Exhibit 1.1

16,500,000 Shares

CyrusOne Inc.

COMMON STOCK, PAR VALUE $0.01 PER SHARE

UNDERWRITING AGREEMENT

January 17, 2013

January 17, 2013

Morgan Stanley & Co. LLC

Merrill Lynch, Pierce, Fenner & Smith Incorporated

As Representatives of the several

Underwriters named in Schedule I hereto

c/o Morgan Stanley & Co. LLC

1585 Broadway

New York, New York 10036

Ladies and Gentlemen:

CyrusOne Inc., a Maryland corporation (the “ Company ”), CyrusOne GP, a Maryland statutory trust (the “ General Partner”), which is a subsidiary of the Company and the sole general partner of CyrusOne LP, a Maryland limited partnership (the “ Operating Partnership”), which is a subsidiary of the Company, each confirms its agreement with Morgan Stanley & Co. LLC (“ Morgan Stanley”) and Merrill Lynch, Pierce, Fenner & Smith Incorporated (“ Merrill Lynch”), as representatives (the “ Representatives ”) of the several underwriters named in Schedule I hereto (the “ Underwriters ”), with respect to the proposed issuance and sale of 16,500,000 shares of common stock, $0.01 par value per share, of the Company (the “ Firm Shares”) . The Company also proposes to issue and sell to the several Underwriters not more than an additional 2,475,000 shares of its common stock, par value $0.01 per share (the “ Additional Shares”), if and to the extent that you, as Representatives, shall have determined to exercise, on behalf of the Underwriters, the right to purchase such shares of common stock granted to the Underwriters in Section 2 hereof. The Firm Shares and the Additional Shares are hereinafter collectively referred to as the “ Shares .” The shares of common stock, par value $0.01 per share, of the Company to be outstanding after giving effect to the sales contemplated hereby are hereinafter referred to as the “ Common Stock. ”

Concurrently with or prior to the closing of the offering of the Shares, (i) the Operating Partnership received a contribution of direct and indirect interests in the portfolio of properties owned by Cincinnati Bell Inc. (“ CBI ”) and certain of its subsidiaries as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus, under the caption “Prospectus Summary—CyrusOne Inc.—Our Portfolio” in exchange for operating partnership units; and (ii) the Company and certain of the Subsidiaries (as defined below) will enter into transition services, registration rights and other commercial agreements with CBI and certain of its subsidiaries as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus, under the caption “Certain Relationships and Related Transactions” (the “ Transactions ,” and all agreements entered into in connection therewith, the “ Transaction Agreements”) .

The Company has filed with the Securities and Exchange Commission (the “ Commission ”) a registration statement, including a prospectus, relating to the Shares. The registration statement as amended at the time it becomes effective, including the information (if

any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430A under the Securities Act of 1933, as amended (the “ Securities Act”), is hereinafter referred to as the “ Registration Statement”; the prospectus in the form first used to confirm sales of Shares (or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “ Prospectus .” If the Company has filed an abbreviated registration statement to register additional shares of Common Stock pursuant to Rule 462(b) under the Securities Act (the “ Rule 462 Registration Statement”), then any reference herein to the term “ Registration Statement” shall be deemed to include such Rule 462 Registration Statement.

For purposes of this Agreement, “ free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act, “ Time of Sale Prospectus” means the preliminary prospectus together with the documents and pricing information set forth in Schedule II hereto, and “ broadly available road show” means a “bona fide electronic road show” as defined in Rule 433(h)(5) under the Securities Act that has been made available without restriction to any person. As used herein, the terms “Registration Statement,” “preliminary prospectus,” “Time of Sale Prospectus” and “Prospectus” shall include the documents, if any, incorporated by reference therein as of the date hereof.

Morgan Stanley has agreed to reserve a portion of the Shares to be purchased by it under this Agreement for sale to the Company’s directors, officers, employees and business associates and other parties related to the Company (collectively, the “ Participants ”), as set forth in the Prospectus under the heading “Underwriters” (the “ Directed Share Program”) . The Shares to be sold by Morgan Stanley and its affiliates pursuant to the Directed Share Program are referred to hereinafter as the “ Directed Shares”. Any Directed Shares not orally confirmed for purchase by any Participant by the end of the business day on which this Agreement is executed will be offered to the public by the Underwriters as set forth in the Prospectus.

1. Representations and Warranties. The Company, the General Partner and the Operating Partnership, jointly and severally, represent and warrant to and agree with each of the Underwriters that:

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“ Material Adverse Effect” means (A) a material adverse change in, or a material adverse effect upon, the operations, business, properties, prospects or condition (financial or otherwise) of the Company and its subsidiaries taken as a whole or (B) the material impairment of the ability of any of the Company or any of its subsidiaries to consummate the Transactions to which it is a party and to perform its material obligations under any of the documents related thereto.

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“ Applicable Law” means all laws, statutes, rules, regulations and orders of, and legally binding interpretations by, any Governmental Authority and judgments, decrees, injunctions, writs, permits, orders or like governmental action of any Governmental Authority applicable to the Company or any Subsidiary or any of their properties, assets or operations.

“ Governmental Authority” means any of (A) the government of the United States of America or any State or other political subdivision thereof, (B) any government or political subdivision of any other jurisdiction in which the Company or any Subsidiary conducts all or any part of its business, or which properly asserts jurisdiction over any properties of the Company or any Subsidiary, (C) any entity properly exercising executive, legislative, judicial, regulatory or administrative functions of any such government, (D) the NASDAQ Global Select Market (the “ NASDAQ ”) and (E) the Financial Industry Regulatory Authority, Inc. (“ FINRA ”).

“ Company Repayment Event” means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of the Subsidiaries.

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“ Environmental Laws” means all applicable foreign, federal, state or local laws, statutes, common law duties, rules, regulations, ordinances and codes, together with all administrative orders, Environmental Permits (as defined below) of, and legally-binding agreements with, any Governmental Authorities, in each case relating to environmental, health, safety and land use matters (including, without limitation the Comprehensive Environmental Response, Compensation and Liability Act of 1980, the Clean Air Act, the Federal Water Pollution Control Act of 1972, the Solid Waste Disposal Act and the Emergency Planning and Community Right-to-Know Act).

“ Environmental Permits” means all permits, licenses, registrations, consents, approvals and other authorizations of any Governmental Authority which are required with respect to any of the facilities of the Company or any of the Subsidiaries for operations under any applicable Environmental Laws.

“ Hazardous Materials” means (i) any petroleum or petroleum products, radioactive materials, asbestos in any form that is friable, urea formaldehyde foam insulation, polychlorinated biphenyls and radon gas; (ii) any chemicals, materials or substances defined as or included in the definition of “hazardous substances,” “hazardous waste,” “hazardous materials,” “extremely hazardous substances,” “restricted hazardous waste,” “toxic substances,” “toxic pollutants,” “contaminants,” or “pollutants,” or words of similar meaning and effect, under any applicable Environmental Law; and (iii) any other chemical, material or substance, the release of which is prohibited, limited or regulated by any Environmental Law.

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(ii) The Entity represents and covenants that it will not use the proceeds of the offering of the Shares, or lend, contribute or otherwise make available such proceeds to any Subsidiary, joint venture partner or other Person:

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2. Agreements to Sell and Purchase. The Company hereby agrees to sell to the several Underwriters, and each Underwriter, upon the basis of the representations and warranties herein contained, but subject to the conditions hereinafter stated, agrees, severally and not jointly, to purchase from the Company the respective numbers of Firm Shares set forth in Schedule I hereto opposite its name at $17.765 a share (the “ Purchase Price”) .

