at the date of any such event referred to in paragraphs (a), (b), (c) or (d) above.

Exchangeable Share Exchange Ratio Adjustments

The Exchangeable Share Exchange Ratio may be cumulatively adjusted from time to time after the Effective Date by increasing the Exchangeable Share Exchange Ratio on each date after the Effective Date on which the Parent board of directors pays any dividend or other distribution on the Delaware Common Stock by an amount, rounded to the nearest five decimal places, equal to (a)(i) the amount of such dividend or other distribution (which, in the case of a non-cash dividend, shall equal the fair value as determined by the ExchangeCo board of directors in good faith and in its sole discretion), expressed on a per Delaware Common Stock basis, multiplied (ii) by the Exchangeable Share Exchange Ratio in effect on the Business Day (for purposes of this section, as defined in the Exchangeable Share Provisions) immediately preceding the record date set for such dividend or other distribution, divided by (b) the Current Market Price on the record date set for such dividend or other distribution, and any such adjustment shall be determined by the ExchangeCo board of directors in good faith and in its sole discretion and any such determination by the ExchangeCo board of directors shall be conclusive and binding; provided, however, that the Exchangeable Share Exchange Ratio will be so adjusted only to the extent that the ExchangeCo board of directors determines in good faith and in its sole discretion that ExchangeCo would be liable for any unrecoverable tax as a result of paying any such dividend or distribution and determines to adjust the Exchangeable Share Exchange Ratio in lieu of paying an Equivalent Dividend on the Exchangeable Shares as contemplated by the Exchangeable Share Provisions.

Distribution on Liquidation and Associated Call Right

Subject to applicable Laws and the due exercise by Callco of the Liquidation Call Right, in the event of the liquidation, dissolution or winding-up of ExchangeCo, whether voluntary or involuntary, or any other distribution of the assets of ExchangeCo among its shareholders for the purpose of winding up its affairs, a holder of Exchangeable Shares will be entitled to receive from the assets of ExchangeCo in respect of each Exchangeable Share held by such holder on the effective date of such liquidation, dissolution, winding-up or other distribution (the “Liquidation Date”), before any distribution of any part of the assets of ExchangeCo among the holders of the common shares of ExchangeCo or any other shares ranking junior to the Exchangeable Shares, an amount per share (the “Liquidation Amount”) equal to the Exchangeable Share Price on the last Business Day prior to the Liquidation Date, which will be satisfied in full by ExchangeCo delivering or causing to be delivered to such holder of Exchangeable Shares the Exchangeable Share Consideration representing the Liquidation Amount for each Exchangeable Share held by such holder; provided that, for the avoidance of doubt, upon such a liquidation, dissolution or winding-up of ExchangeCo, a holder of Exchangeable Shares will still have the rights set forth under “Retraction of Exchangeable Shares and Associated Call Right”.

Pursuant to the Support Agreement, Callco has the overriding right (the “Liquidation Call Right”), in the event of and notwithstanding the proposed liquidation, dissolution or winding-up of ExchangeCo or any other distribution of the assets of ExchangeCo among its shareholders for the purpose of winding up its affairs, to

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purchase from all but not less than all of the holders of Exchangeable Shares (other than Parent or its subsidiaries (in this section, as defined in the Exchangeable Share Provisions)) on the Liquidation Date, all but not less than all of the Exchangeable Shares held by each such holder on payment by Callco to each such holder of an amount per share equal to the Exchangeable Share Price (payable in the form of the Exchangeable Share Consideration) on the last Business Day prior to the Liquidation Date (the “Liquidation Call Purchase Price”). In the event of the exercise of the Liquidation Call Right by Callco, each holder of Exchangeable Shares (other than Parent and its subsidiaries) will be obligated to sell all of the Exchangeable Shares held by the holder to Callco on the Liquidation Date upon payment by Callco to such holder of the Liquidation Call Purchase Price for each such share, and ExchangeCo will have no obligation to pay any Liquidation Amount to the holders of such shares so purchased. The Liquidation Call Purchase Price will be satisfied in full by Callco depositing or causing to be deposited with the ExchangeCo Transfer Agent, on or before the Liquidation Date, the Exchangeable Share Consideration representing the aggregate Liquidation Call Purchase Price less any amounts withheld on account of taxes.