On the basis of the representations and warranties contained in this Agreement, and subject to its terms and conditions, the Company agrees to sell to the Underwriters the Additional Shares, and the Underwriters shall have the right to purchase, severally and not jointly, up to 2,475,000 Additional Shares at the Purchase Price, provided, however, that the amount paid by the Underwriters for any Additional Shares shall be reduced by an amount per share equal to any

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dividends declared by the Company and payable on the Firm Shares but not payable on such Additional Shares. You may exercise this right on behalf of the Underwriters in whole or from time to time in part by giving written notice not later than 30 days after the date of this Agreement. Any exercise notice shall specify the number of Additional Shares to be purchased by the Underwriters and the date on which such shares are to be purchased. Each purchase date must be at least one business day after the written notice is given and may not be earlier than the closing date for the Firm Shares nor later than ten business days after the date of such notice. Additional Shares may be purchased as provided in Section 4 hereof solely for the purpose of covering over-allotments made in connection with the offering of the Firm Shares. On each day, if any, that Additional Shares are to be purchased (an “ Option Closing Date”), each Underwriter agrees, severally and not jointly, to purchase the number of Additional Shares (subject to such adjustments to eliminate fractional shares as you may determine) that bears the same proportion to the total number of Additional Shares to be purchased on such Option Closing Date as the number of Firm Shares set forth in Schedule I hereto opposite the name of such Underwriter bears to the total number of Firm Shares.

3. Terms of Public Offering. The Company is advised by you that the Underwriters propose to make a public offering of their respective portions of the Shares as soon after the Registration Statement and this Agreement have become effective as in your judgment is advisable. The Company is further advised by you that the Shares are to be offered to the public initially at $19.00 a share (the “ Public Offering Price”) and to certain dealers selected by you at a price that represents a concession not in excess of $0.741 a share under the Public Offering Price.

4. Payment and Delivery. Payment for the Firm Shares shall be made to the Company in federal or other funds immediately available in New York City against delivery of such Firm Shares for the respective accounts of the several Underwriters at 10:00 a.m., New York City time, on January 24, 2013, or at such other time on the same or such other date, not later than January 31, 2013, as shall be designated in writing by you. The time and date of such payment are hereinafter referred to as the “ Closing Date. ”

Payment for any Additional Shares shall be made to the Company in federal or other funds immediately available in New York City against delivery of such Additional Shares for the respective accounts of the several Underwriters at 10:00 a.m., New York City time, on the date specified in the corresponding notice described in Section 2 hereof or at such other time on the same or on such other date, in any event not later than March 4, 2013, as shall be designated in writing by you.

The Firm Shares and Additional Shares shall be registered in such names and in such denominations as you shall request in writing not later than one full business day prior to the Closing Date or the applicable Option Closing Date, as the case may be. The Firm Shares and Additional Shares shall be delivered to you on the Closing Date or an Option Closing Date, as the case may be, for the respective accounts of the several Underwriters, with any transfer taxes payable in connection with the transfer of the Shares to the Underwriters duly paid, against payment of the Purchase Price therefor.

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5. Conditions to the Underwriters’ Obligations . The obligations of the Company to sell the Shares to the Underwriters and the several obligations of the Underwriters to purchase and pay for the Shares on the Closing Date are subject to the condition that the Registration Statement shall have become effective not later than 4:30 p.m. (New York City time) on the date hereof.

The several obligations of the Underwriters are subject to the following further conditions:

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The several obligations of the Underwriters to purchase Additional Shares hereunder are subject to the delivery to you on the applicable Option Closing Date of such documents as you may reasonably request with respect to the good standing of the Company, the General Partner and the Operating Partnership, the due authorization and issuance of the Additional Shares to be sold on such Option Closing Date and other matters related to the issuance of such Additional Shares.

6. Covenants of the Company. The Company covenants with each Underwriter as follows:

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The Company also covenants with each Underwriter that, except as disclosed in the Registration Statement, the Time of Sale Prospectus and the Prospectus under the caption “Certain Relationships and Related Transactions—Aggregate Consideration to CBI,” without the prior written consent of the Representatives on behalf of the Underwriters it will not, during the period ending 180 days after the date of the Prospectus, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right

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or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise or (iii) file any registration statement with the Commission relating to the offering of any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock.

The restrictions contained in the preceding paragraph shall not apply to (i) the Shares to be sold hereunder, (ii) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof of which the Underwriters have been advised in writing, (iii) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act, for the transfer of shares of Common Stock, provided that such plan does not provide for the transfer of Common Stock during the 180-day restricted period and no public announcement or filing under the Exchange Act regarding the establishment of such plan shall be required of or voluntarily made by or on behalf of the Company, (iv) the transfer of shares of the Company’s stock by operation of the provisions of Article VII of the Company’s charter, (v) the issuance of shares of Common Stock, the grant of rights to acquire shares of Common Stock, the reservation of shares of Common Stock for issuance, or the filing of a registration statement on Form S-8 relating to the offering of shares of Common Stock, in each case, pursuant to any of the Company’s stock incentive, compensation or similar employee benefit plans described in the Registration Statement and the Time of Sale Prospectus or (vi) the entry into an agreement providing for the issuance by the Company of shares of Common Stock (or any security convertible into or exercisable for shares of Common Stock) in connection with strategic investments (including joint ventures) or the acquisition by the Company or any of the Subsidiaries of the securities, business, property or other assets of another person or entity and the issuance of any such shares or securities pursuant to any such agreement; provided that the aggregate number of shares of Common Stock (or any securities convertible into or exercisable or exchangeable for Common Stock) that the Company may sell or issue or agree to sell or issue pursuant to clause (vi) shall not exceed 10% of the total number of shares of the Company’s Common Stock issued and outstanding immediately following the completion of the transactions contemplated by this Agreement; provided further that in the case of any issuance of shares of Common Stock (or any securities convertible into or exercisable or exchangeable for Common Stock) pursuant to clause (vi), any recipient of such shares or securities shall have executed and delivered to the Representatives a “lock-up” agreement substantially in the form of Exhibit E attached hereto and the Company shall enter stop transfer instructions with the Company’s transfer agent and registrar on such shares or securities, which the Company agrees it will not waive or amend without the prior written consent of the Representatives.

If Morgan Stanley and Merrill Lynch, in their sole discretion, agree to release or waive the restrictions set forth in a lock-up letter described in Section 5(i) hereof for an officer or director of the Company and provide the Company with notice of the impending release or waiver at least three business days before the effective date of the release or waiver, the Company agrees to announce the impending release or waiver by a press release substantially in the form of Exhibit F hereto through a major news service at least two business days before the effective date of the release or waiver.

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7. Covenants of the Underwriters. Each Underwriter severally covenants with the Company not to take any action that would result in the Company being required to file with the Commission under Rule 433(d) a free writing prospectus prepared by or on behalf of such Underwriter that otherwise would not be required to be filed by the Company thereunder, but for the action of the Underwriter.

8. Indemnity and Contribution. (a) Each of the Company, the General Partner and the Operating Partnership, jointly and severally, agrees to indemnify and hold harmless each Underwriter, each person, if any, who controls any Underwriter within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of any Underwriter within the meaning of Rule 405 under the Securities Act from and against any and all losses, claims, damages and liabilities (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim) caused by any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any amendment thereof, any preliminary prospectus, the Time of Sale Prospectus or any amendment or supplement thereto, any issuer free writing prospectus as defined in Rule 433(h) under the Securities Act, any Company information that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act, any road show as defined in Rule 433(h) under the Securities Act (a “road show”), or the Prospectus or any amendment or supplement thereto, or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, except insofar as such losses, claims, damages or liabilities are caused by any such untrue statement or omission or alleged untrue statement or omission based upon information relating to any Underwriter furnished to the Company in writing by such Underwriter through you expressly for use therein.

(b) Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, the General Partner, the Operating Partnership, their respective directors and officers, each person, if any, who controls the Company, the General Partner or the Operating Partnership within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of the Company, the General Partner and the Operating Partnership within the meaning of Rule 405 under the Securities Act to the same extent as the foregoing indemnity from the Company, the General Partner and the Operating Partnership to such Underwriter, but only with reference to information relating to such Underwriter furnished to the Company in writing by such Underwriter through you expressly for use in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any issuer free writing prospectus, road show, or the Prospectus or any amendment or supplement thereto.

(c) In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to Section 8(a) or 8(b) such person (the “ indemnified party ”) shall promptly notify the person against whom such

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indemnity may be sought (the “ indemnifying party ”) in writing and the indemnifying party, upon request of the indemnified party, shall retain counsel reasonably satisfactory to the indemnified party to represent the indemnified party and any others the indemnifying party may designate in such proceeding and shall pay the fees and disbursements of such counsel related to such proceeding. In any such proceeding, any indemnified party shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the retention of such counsel or (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood that the indemnifying party shall not, in respect of the legal expenses of any indemnified party in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the fees and expenses of more than one separate firm (in addition to any local counsel) for all such indemnified parties and that all such fees and expenses shall be reimbursed as they are incurred. Such firm shall be designated in writing by the Representatives, in the case of parties indemnified pursuant to Section 8(a), by the Company, the General Partner and the Operating Partnership, in the case of parties indemnified pursuant to Section 8(b). The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party from and against any loss or liability by reason of such settlement or judgment. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened proceeding in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party, unless such settlement includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such proceeding and does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

(d) To the extent the indemnification provided for in Section 8(a) or 8(b) is unavailable to an indemnified party or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each indemnifying party under such paragraph, in lieu of indemnifying such indemnified party thereunder, shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company, the General Partner and the Operating Partnership, on the one hand, and the Underwriters, on the other hand, from the offering of the Shares or (ii) if the allocation provided by clause 8(d)(i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause 8(d)(i) above but also the relative fault of the Company, the General Partner and the Operating Partnership, on the one hand, and of the Underwriters, on the other hand, in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company, the General Partner and the Operating Partnership, on the one hand, and the Underwriters, on the other hand, in connection with the offering of the Shares shall be deemed to be in the same respective proportions as the net proceeds from the offering of the Shares (before

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deducting expenses) received by the Company, the General Partner and the Operating Partnership and the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate Public Offering Price of the Shares. The relative fault of the Company, the General Partner and the Operating Partnership, on the one hand, and the Underwriters, on the other hand, shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company, the General Partner and the Operating Partnership or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Underwriters’ respective obligations to contribute pursuant to this Section 8 are several in proportion to the respective number of Shares they have purchased hereunder, and not joint.

(e) The Company, the General Partner, the Operating Partnership and the Underwriters agree that it would not be just or equitable if contribution pursuant to this Section 8 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in Section 8(d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages and liabilities referred to in Section 8(d) shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 8, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The remedies provided for in this Section 8 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any indemnified party at law or in equity.

(f) The indemnity and contribution provisions contained in this Section 8 and the representations, warranties and other statements of the Company, the General Partner and the Operating Partnership contained in this Agreement shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of any Underwriter, any person controlling any Underwriter or any affiliate of any Underwriter or by or on behalf of the Company, its officers or directors, the General Partner, the Operating Partnership or any person controlling the Company, the General Partner and the Operating Partnership and (iii) acceptance of and payment for any of the Shares.

9. Directed Share Program Indemnification. (a) Each of the Company, the General Partner and the Operating Partnership, jointly and severally, agrees to indemnify and hold harmless Morgan Stanley, each person, if any, who controls Morgan Stanley within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of Morgan Stanley within the meaning of Rule 405 under the Securities Act (“ Morgan Stanley Entities ”)

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from and against any and all losses, claims, damages and liabilities (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim) (i) caused by any untrue statement or alleged untrue statement of a material fact contained in any material prepared by or with the consent of the Company, the General Partner or the Operating Partnership for distribution to Participants in connection with the Directed Share Program or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, when considered in conjunction with the Prospectus, the Time of Sale Prospectus or any applicable preliminary prospectus, not misleading; (ii) caused by the failure of any Participant to pay for and accept delivery of Directed Shares that the Participant had properly confirmed in its agreement to purchase; or (iii) related to, arising out of, or in connection with the Directed Share Program, other than losses, claims, damages or liabilities (or expenses relating thereto) that are finally judicially determined to have resulted from the bad faith or gross negligence of Morgan Stanley Entities.

(b) In case any proceeding (including any governmental investigation) shall be instituted involving any Morgan Stanley Entity in respect of which indemnity may be sought pursuant to Section 9, the Morgan Stanley Entity seeking indemnity, shall promptly notify the Company, the General Partner and the Operating Partnership in writing and the Company, the General Partner and the Operating Partnership, upon request of the Morgan Stanley Entity, shall retain counsel reasonably satisfactory to the Morgan Stanley Entity to represent the Morgan Stanley Entity and any others the Company, the General Partner and the Operating Partnership may designate in such proceeding and shall pay the fees and disbursements of such counsel related to such proceeding. In any such proceeding, any Morgan Stanley Entity shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such Morgan Stanley Entity unless (i) the Company, the General Partner and the Operating Partnership shall have agreed to the retention of such counsel or (ii) the named parties to any such proceeding (including any impleaded parties) include both the Company, the General Partner or the Operating Partnership and the Morgan Stanley Entity and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. The Company, the General Partner and the Operating Partnership shall not, in respect of the legal expenses of the Morgan Stanley Entities in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the fees and expenses of more than one separate firm (in addition to any local counsel) for all Morgan Stanley Entities. Any such separate firm for the Morgan Stanley Entities shall be designated in writing by Morgan Stanley. The Company, the General Partner and the Operating Partnership shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, each of the Company, the General Partner and the Operating Partnership, jointly and severally, agrees to indemnify the Morgan Stanley Entities from and against any loss or liability by reason of such settlement or judgment. The Company, the General Partner and the Operating Partnership shall not, without the prior written consent of Morgan Stanley, effect any settlement of any pending or threatened proceeding in respect of which any Morgan Stanley Entity is or could have been a party and indemnity could have been sought hereunder by such Morgan Stanley Entity, unless such settlement includes an unconditional release of the Morgan Stanley Entities from all liability on claims that are the subject matter of such proceeding.