To exercise the Liquidation Call Right, Callco must notify the ExchangeCo Transfer Agent, as agent for the holders of Exchangeable Shares, and ExchangeCo of its intention to exercise such right (a) in the case of a voluntary liquidation, dissolution or winding-up of ExchangeCo or any other voluntary distribution of the assets of ExchangeCo among its shareholders for the purpose of winding up its affairs, at least fifteen (15) Business Days before the Liquidation Date, or (b) in the case of an involuntary liquidation, dissolution or winding-up of ExchangeCo or any other involuntary distribution of the assets of ExchangeCo among its shareholders for the purpose of winding up its affairs, at least five (5) Business Days before the Liquidation Date. The ExchangeCo Transfer Agent will notify the holders of Exchangeable Shares as to whether or not Callco has exercised the Liquidation Call Right forthwith after the expiry of the period during which the same may be exercised by Callco. If Callco exercises the Liquidation Call Right, then on the Liquidation Date, Callco will purchase and the holders of the Exchangeable Shares (other than Parent or its subsidiaries) will sell, all of the Exchangeable Shares held by such holders on such date for a price per share equal to the Liquidation Call Purchase Price (payable in the form of the Exchangeable Share Consideration). If Callco does not notify the Exchange Transfer Agent and ExchangeCo of its intention to exercise the Liquidation Call Right in the manner and timing described above, each holder of Exchangeable Shares will, at the holder’s discretion, be entitled to demand (by way of notice given to the Company) that Callco exercise the Liquidation Call Right in respect of the shares covered by the notice, in which case, Callco shall be deemed of have exercised the Liquidation Call Right and will be bound thereby.

Retraction of Exchangeable Shares and Associated Call Right

Subject to applicable Laws and the due exercise by Callco of the Retraction Call Right, a holder of Exchangeable Shares will be entitled at any time to require ExchangeCo to redeem any or all Exchangeable Shares registered in the name of such holder and for an amount per share equal to the Exchangeable Share Price on the last Business Day prior to the Retraction Date (the “Retraction Price”), which price will be satisfied in full by ExchangeCo delivering or causing to be delivered to such holder the Exchangeable Share Consideration representing the Retraction Price. A holder of Exchangeable Shares must give notice of a request to redeem or purchase, as applicable, by presenting and surrendering to ExchangeCo (or to the ExchangeCo Transfer Agent) the certificate(s) representing the Exchangeable Shares that the holder desires to have ExchangeCo redeem, together with (a) such documents, instruments and payments as the ExchangeCo Transfer Agent and ExchangeCo may reasonably require and (b) a duly executed request (the “Retraction Request”) in accordance with the Exchangeable Share Provisions: (i) specifying that the holder desires to have all or any number specified therein of the Exchangeable Shares represented by such certificate(s) (the “Retracted Shares”) redeemed by ExchangeCo; (ii) stating the Business Day on which the holder desires to have ExchangeCo redeem the Retracted Shares (the “Retraction Date”), provided that the Retraction Date will not be less than ten (10) Business Days nor more than fifteen (15) Business Days after the date on which the Retraction Request is received by ExchangeCo, and further provided that, in the event that no such Business Day is specified by the holder in the Retraction Request, the Retraction Date will be deemed to be the fifteenth (15th) Business Day after the date on which the Retraction Request is received by ExchangeCo, subject to the Exchangeable Share Provisions; and (iii) acknowledging the overriding Retraction Call Right of Callco to purchase all but not less than all the Retracted Shares directly from the holder and that the Retraction Request will be deemed to be a

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revocable offer by the holder to sell the Retracted Shares to Callco in accordance with the Retraction Call Right on the Retraction Date for the Retraction Call Right Purchase Price and on the other terms and conditions set out in the Exchangeable Share Provisions.

In accordance with the Exchangeable Share Provisions, in the event that a holder of Exchangeable Shares delivers a Retraction Request, Callco will have the overriding right (the “Retraction Call Right”), notwithstanding the proposed redemption of the Exchangeable Shares, to purchase from such holder on the Retraction Date all but not less than all of the Retracted Shares held by such holder on payment by Callco of an amount per share equal to the Exchangeable Share Price applicable on the last Business Day prior to the Retraction Date (the “Retraction Call Right Purchase Price”), which price will be satisfied in full by Callco delivering or causing to be delivered to such holder the Exchangeable Share Consideration representing the Retraction Call Right Purchase Price less any amounts withheld on account of taxes.