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To the extent the indemnification provided for in Section 9 is unavailable to a Morgan Stanley Entity or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then the Company, the General Partner and the Operating Partnership in lieu of indemnifying the Morgan Stanley Entity thereunder, shall contribute to the amount paid or payable by the Morgan Stanley Entity as a result of such losses, claims, damages or liabilities (c) in such proportion as is appropriate to reflect the relative benefits received by the Company, the General Partner and the Operating Partnership, on the one hand, and the Morgan Stanley Entities, on the other hand, from the offering of the Directed Shares or (d) if the allocation provided by clause 9(c) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause 9(c) above but also the relative fault of the Company, the General Partner and the Operating Partnership, on the one hand, and of the Morgan Stanley Entities, on the other hand, in connection with any statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company, the General Partner and the Operating Partnership, on the one hand, and the Morgan Stanley Entities, on the other hand, in connection with the offering of the Directed Shares shall be deemed to be in the same respective proportions as the net proceeds from the offering of the Directed Shares (before deducting expenses) and the total underwriting discounts and commissions received by the Morgan Stanley Entities for the Directed Shares, bear to the aggregate Public Offering Price of the Directed Shares. If the loss, claim, damage or liability is caused by an untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact, the relative fault of the Company, the General Partner and the Operating Partnership, on the one hand, and the Morgan Stanley Entities, on the other hand, shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company, the General Partner and the Operating Partnership or by the Morgan Stanley Entities and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(e) The Company, the General Partner, the Operating Partnership and the Morgan Stanley Entities agree that it would not be just or equitable if contribution pursuant to this Section 9 were determined by pro rata allocation (even if the Morgan Stanley Entities were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in Section 9(c). The amount paid or payable by the Morgan Stanley Entities as a result of the losses, claims, damages and liabilities referred to in the immediately preceding paragraph shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by the Morgan Stanley Entities in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 9, no Morgan Stanley Entity shall be required to contribute any amount in excess of the amount by which the total price at which the Directed Shares distributed to the public were offered to the public exceeds the amount of any damages that such Morgan Stanley Entity has otherwise been required to pay. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from

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any person who was not guilty of such fraudulent misrepresentation. The remedies provided for in this Section 9 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any Morgan Stanley Entity at law or in equity.

(f) The indemnity and contribution provisions contained in this Section 9 shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of any Morgan Stanley Entity or the Company, the General Partner or the Operating Partnership, its officers or directors or any person controlling the Company, the General Partner or the Operating Partnership and (iii) acceptance of and payment for any of the Directed Shares.

10. Termination. The Underwriters may terminate this Agreement by notice given by you to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date (i) trading generally shall have been suspended or materially limited on, or by, as the case may be, the New York Stock Exchange or the NASDAQ Global Select Market, (ii) trading of any securities of the Company shall have been suspended on any exchange or in any over-the-counter market, (iii) a material disruption in securities settlement, payment or clearance services in the United States shall have occurred, (iv) any moratorium on commercial banking activities shall have been declared by federal or New York State authorities or (v) there shall have occurred any outbreak or escalation of hostilities, or any change in financial markets or any calamity or crisis that, in your judgment, is material and adverse and which, singly or together with any other event specified in this clause (v), makes it, in your judgment, impracticable or inadvisable to proceed with the offer, sale or delivery of the Shares on the terms and in the manner contemplated in the Registration Statement, the Time of Sale Prospectus or the Prospectus.

11. Effectiveness; Defaulting Underwriters. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

If, on the Closing Date or an Option Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Shares that it has or they have agreed to purchase hereunder on such date, and the aggregate number of Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase is not more than one-tenth of the aggregate number of the Shares to be purchased on such date, the other Underwriters shall be obligated severally in the proportions that the number of Firm Shares set forth opposite their respective names in Schedule I hereto bears to the aggregate number of Firm Shares set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as you may specify, to purchase the Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date; provided that in no event shall the number of Shares that any Underwriter has agreed to purchase pursuant to this Agreement be increased pursuant to this Section 11 by an amount in excess of one-ninth of such number of Shares without the written consent of such Underwriter. If, on the Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase Firm Shares and the aggregate number of Firm Shares with respect to which such default occurs is more than one-tenth of the aggregate number of Firm Shares to be purchased on such date, and arrangements satisfactory to you and the Company for the purchase of such Firm Shares are not made within 36 hours after such default,

33

this Agreement shall terminate without liability on the part of any non-defaulting Underwriter, the Company, the General Partner or the Operating Partnership. In any such case either you or the Company shall have the right to postpone the Closing Date, but in no event for longer than seven days, in order that the required changes, if any, in the Registration Statement, in the Time of Sale Prospectus, in the Prospectus or in any other documents or arrangements may be effected. If, on an Option Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase Additional Shares and the aggregate number of Additional Shares with respect to which such default occurs is more than one-tenth of the aggregate number of Additional Shares to be purchased on such Option Closing Date, the non-defaulting Underwriters shall have the option to (i) terminate their obligation hereunder to purchase the Additional Shares to be sold on such Option Closing Date or (ii) purchase not less than the number of Additional Shares that such non-defaulting Underwriters would have been obligated to purchase in the absence of such default. Any action taken under this paragraph shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

If this Agreement shall be terminated by the Underwriters, or any of them, because of any failure or refusal on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement, or if for any reason the Company shall be unable to perform its obligations under this Agreement, the Company will reimburse the Underwriters or such Underwriters as have so terminated this Agreement with respect to themselves, severally, for all out-of-pocket expenses (including the fees and disbursements of their counsel) reasonably incurred by such Underwriters in connection with this Agreement or the offering contemplated hereunder.

12. Research Analyst Independence. Each of the Company, the General Partner and the Operating Partnership acknowledges that the Underwriters’ research analysts and research departments are required to be independent from their respective investment banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering that differ from the views of their respective investment banking divisions. Each of the Company, the General Partner and the Operating Partnership acknowledges that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws, may effect transactions for its own account or the account of its customers and hold long or short positions in debt or equity securities of the companies that may be the subject of the transactions contemplated by this Agreement.

13. Entire Agreement. (a) This Agreement, together with any contemporaneous written agreements and any prior written agreements (to the extent not superseded by this Agreement) that relate to the offering of the Shares, represents the entire agreement between the Company, the General Partner, the Operating Partnership and the Underwriters with respect to the preparation of any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, the conduct of the offering, and the purchase and sale of the Shares.

34

(b) Each of the Company, the General Partner and the Operating Partnership acknowledges that in connection with the offering of the Shares: (i) the Underwriters have acted at arms length, are not agents of, and owe no fiduciary duties to, the Company, the General Partner and the Operating Partnership or any other person, (ii) the Underwriters owe the Company, the General Partner and the Operating Partnership only those duties and obligations set forth in this Agreement and prior written agreements (to the extent not superseded by this Agreement), if any, and (iii) the Underwriters may have interests that differ from those of the Company, the General Partner and the Operating Partnership. Each of the Company, the General Partner and the Operating Partnership waives to the full extent permitted by applicable law any claims it may have against the Underwriters arising from an alleged breach of fiduciary duty in connection with the offering of the Shares.

14. Counterparts. This Agreement may be signed in two or more counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument.

15. Applicable Law. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York without giving effect to any choice of law or conflicting provision or rule (whether of the State of New York, or of any other jurisdiction) that would cause the laws of any jurisdiction other than the State of New York to be applied.

16. Headings. The headings of the sections of this Agreement have been inserted for convenience of reference only and shall not be deemed a part of this Agreement.

17. Trial by Jury. Each of the Company (on its behalf and, to the extent permitted by applicable law, on behalf of its stockholders and affiliates), the General Partner (on its behalf and, to the extent permitted by applicable law, on behalf of its sole trustee and affiliates) and the Operating Partnership (on its behalf and, to the extent permitted by applicable law, on behalf of its limited partners and affiliates) and each of the Underwriters hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

18. Notices. All communications hereunder shall be in writing and effective only upon receipt and if to the Underwriters shall be delivered, mailed or sent to Morgan Stanley & Co. LLC, 1585 Broadway, New York, New York 10036, Attention: Equity Syndicate Desk, with a copy to the Legal Department, and Merrill Lynch, Pierce, Fenner & Smith Incorporated, One Bryant Park, New York, New York 10036, Attention: Syndicate Department (facsimile: (646) 855-3073), with a copy to ECM Legal (facsimile: (212) 230-8730); if to the Company, the General Partner or the Operating Partnership shall be delivered, mailed or sent to CyrusOne Inc., 1649 West Frankford Road, Carrollton, Texas 75007, Attention: Kim Sheehy, with a copy to Cravath, Swaine & Moore LLP, Worldwide Plaza, 825 Eighth Avenue, New York, New York, 10019, Attention: William V. Fogg, Esq.

(Remainder of Page Intentionally Left Blank)

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[ Signature Page to Underwriting Agreement ]

[ Signature Page to Underwriting Agreement ]

I-1

SCHEDULE II

Time of Sale Prospectus

II-1

SCHEDULE III

SIGNIFICANT SUBSIDIARIES

CyrusOne LLC

CyrusOne TRS Inc.

CyrusOne Foreign Holdings LLC

III-1

EXHIBIT A

MATTERS TO BE COVERED BY CRAVATH, SWAINE AND MOORE LLP OPINION AND 10B-5 LETTER

1. Based solely on certificates from the Secretary of State of the State of Delaware, each of CyrusOne TRS Inc., CyrusOne LLC and Cyrus One Foreign Holdings LLC (the “ Delaware Subsidiaries ”) is a corporation or limited liability company validly existing and in good standing under the laws of the State of Delaware, with all necessary corporate or limited liability company power and authority to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Specified Disclosure Package and the Prospectus.

2. No authorization, approval or other action by, and no notice to, consent of, order of, or filing with, any United States federal, New York State or, to the extent applicable under the General Corporation Law of the State of Delaware, Delaware governmental authority is required to be made or obtained by the Company, the General Partner or the Operating Partnership for the execution and delivery of the Underwriting Agreement, the consummation of the transactions contemplated by the Underwriting Agreement and the performance by the Company, the General Partner and the Operating Partnership of their respective obligations under the Underwriting Agreement, other than (i) those that have been obtained or made, (ii) those that may be required under the Securities Act in connection with the use of a “free writing prospectus,” (iii) those that may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Shares by the Underwriters or (iv) those as to which the failure to be obtained or made would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect (as defined in the Underwriting Agreement).

3. The execution and delivery of the Underwriting Agreement, the consummation of the transactions contemplated by the Underwriting Agreement and the performance by the Company, the General Partner and the Operating Partnership of their respective obligations under the Underwriting Agreement (i) do not result in a breach of or constitute a default under the express terms and conditions of any agreement listed on Schedule A-1 attached hereto (each, a “ Specified Agreement ”) and (ii) do not violate any law, rule or regulation of the United States of America, the State of New York or the General Corporation Law of the State of Delaware applicable to the Company, the General Partner or the Operating Partnership, except, in the case of clause (ii), such violations that, individually or in the aggregate, would not have a Material Adverse Effect. Such counsel’s opinion in clause (i) of the preceding sentence relating to the Specified Agreements does not extend to compliance with any financial ratio or any limitation in any contractual restriction expressed as a dollar amount (or an amount expressed in another currency). Such counsel note that certain of the Specified Agreements are governed by laws other than New York law; such counsel’s opinions expressed herein are based solely upon such counsel’s understanding of the plain language of such agreements, and such counsel does not express any opinion with respect to the validity, binding nature or enforceability of any such agreement, and such counsel does not assume any responsibility with respect to the effect on the opinions or statements set forth herein of any interpretation thereof inconsistent with such understanding.

A-1

4. Assuming that the Registration Rights Agreement has been duly authorized, executed and delivered by each of the parties thereto, the Registration Rights Agreement constitutes a valid and binding obligation of each of the Company, the General Partner and the Operating Partnership, enforceable against each of the Company, the General Partner and the Operating Partnership in accordance with its terms (subject to applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer and other similar laws affecting creditors’ rights generally from time to time in effect and to general principles of equity, including, without limitation, concepts of materiality, reasonableness, good faith and fair dealing, regardless of whether considered in a proceeding in equity or at law).

5. The statements made in the Registration Statement, the Time of Sale Prospectus and the Prospectus under the captions “Certain Relationships and Related Transactions—Contribution Agreements,” “Shares Eligible for Future Sale,” “ERISA Considerations” and “Underwriting,” in each case insofar as they purport to describe provisions of documents and United States federal laws referred to therein, constitute accurate summaries of the matters described therein in all material respects.

6. Based solely on the certificate dated the date hereof, from an officer of the Company, attached as Annex A hereto, the Company is not required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

7. The Registration Statement became effective under the Securities Act on [ · ], 2013, and thereupon the offering of the Shares as contemplated by the Prospectus became registered under the Securities Act; to such counsel’s knowledge, no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or are pending or contemplated under the Securities Act.

8. The Shares have been duly authorized for listing, subject to official notice of issuance, on the NASDAQ Global Select Market.

In addition to furnishing the opinions set forth above, such counsel shall also deliver a letter stating that, subject to certain limitations and qualifications and on the basis of information gained in the course of the performance of the services rendered, the Registration Statement, at the time it initially became effective, and the Prospectus, as of the date of such letter, appeared or appears on its face to be appropriately responsive in all material respects to the requirements of the Securities Act and the applicable rules and regulations thereunder, except that such counsel does not express any view as to the financial statements and other information of a statistical, accounting or financial nature included therein. Furthermore, such counsel shall also advise you that such counsel’s work in connection with this matter did not disclose any information that gave such counsel reason to believe that: (i) the Registration Statement, at the time the Registration Statement became effective, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements

A-2

therein not misleading, (ii) the Prospectus, as of its date or at the date hereof, included or includes, an untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading or (iii) the [Specified Disclosure Package], considered together as of [ · ] [am][pm] (New York Time) on [ · ], 2013 (the “ Applicable Time ”), included an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that, in each case, such counsel does not express any view as to the financial statements and other information of a statistical, accounting or financial nature included therein.

A-3

EXHIBIT B

MATTERS TO BE COVERED BY VENABLE LLP OPINION

1. The Company is a corporation duly incorporated and validly existing under the laws of the State of Maryland and is in good standing with the SDAT, and the Company has all necessary corporate power to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus and to enter into and perform its obligations under the Underwriting Agreement, the Partnership Agreement and the Transaction Documents to which it is a party.

2. CyrusOne Finance is a corporation duly incorporated and validly existing under the laws of the State of Maryland and is in good standing with the SDAT.

3. The General Partner is a statutory trust duly formed and validly existing under the laws of the State of Maryland and is in good standing with the SDAT, and the General Partner has all necessary trust power to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus and to enter into and perform its obligations under the Underwriting Agreement, the Partnership Agreement and the Transaction Documents to which it is a party.

4. The Operating Partnership is a limited partnership duly formed and validly existing under the laws of the State of Maryland and is in good standing with the SDAT, and the Operating Partnership has all necessary limited partnership power to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus and to enter into and perform its obligations under the Underwriting Agreement and the Transaction Documents to which it is party.

5. The number of shares of authorized stock of the Company is as set forth under the caption “Description of Securities—General” in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus. The issuance of the Outstanding Shares has been duly authorized by all necessary corporate action on the part of the Company, and the Outstanding Shares are validly issued, fully paid and nonassessable, and none of the Outstanding Shares were issued in violation of any preemptive or other similar rights of any security holder of the Company arising under the Maryland General Corporation Law (the “MGCL”) or the Charter or the Bylaws.