Upon receipt by ExchangeCo of a Retraction Request, ExchangeCo will immediately notify Callco and will provide Callco with a copy of the Retraction Request. To exercise its Retraction Call Right, Callco must notify ExchangeCo in writing of its determination to do so within five (5) Business Days after ExchangeCo notifies Callco. If Callco does not so notify ExchangeCo within such five (5) Business Day period, ExchangeCo will notify the holder as soon as possible thereafter that Callco did not exercise the Retraction Call Right. If Callco delivers a Retraction Call Notice within such five (5) Business Day period and duly exercises its Retraction Call Right, the obligation of ExchangeCo to redeem the Retracted Shares will terminate and, provided that the Retraction Request is not revoked by the holder of such Retracted Shares in the manner described below), Callco will purchase from such holder and such holder will sell to Callco on the Retraction Date the Retracted Shares for an amount per share equal to the Retraction Call Right Purchase Price less any amounts withheld on account of taxes. Provided that the aggregate Retraction Call Right Purchase Price has been deposited with the ExchangeCo Transfer Agent, the closing of the purchase and sale of the Retracted Shares pursuant to the Retraction Call Right will be deemed to have occurred as at the close of business on the Retraction Date.

A holder of Exchangeable Shares who has made a Retraction Request may, by notice in writing given by the holder to ExchangeCo before the close of business on the Business Day immediately preceding the Retraction Date, withdraw such Retraction Request, in which event such Retraction Request will be null and void and the revocable offer constituted by the Retraction Request to sell such Exchangeable Shares to Callco pursuant to the exercise of the Retraction Call Right will be deemed to have been revoked.

If Callco does not notify the ExchangeCo Transfer Agent and ExchangeCo of its intention to exercise the Retraction Call Right in the manner and timing described above, each holder of Exchangeable Shares will, at the holder’s discretion, be entitled to demand (by way of notice given to the Company) that Callco exercise the Retraction Call Right in respect of the shares covered by the notice, in which case, Callco shall be deemed of have exercised the Retraction Call Right and will be bound thereby.

Redemption of Exchangeable Shares and Associated Call Right

Subject to applicable Laws and the due exercise by Callco of the Redemption Call Right, ExchangeCo will on the Redemption Date redeem all but not less than all of the then outstanding Exchangeable Shares (other than Exchangeable Shares held by Parent and its subsidiaries) for an amount per share (the “Redemption Price”) equal to the Exchangeable Share Price on the last Business Day prior to the Redemption Date, which price will be satisfied in full by ExchangeCo delivering or causing to be delivered to each holder of Exchangeable Shares the Exchangeable Share Consideration for each Exchangeable Share held by such holder.

The “Redemption Date” is the date, if any, established by the ExchangeCo board of directors for the redemption by ExchangeCo of all but not less than all of the outstanding Exchangeable Shares, which date will be on the Sunset Date unless:

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Pursuant to the Support Agreement, Callco has the overriding right (the “Redemption Call Right”), notwithstanding the proposed redemption of the Exchangeable Shares by ExchangeCo, to purchase from all but not less than all of the holders of Exchangeable Shares (other than Parent or any of its subsidiaries) on the Redemption Date all but not less than all of the Exchangeable Shares held by each such holder on payment by Callco of an amount per share equal to the Exchangeable Share Price on the last Business Day prior to the Redemption Date (the “Redemption Call Purchase Price”). In the event of the exercise of the Redemption Call Right by Callco, each holder of Exchangeable Shares will be obligated to sell all of the Exchangeable Shares held by the holder to Callco on the Redemption Date on payment by Callco to the holder of the Redemption Call Purchase Price for each such share, and ExchangeCo will have no obligation to redeem, or pay the Redemption Price otherwise payable by ExchangeCo, in respect of the shares so purchased. The Redemption Call Purchase Price will be satisfied in full by Callco depositing or causing to be deposited with the ExchangeCo Transfer Agent, on or before the Redemption Date, the Exchangeable Share Consideration representing the aggregate Redemption Call Purchase Price less any amounts withheld on account of taxes.