6. The issuance of the Incentive Plan Shares pursuant to the Incentive Plan and any award agreements entered into in connection with the grant thereof has been duly authorized by all necessary corporate action on the part of the Company, and, when and if issued and delivered in accordance with the terms of the Incentive Plan and any such award agreements, the Incentive Plan Shares will be validly issued, fully paid and nonassessable, and none of the Incentive Plan Shares will be issued in violation of any preemptive or other similar rights of any security holder of the Company arising under the MGCL or the Charter or the Bylaws.

B-1

7. Based solely on the Officer’s Certificate and any facts otherwise known to us, the Company has not issued any outstanding securities convertible into or exchangeable for, or outstanding options, warrants or other rights to purchase or subscribe for, any shares of stock or other securities of the Company, except as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus and except for the Incentive Plan Shares to be issued on or about the date hereof. No holder of shares of Common Stock has any preemptive or other similar rights arising under the MGCL or the Charter or the Bylaws.

8. The issuance of the Shares pursuant to the Underwriting Agreement has been duly authorized by all necessary corporate action on the part of the Company, and, when and if issued and delivered against payment therefor in accordance with the terms of the Underwriting Agreement, the Shares will be validly issued, fully paid and nonassessable, and no holder of the Shares is or will be subject to personal liability solely by reason of being such a holder.

9. The Form Certificate complies in all material respects with the requirements of the MGCL and the Charter and the Bylaws. The Shares conform as to legal matters in all material respects to the description thereof set forth in the Registration Statement, the Time of Sale Prospectus and the Prospectus under the caption “Description of Securities.”

10. The issuance of the Shares pursuant to the Underwriting Agreement is not subject to any preemptive or other similar rights of any security holder of the Company arising under the MGCL or the Charter or the Bylaws.

11. The issuance of the Company Units to the Company in exchange for the contribution by the Company to the Operating Partnership of certain proceeds of the issuance and sale of the Shares pursuant to the Partnership Agreement has been duly authorized by all necessary limited partnership action on the part of the Operating Partnership, and, when and if issued and delivered in exchange for such contribution and otherwise in accordance with the terms of the Partnership Agreement and the Resolutions, the Company Units will be validly issued pursuant to the Partnership Agreement.

12. The issuance of the CBI Units pursuant to the Contribution Agreements and the Prior Partnership Agreement has been duly authorized by all necessary limited partnership action on the part of the Operating Partnership, and the CBI Units are validly issued pursuant to the Partnership Agreement.

13. The issuance of the OP Unit Shares in exchange for the Exchanged Units in accordance with the terms of the Partnership Agreement and the Stock Subscription Agreement has been duly authorized by all necessary corporate action on the part of the Company, and, when and if issued and delivered upon the exchange of the Exchanged Units in accordance with the terms of the Partnership Agreement and the Stock Subscription Agreement, the OP Unit Shares will be validly issued, fully paid and nonassessable, and none of the OP Unit Shares will be issued in violation of any preemptive or other similar rights of any security holder of the Company arising under the MGCL or the Charter or the Bylaws, and no holder of the OP Unit Shares is or will be subject to personal liability solely by reason of being such a holder.

B-2

14. The issuance of the Offering Expense Shares in accordance with the terms of the Stock Subscription Agreement has been duly authorized by all necessary corporate action on the part of the Company, and, when and if issued and delivered against payment therefor in accordance with the terms of the Stock Subscription Agreement, the Offering Expense Shares will be validly issued, fully paid and nonassessable, and none of the Offering Expense Shares will be issued in violation of any preemptive or other similar rights of any security holder of the Company arising under the MGCL or the Charter or the Bylaws, and no holder of the Offering Expense Shares is or will be subject to personal liability solely by reason of being such a holder.

15. The execution and delivery by each of the Company, the General Partner and the Operating Partnership of, and the performance by each of the Company, the General Partner and the Operating Partnership of its respective obligations under, the Underwriting Agreement and the Transaction Documents to which it is a party have been duly authorized by all necessary corporate, trust and limited partnership action on the part of the Company, the General Partner and the Operating Partnership, respectively, and each of the Company, the General Partner and the Operating Partnership has duly executed and delivered the Underwriting Agreement and the Transaction Documents to which it is a party.

16. The execution and delivery by the Company of the Underwriting Agreement, the Partnership Agreement and the Transaction Documents to which it is party, the issuance and sale of the Shares by the Company to the Underwriters pursuant to the Underwriting Agreement and the consummation by the Company of the transactions contemplated by the Transaction Documents (including the exchange of the Exchange Units and the issuance of the OP Unit Shares and Offering Expense Shares), do not on the date hereof: (a) conflict with the provisions of the Charter or the Bylaws; (b) other than the securities statutes, rules and regulations of the State of Maryland, as to which we express no opinion, violate any Maryland statute, rule or regulation applicable to the Company; or (c) require any consents, approvals or authorizations to be obtained by the Company from, or any registrations, declarations or filings to be made by the Company with, any governmental authority under any Maryland statute, rule or regulation applicable to the Company that have not been obtained or made, except as may be required in connection with the securities statutes, rules or regulations of the State of Maryland, as to which we express no opinion.

17. The execution and delivery by the General Partner of the Underwriting Agreement, the Partnership Agreement and the Transaction Documents to which it is party, the issuance and sale of the Shares by the Company to the Underwriters pursuant to the Underwriting Agreement and the consummation by the General Partner of the transactions contemplated by the Transaction Documents (including the exchange of the Exchange Units and the issuance of the OP Unit Shares and Offering Expense Shares), do not on the date hereof: (a) conflict with the provisions of the Declaration of Trust; (b) other than the securities statutes, rules and regulations of the State of Maryland, as to which we express no opinion, violate any Maryland statute, rule or regulation applicable to the General Partner; or (c) require any consents, approvals or authorizations to be obtained by the General Partner from, or any registrations, declarations or filings to be made by the General Partner with, any governmental authority under any Maryland statute, rule or regulation applicable to the General Partner that have not been obtained or made, except as may be required in connection with the securities statutes, rules or regulations of the State of Maryland, as to which we express no opinion.

B-3

18. The execution and delivery by the Operating Partnership of the Underwriting Agreement and the Transaction Documents to which it is party, the issuance and sale of the Shares by the Company to the Underwriters pursuant to the Underwriting Agreement and the consummation by the Operating Partnership of the transactions contemplated by the Transaction Documents (including the exchange of the Exchange Units and the issuance of the OP Unit Shares and Offering Expense Shares), do not on the date hereof: (a) violate the provisions of the Partnership Agreement; (b) other than the securities statutes, rules and regulations of the State of Maryland, as to which we express no opinion, violate any Maryland statute, rule or regulation applicable to the Operating Partnership; or (c) require any consents, approvals or authorizations to be obtained by the Operating Partnership from, or any registrations, declarations or filings to be made by the Operating Partnership with, any governmental authority under any Maryland statute, rule or regulation applicable to the Operating Partnership that have not been obtained or made, except as may be required in connection with the securities statutes, rules or regulations of the State of Maryland, as to which we express no opinion.

19. The execution and delivery by each of the Company and the General Partner of, and the performance by each of the Company and the General Partner of its respective obligations under, the Partnership Agreement have been duly authorized by all necessary corporate and trust action on the part of the Company and the General Partner, respectively, and each of the Company and the General Partner has duly executed and delivered the Partnership Agreement, and the Partnership Agreement constitutes a valid and binding agreement of the Company and the General Partner, enforceable against the Company and the General Partner in accordance with its terms.

20. The information in the Registration Statement, the Time of Sale Prospectus and the Prospectus under the captions “Risk Factors—Risks Related to Our Organizational Structure,” “Management—Indemnification and Limitation of Directors’ and Officers’ Liability,” “Description of Securities,” “Description of the Partnership Agreement of CyrusOne LP” and “Certain Provisions of Maryland Law and of Our Charter and Bylaws,” and in Part II of the Registration Statement under the caption “Item 34. Indemnification of Directors and Officers,” in each case insofar as it constitutes summaries of Maryland law, the Charter, the Bylaws or the Partnership Agreement, or legal conclusions related thereto, has been reviewed by us and is correct in all material respects.

B-4

EXHIBIT C

MATTERS TO BE ADDRESSED IN TAX OPINION OF

SKADDEN, ARPS, SLATE, MEAGHER & FLOM

1. Commencing with its taxable year ending on December 31, 2013, CyrusOne has been organized in conformity with the requirements for qualification and taxation as a real estate investment trust (“REIT”) under the Code, and its proposed method of operation will enable it to meet the requirements for qualification and taxation as a REIT under the Code.

2. Although the discussion set forth in the Registration Statement under the heading “U.S. Federal Income Tax Considerations” does not purport to discuss all possible United States Federal income tax consequences of the ownership and disposition of shares of Common Stock, such discussion, though general in nature, constitutes, in all material respects, a fair and accurate summary under current law of the material United States Federal income tax consequences of the ownership and disposition of shares of Common Stock, subject to the qualifications set forth therein. The United States Federal income tax consequences of the ownership and disposition of shares of Common Stock by a holder will depend upon that holder’s particular situation, and we express no opinion as to the completeness of the discussion set forth in “U.S. Federal Income Tax Considerations” as applied to any particular holder.

C-1

EXHIBIT D

MATTERS TO BE COVERED BY THE LAW OFFICES OF THOMAS W. BOSSE PLLC

1. Based solely on the SOS Certificates filed in the applicable states, the Company is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-1 attached hereto.

2. Based solely on the SOS Certificates filed in the applicable states, Operating Partnership is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-2 attached hereto.

3. Based solely on the SOS Certificates filed in the applicable states, the General Partner is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-3 attached hereto.

4. Based solely on the SOS Certificates filed in the applicable states, CyrusOne TRS Inc. is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-4 attached hereto.

5. Based solely on the SOS Certificates filed in the applicable states, CyrusOne LLC is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-5 attached hereto.

6. Based solely on the SOS Certificates filed in the applicable states, CyrusOne Foreign Holdings LLC is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-6 attached hereto.

7. Based solely on the SOS Certificates filed in the applicable states, CyrusOne Finance Corp. is qualified to do business as a foreign entity in those states set forth opposite its name in Exhibit A-7 attached hereto.

8. The statements made in the Registration Statement, the Time of Sale Prospectus and Prospectus under the caption “Certain Relationships and Related Transactions,” aside from those set forth under the subheading “—Contribution Agreements,” insofar as they purport to constitute summaries of the terms of the documents described therein, accurately summarize the matters therein described in all material respects.

9. To our knowledge, there are no legal or governmental proceedings pending to which the Company or its Subsidiaries is a party or of which any property or assets of the Company or its Subsidiaries is the subject that could, in the aggregate, reasonably be expected to have a Material Adverse Effect (as defined in the Underwriting Agreement); and to our knowledge, no such proceedings are threatened or contemplated by governmental authorities or others.

D-1

10. To our knowledge, neither the Company nor any of its Subsidiaries is a party to any agreement that would require the inclusion in the Registration Statement of any securities of the Company owned by any person or entity other than the Company.

D-2

Exhibit 1.2

EXECUTION COPY

REGISTRATION RIGHTS AGREEMENT

THIS REGISTRATION RIGHTS AGREEMENT, dated as of January 24, 2013, is entered into by and among CyrusOne Inc., a Maryland corporation (the “ Company ”), CyrusOne GP, a Maryland statutory trust (the “ General Partner ”), CyrusOne LP, a Maryland limited partnership (the “ Operating Partnership ”), Data Center Investments Holdco LLC, a Delaware limited liability company (“ DCI Holdco ”), and Data Centers South Holdings LLC, a Delaware limited liability company (together with DCI Holdco, the “ Unit Holders ” and, each individually, a “ Unit Holder ”).

RECITALS

WHEREAS, in connection with the initial public offering of shares of the Company’s common stock, par value $0.01 per share (the “ Common Stock ”), the Company, the General Partner and the Operating Partnership have engaged in certain formation transactions (the “ Formation Transactions ”) whereby the Unit Holders (or certain related parties) received, in exchange for their (or certain related parties’) direct or indirect ownership interests (the “ Interests ”) in certain properties (the “ Properties ”), units of limited partnership interests (“ OP Units ”) in the Operating Partnership and were admitted as limited partners of the Operating Partnership;

WHEREAS, in connection with the consummation of the Initial Public Offering (as defined below), the Company shall issue to DCI Holdco shares of Common Stock with an aggregate value of $7,111,302, which number of shares of Common Stock shall be determined based on the public offering price of shares of Common Stock in the Initial Public Offering, in consideration of the full satisfaction of the intercompany debt incurred by the Company in connection with certain expenses related to the Initial Public Offering that have been incurred by DCI Holdco on behalf of the Company (the “ Intercompany Debt Issuance ”);

WHEREAS, simultaneously with the consummation of the Initial Public Offering and the effectiveness of the Partnership Agreement (as defined below), the Company shall issue additional shares of Common Stock to Holdco in exchange for the redemption of OP Units held by DCI Holdco which, together with the shares of Common Stock issued to DCI Holdco in the Intercompany Debt Issuance, will equal 9.74 percent of the outstanding shares of Common Stock (the “ Stock Redemption ”) and, together with the Intercompany Debt Issuance, the “ IPO Stock Issuance ”);

WHEREAS, pursuant to the Partnership Agreement, OP Units will be redeemable for cash or, at the Company’s option, exchangeable for shares of Common Stock upon the terms and subject to the conditions contained therein; and

WHEREAS, as a condition to receiving the consent of the Unit Holders to the Formation Transactions and in connection with the IPO Stock Issuance, the Company has agreed to grant to the Unit Holders and their permitted assignees and transferees the registration rights set forth in Article II hereof.

NOW, THEREFORE, in consideration of the premises and the mutual agreements herein contained, and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

ARTICLE I

DEFINITIONS

SECTION 1.1. Definitions . In addition to the definitions set forth above, the following terms, as used herein, have the following meanings:

“ Affiliate ” of any Person means any other Person directly or indirectly controlling or controlled by or under common control with such Person. For the purposes of this definition, “control” when used with respect to any Person, means the possession, directly or indirectly, of the power to direct or cause the direction of the management and policies of such Person, whether through the ownership of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative to the foregoing.

“ Agreemen t” means this Registration Rights Agreement, as it may be amended, supplemented or restated from time to time.

“ Articles of Amendment ” means the Articles of Amendment and Restatement of the Company as filed with the State Department of Assessments and Taxation of Maryland on January 17, 2013, as the same may be amended, modified or restated from time to time.

“ Business Day ” means any day except a Saturday, Sunday or other day on which commercial banks in The City of New York are authorized by law to close.

“ Commission ” means the Securities and Exchange Commission.

“ Demand Registration ” means a Demand Registration as defined in Section 2.2.

“ End of Suspension Notice ” means an End of Suspension Notice as defined in Section 2.5.

“ Exchange Act ” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

“ Exchangeable OP Units ” means OP Units which may be redeemable for cash or, at the Company’s option, exchangeable for shares of Common Stock pursuant to Section 15.1 of the Partnership Agreement (without regard to any limitations on the exercise of such exchange right as a result of the Ownership Limit Provisions).