To exercise the Redemption Call Right, Callco must notify the ExchangeCo Transfer Agent, as agent for the holders of Exchangeable Shares, and ExchangeCo of its intention to exercise such right (a) in the case of a redemption occurring in connection with a Parent Control Transaction, on or before the Redemption Date, and (b) in any other case, at least fifteen (15) Business Days before the Redemption Date. The ExchangeCo Transfer Agent will notify the holders of Exchangeable Shares as to whether or not Callco has exercised the Redemption Call Right forthwith after the expiry of the period during which the same may be exercised by Callco. If Callco exercises the Redemption Call Right, Callco will purchase and the holders of the Exchangeable Shares (other than Parent or its subsidiaries) will sell, on the Redemption Date, all of the Exchangeable Shares held by such holders on such date for a price per share equal to the Redemption Call Purchase Price (payable in the form of the Exchangeable Share Consideration).

If Callco does not notify the Transfer Agent and ExchangeCo of its intention to exercise the Redemption Call Right in the manner and timing described above, each holder of Exchangeable Shares will, at the holder’s discretion, be entitled to demand (by way of notice given to the Company) that Callco exercise the Redemption Call Right in respect of the shares covered by the notice, in which case Callco shall be deemed of have exercised the Redemption Call Right and will be bound thereby.

Change of Law Call Right

Pursuant to the Support Agreement, Callco has the overriding right (the “Change of Law Call Right”), in the event of a Change of Law, to purchase from all but not less than all of the holders of Exchangeable Shares (other than Parent or its subsidiaries) on the Change of Law Call Date all but not less than all of the Exchangeable Shares held by each such holder on payment by Callco of an amount per share (the “Change of Law Call Purchase Price”) equal to the Exchangeable Share Price applicable on the last Business Day prior to the date on

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which ExchangeCo acquires the Exchangeable Shares pursuant to the exercise of the Change of Law Call Right (the “Change of Law Call Date”). In the event of the exercise of the Change of Law Call Right by Callco, each such holder of Exchangeable Shares will be obligated to sell all of the Exchangeable Shares held by the holder to Callco on the Change of Law Call Date upon payment by Callco to such holder of the Change of Law Call Purchase Price (payable in the form of Exchangeable Share Consideration). The Change of Law Call Purchase Price will be satisfied in full by Callco depositing or causing to be deposited with the ExchangeCo Transfer Agent, on or before the Change of Law Call Date, the Exchangeable Share Consideration representing the total Change of Law Call Purchase Price less any amounts withheld on account of taxes.

To exercise the Change of Law Call Right, Callco must notify the ExchangeCo Transfer Agent, as agent for the holders of Exchangeable Shares, and ExchangeCo of its intention to exercise such right at least fifteen (15) days before the Change of Law Call Date. The ExchangeCo Transfer Agent will notify the holders of Exchangeable Shares that Callco has exercised the Change of Law Call Right forthwith after receiving notice of such exercise. If Callco exercises the Change of Law Call Right, Callco will purchase, and the holders of the Exchangeable Shares will sell, on the Change of Law Call Date, all of the Exchangeable Shares then outstanding for a price per share equal to the Change of Law Call Purchase Price.

Voting Rights

Except as required by applicable Laws and in respect of certain matters as further described in the Exchangeable Share Provisions, the holders of the Exchangeable Shares will not be entitled as such to receive notice of or to attend any meeting of the shareholders of ExchangeCo or to vote at any such meeting. Without limiting the generality of the foregoing, the holders of the Exchangeable Shares will not be entitled to class votes except as required by applicable Law.

Amendment and Approval

Any approval required to be given by the holders of the Exchangeable Shares to add to, change or remove any right, privilege, restriction or condition attaching to the Exchangeable Shares or any other matter requiring the approval or consent of the holders of the Exchangeable Shares in accordance with applicable Laws will be deemed to have been sufficiently given if it has been given in accordance with applicable Laws, subject to, in certain circumstances as provided for in the Exchangeable Share Provisions, a minimum requirement that such approval be evidenced by a resolution passed by not less than two-thirds of the votes cast on such resolution at a meeting of holders of Exchangeable Shares duly called and held at which the holders of at least 10% of the outstanding Exchangeable Shares at that time are present in person or represented by proxy.

Tax Treatment

The treatment of Exchangeable Shares for U.S. federal income tax purposes is uncertain. Holders of Exchangeable Shares should consult their own advisors regarding the tax consequences of owning and disposition of Exchangeable Shares.

Support Agreement

The following is a summary description of certain material provisions that will be contained in the Support Agreement, is not comprehensive and is qualified in its entirety by reference to the complete text of the Support Agreement the form of which is attached as Exhibit C to the Transaction Agreement, which is set forth in Appendix B to the Proxy Statement/Prospectus. The Support Agreement will be filed on SEDAR and EDGAR following closing of the Arrangement, available under Zymeworks’ profile on SEDAR at www.sedar.com, its profile on the SEC’s website at www.sec.gov or its website at www.zymeworks.com.

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Covenants regarding Exchangeable Shares

Pursuant to the Support Agreement, Parent will agree that, so long as any Exchangeable Shares not owned by Parent or its subsidiaries (as defined in such agreement) are outstanding, Parent will, among other things:

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Economic Equivalence

In order to protect the economic equivalence of the Exchangeable Shares, the Support Agreement will provide that, so long as any Exchangeable Shares not owned by Parent or its subsidiaries are outstanding:

unless, in each case, ExchangeCo issues or distributes the economic equivalent on a per share basis of such rights, options, warrants, securities, shares, evidences of indebtedness or other assets simultaneously to holders of the Exchangeable Shares, including, without limitation, an adjustment to the Exchangeable Share Exchange Ratio in accordance with the terms of the Exchangeable Share Provisions;

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unless, in each case, the same or an economically equivalent change is made simultaneously to, or in the rights of the holders of, the Exchangeable Shares.

The ExchangeCo board of directors will determine, in good faith and in its sole discretion (with the assistance of such financial or other advisors as the ExchangeCo board of directors may determine), “economic equivalence” for the purposes of any event referred to in paragraphs (a) or (b) above and each such determination will be conclusive and binding on Parent. Pursuant to the Support Agreement, ExchangeCo will agree that, to the extent required, upon due notice from Parent, ExchangeCo will use commercially reasonable efforts to take or cause to be taken such steps as may be necessary for the purposes of ensuring that appropriate dividends are paid or other distributions are made by ExchangeCo, or the Exchangeable Share Exchange Ratio is adjusted, in order to implement the required economic equivalence with respect to the Delaware Common Stock and Exchangeable Shares.

Tender Offers

The Support Agreement will provide that, in the event that a tender offer, share exchange offer, issuer bid, takeover bid or similar transaction with respect to Delaware Common Stock (an “Offer”) is proposed by Parent or is proposed to Parent or its stockholders and is recommended by the Parent board of directors, or is otherwise effected or to be effected with the consent or approval of the Parent board of directors, and the Exchangeable Shares are not redeemed by ExchangeCo or purchased by Callco pursuant to the Redemption Call Right, Parent and ExchangeCo will use commercially reasonable efforts to take all such actions and do all such things as are necessary or desirable to enable and permit holders of Exchangeable Shares (other than Parent and its affiliates) to participate in such Offer to the same extent and on an economically equivalent basis as the holders of Delaware Common Stock, without discrimination. Without limiting the generality of the foregoing, Parent and ExchangeCo will use commercially reasonable efforts in good faith to ensure that all holders of Exchangeable Shares may participate in such Offer without being required to retract Exchangeable Shares as against ExchangeCo (or, if so required, to ensure that any such retraction is effective only upon, and is conditional upon, the closing of such Offer and only to the extent necessary to tender or deposit to the Offer).

Ownership of ExchangeCo Shares

The Support Agreement will also provide that, without the prior approval of ExchangeCo and the prior approval of the holders of the Exchangeable Shares given in accordance with the Exchangeable Share Provisions, as long as any outstanding Exchangeable Shares not owned by Parent or any of its affiliates are outstanding, Parent will be and remain the direct or indirect beneficial owner of all issued and outstanding common shares of ExchangeCo and Callco.

Amendments to the Support Agreement

The Support Agreement will provide that, with the exception of changes for the purpose of (a) adding to the covenants of any or all of the parties thereto; (b) evidencing the succession of successors to Parent and the covenants and obligations assumed by such successors; (c) making such amendments or modifications not inconsistent with the Support Agreement as may be necessary or desirable with respect to matters or questions arising thereunder or (d) curing or correcting any ambiguities or defect or inconsistent provision or clerical omission or mistake or manifest errors (provided, in the case of clauses (a), (c) and (d), that the board of directors of each of Parent, ExchangeCo and Callco are of the good faith opinion that such amendments are not prejudicial to the rights or interests of the holders of the Exchangeable Shares), the Support Agreement may not be amended except by agreement in writing executed by Parent, Callco and ExchangeCo and approved by the holders of the Exchangeable Shares given in accordance with the Exchangeable Share Provisions.

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Voting of Exchangeable Shares

Under the Support Agreement, each of Parent and Callco will agree not to, and to cause its affiliates not to, exercise any voting rights which may be exercisable by holders of Exchangeable Shares from time to time with respect to any Exchangeable Shares owned by it or its affiliates in respect of any matter considered at meetings of holders of Exchangeable Shares (including any approval sought from such holders in respect of matters arising under the Support Agreement).

Reimbursement by Parent

Parent shall reimburse ExchangeCo for, and indemnify and hold ExchangeCo harmless against, any expense or liability incurred by ExchangeCo with respect to the Exchangeable Shares.

Trust Agreement

The following is a summary description of certain material provisions that will be contained in the Trust Agreement, and is not comprehensive and is qualified in its entirety by reference to the complete text of the Trust Agreement, the form of which is attached as Exhibit D to the Transaction Agreement, which is set forth in Appendix B to the Proxy Statement/Prospectus. The Trust Agreement will be filed on SEDAR and EDGAR following closing of the Arrangement, available under its profile on SEDAR at www.sedar.com, its profile on the SEC’s website at www.sec.gov or its website at www.zymeworks.com.

The purpose of the Trust Agreement is to create a trust for the benefit of the registered holders from time to time of Exchangeable Shares (other than Parent or affiliates of Parent) (the “Beneficiaries”). The Share Trustee will hold the Special Voting Stock in order to enable the Share Trustee to exercise the voting rights attached thereto and will hold the Exchange Right and the Automatic Exchange Right (as such terms are defined in the Trust Agreement) in order to enable the Share Trustee to exercise or enforce such rights, in each case as trustee for and on behalf of the Beneficiaries.

Voting Rights

Pursuant to the Trust Agreement, Parent will issue to and deposit with the Share Trustee the Special Voting Stock to be held of record by the Share Trustee as trustee for and on behalf of, and for the use and benefit of, the Beneficiaries and in accordance with the provisions of the Trust Agreement.

Under the Trust Agreement, the Share Trustee shall be entitled to exercise all of the voting rights, including the right to consent to or vote in person or by proxy, attaching to the Special Voting Stock on any matters, question, proposal or proposition that may properly come before all meetings of stockholders of Parent or in connection with a Parent Consent (as such term is defined in the Trust Agreement).

With respect to all meetings of stockholders of Parent at which stockholders of Parent are entitled to vote and with respect to all Parent Consents, each Beneficiary shall be entitled to instruct the Share Trustee to cast and exercise, in the manner instructed, the number of votes to which a holder of one share of Delaware Common Stock is entitled with respect to such matter, proposition or question for each Exchangeable Share owned of record by such Beneficiary at the close of business on the record date established by Parent or by applicable law, multiplied by the Exchangeable Share Exchange Ratio, and in respect of each Beneficiary, rounded down to the nearest whole vote.

The aggregate voting rights attached to the Special Voting Stock at a meeting of stockholders of Parent at which stockholders of Parent are entitled to vote shall consist of a number of votes equal to one vote per outstanding Exchangeable Share from time to time not owned by Parent and its affiliates on the record date established by Parent, multiplied by the Exchangeable Share Exchange Ratio, and in respect of each Beneficiary, rounded down to the nearest whole vote, and for which the Share Trustee shall have received voting instructions from the holder of the Exchangeable Share.

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The Share Trustee will exercise each vote attached to the Special Voting Stock only as directed by the relevant holder and, in the absence of instructions from a holder as to voting, the Share Trustee will not exercise voting rights with respect to such Exchangeable Share. A holder may, upon instructing the Share Trustee, obtain a proxy from the Share Trustee entitling the holder to vote directly at the relevant meeting the votes attached to the Special Voting Stock to which the holder is entitled.

The Share Trustee will send to the Beneficiaries by mail or electronic transmission the notice of each meeting or Parent Consent at which the stockholders of Parent are entitled to vote, together with the related meeting materials and a statement as to the manner in which the holder may instruct the Share Trustee to exercise the votes attaching to the Special Voting Stock, at the same time as Parent sends such notice and materials to the stockholders of Parent. The Share Trustee will also send to the holders of Exchangeable Shares copies of all information statements, interim and annual financial statements, reports and other materials sent by Parent to the stockholders of Parent at the same time as such materials are sent to the stockholders of Parent. To the extent such materials are provided to the Share Trustee by Parent, the Share Trustee will also send to the holders all materials sent by third parties to stockholders of Parent generally, including dissident proxy circulars and tender and exchange offer circulars, as soon as possible after such materials are first sent to the stockholders of Parent.

All rights of a holder of Exchangeable Shares to exercise votes attached to the Special Voting Stock will cease upon the exchange of such holder’s Exchangeable Shares for Delaware Common Stock.

ExchangeCo Insolvency Event — Exchange Right

Upon the occurrence and during the continuance of an Insolvency Event (as such term is defined in the Trust Agreement), the Share Trustee shall have the right (the “Exchange Right”) to require Parent or Callco to purchase from each Beneficiary all or any part of the Exchangeable Shares from each or any Beneficiary, provided that the Share Trustee may exercise such right only on the basis of instructions received from each such holder, and provided further that Parent may delegate its obligations thereunder to Callco. The purchase price payable by Parent or Callco, as the case may be, for each Exchangeable Share purchased pursuant to the exercise of the Exchange Right will be the Exchangeable Share Price on the last Business Day prior to the closing of the purchase and sale of such Exchangeable Share, which price will be satisfied in full by Parent or Callco delivering the Exchangeable Share Consideration representing such Exchangeable Share Price to the Share Trustee.

As soon as practicable following the occurrence of an Insolvency Event or any event that with the passage of time or the giving of notice or both would be an Insolvency Event, Parent and Holdco will give written notice thereof to the Share Trustee. As soon as practicable after receiving such notice, or upon the Share Trustee otherwise becoming aware of an Insolvency Event, the Share Trustee will give notice to each holder of Exchangeable Shares of such event and will advise the holder of its rights with respect to the Exchange Right.

Liquidation Event — Automatic Exchange Right

Immediately prior to the effective date of a Liquidation Event (as such term is defined in the Trust Agreement), each of the then outstanding Exchangeable Shares (other than Exchangeable Shares held by Parent and its affiliates) shall be automatically exchanged for one share of Delaware Common Stock, multiplied by the Exchangeable Share Exchange Ratio, rounded down to the nearest whole share in respect of each holder of Exchangeable Shares, together with a cash payment for any fractional interest equal to the fractional interest multiplied by the Current Market Price. Such automatic exchange shall be deemed to occur immediately prior to the Liquidation Event Effective Date.

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Comparative Per Share Data of Parent

Historical market price information regarding Parent is not provided because there is no public market for Parent capital stock.

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INFORMATION CONCERNING PARENT, EXCHANGECO AND CALLCO

General and Corporate Structure

Parent was formed on June 30, 2022 as a Delaware corporation. The principal office of Parent is located at 108 Patriot Drive, Suite A, Middletown, Delaware 19709. Parent intends to hold an annual meeting of stockholders following completion of the Redomicile Transactions.

Intercorporate Relationships

Assuming the Redomicile Resolution is approved at the Special Meeting, following the Effective Time and completion of the Redomicile Transactions, the stockholders of Parent will be the same persons who were Zymeworks Shareholders immediately prior to the Redomicile Transactions (other than those who have validly exercised Dissent Rights and holders of Exchangeable Shares prior to exchanging them for Delaware Common Stock) and Parent will become the direct or indirect owner of all of the assets and liabilities of Zymeworks. As a result, there will be no effective change of control of Zymeworks as a result of the Redomicile Transactions, as ultimate control will remain with the public stockholders. Upon completion of the Redomicile Transactions, Parent will have the general structure shown below.

Corporate Structure Prior to the Redomicile Transactions

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Corporate Structure Following the Redomicile Transactions

Common Stock

For a description of the shares of Delaware Common Stock see section titled “Description of Parent Capital Stock”.