“ Holder ” means any Unit Holder who is the record or beneficial owner of any Registrable Security or any assignee or transferee of such Registrable Security (including assignments or transfers of Registrable Securities to such assignees or

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transferees as a result of the foreclosure on any loans secured by such Registrable Securities) to the extent (a) permitted under the Partnership Agreement or the Articles of Amendment, as applicable, and (b) such assignee or transferee agrees in writing to be bound by all the provisions hereof, unless such Registrable Security is acquired in a public distribution pursuant to a registration statement under the Securities Act or pursuant to transactions exempt from registration under the Securities Act where securities sold in such transaction may be resold without subsequent registration under the Securities Act.

“ Initial Public Offering ” means the offering of the Company’s Common Stock pursuant to the Form S-11 Registration Statement (No. 333-183132) filed by the Company with the Commission under the Securities Act.

“ Indemnified Party ” means an Indemnified Party as defined in Section 2.10.

“ Indemnifying Party ” means an Indemnifying Party as defined in Section 2.10.

“ Inspector ” means an Inspector as defined in Section 2.6.

“ Market Value ” means, with respect to the Common Stock, the average of the daily market price for the 10 consecutive trading days immediately preceding the date of a written request for registration pursuant to Section 2.2(a). The market price for each such trading day shall be: (a) if the Common Stock is listed or admitted to trading on any securities exchange or the National Association of Securities Dealers Automated Quotation (“ NASDAQ ”), the closing price, regular way, on such day, or if no such sale takes place on such day, the average of the closing bid and asked prices on such day, in either case as reported in the principal consolidated transaction reporting system, (b) if the Common Stock is not listed or admitted to trading on any securities exchange or the NASDAQ, the last reported sale price on such day or, if no sale takes place on such day, the average of the closing bid and asked prices on such day, as reported by a reliable quotation source designated by the Company or (c) if the Common Stock is not listed or admitted to trading on any securities exchange or the NASDAQ and no such last reported sale price or closing bid and asked prices are available, the average of the reported high bid and low asked prices on such day, as reported by a reliable quotation source designated by the Company, or if there shall be no bid and asked prices on such day, the average of the high bid and low asked prices, as so reported, on the most recent day (not more than 10 days prior to the date in question) for which prices have been so reported; provided that if there are no bid and asked prices reported during the 10 days prior to the date in question, the Market Value of the Common Stock shall be determined by the board of directors of the Company acting in good faith on the basis of such quotations and other information as it considers, in its reasonable judgment, appropriate.

“ Notice and Questionnaire ” means a written notice, substantially in the form attached as Exhibit A , delivered by a Holder to the Company (i) notifying the Company of such Holder’s desire to include Registrable Securities held by it in a Shelf

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Registration Statement, (ii) containing all information about such Holder required to be included in such Shelf Registration Statement in accordance with applicable law, including Item 507 of Regulation S-K promulgated under the Securities Act, as amended from time to time, or any similar successor rule thereto, and (iii) pursuant to such Holder agrees to be bound by the terms and conditions hereof.

“ Ownership Limit Provisions ” mean the various provisions of the Articles of Amendment set forth in ARTICLE VII thereof restricting the transfer and ownership of Common Stock by Persons to specified percentages of the outstanding Common Stock.

“ Partnership Agreement ” means the Amended and Restated Agreement of Limited Partnership of the Operating Partnership dated as of January 24, 2013, as the same may be amended, modified or restated from time to time.

“ Person ” means an individual or a corporation, partnership, limited liability company, association, trust, or any other entity or organization, including a government or political subdivision or an agency or instrumentality thereof.

“ Piggy-Back Registration ” means a Piggy-Back Registration as defined in Section 2.3.

“ Records ” means Records as defined in Section 2.6.

“ Registrable Securities ” means shares of Common Stock at any time owned, either of record or beneficially, by any Holder and (a) received by such Holder in connection with the Formation Transactions (including, without limitation, the shares acquired in the IPO Stock Issuance) or (b) issued upon exchange of Exchangeable OP Units received by such Holder in the Formation Transactions (including, without limitation, shares of Common Stock issuable upon exchange of Exchangeable OP Units) and, in the case of (a) and (b), any additional Common Stock issued as a dividend, distribution or exchange for, or in respect of such shares until (i) a registration statement covering such shares has been declared effective by the Commission and such shares have been disposed of pursuant to such effective registration statement, (ii) such shares have been publicly sold under Rule 144, (iii) all such shares may be sold in one transaction pursuant to Rule 144 or (iv) such shares have been otherwise transferred in a transaction that constitutes a sale thereof under the Securities Act, the Company has delivered to the Holder’s transferee a new certificate or other evidence of ownership for such shares not bearing the Securities Act restricted stock legend and such shares may be resold or otherwise transferred by such transferee without subsequent registration under the Securities Act.

“ Registration Expenses ” means Registration Expenses as defined in Section 2.7.

“ Requested Shares ” means Requested Shares as defined in Section 2.1.

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“ Rule 144 ” means Rule 144 promulgated under the Securities Act, as amended from time to time, or any similar successor rule thereto that may be promulgated by the Commission.

“ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

“ Selling Holder ” means a Holder who is selling Registrable Securities pursuant to a registration statement under the Securities Act pursuant to the terms hereof.

“ Shelf Registration Statement ” means a Shelf Registration Statement as defined in Section 2.1.

“ Suspension Event ” means a Suspension Event as defined in Section 2.5.

“ Suspension Notice ” means a Suspension Notice as defined in Section 2.5.

“ Underwriter ” means a securities dealer who purchases any Registrable Securities as principal and not as part of such dealer’s market-making activities.

ARTICLE II

REGISTRATION RIGHTS

SECTION 2.1. Shelf Registration .

(a) Preparation and Filing of Shelf Registration Statement . Not later than the date which is 14 months after the consummation date of the Initial Public Offering, the Company shall prepare and file a “shelf” registration statement with respect to the resale of all of the Registrable Securities on an appropriate form for the offering and subsequent resale thereof, to be made on a delayed or continuous basis pursuant to Rule 415 under the Securities Act (the “ Shelf Registration Statement ”) and shall use its commercially reasonable efforts to cause the Shelf Registration Statement to be declared effective on or as soon as practicable thereafter and to keep such Shelf Registration Statement continuously effective for a period ending when all shares of Common Stock covered by the Shelf Registration Statement are no longer Registrable Securities.

At the time the Shelf Registration Statement is declared effective, each Holder that has delivered a duly completed and executed Notice and Questionnaire to the Company on or prior to the date 10 Business Days prior to such time of effectiveness shall be named as a selling securityholder in the Shelf Registration Statement and the related prospectus in such a manner as to permit such Holder to deliver such prospectus to purchasers of Registrable Securities in accordance with applicable law. If required by applicable law, subject to the terms and conditions hereof, after effectiveness of the Shelf Registration Statement, the Company shall file a supplement to such prospectus or amendment to the Shelf Registration Statement not less frequently than once a quarter as necessary to name as selling securityholders therein any Holders that provide to the Company a duly completed and executed Notice and Questionnaire and shall use reasonable efforts to cause any post-effective amendment to such Shelf Registration Statement filed for such purpose to be declared effective by the Commission as promptly as reasonably practicable after the filing thereof.

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(b) Underwritten Shelf Registration . If the Holders of a majority of shares of the Registrable Securities to be registered pursuant to the Shelf Registration Statement so elect by written notice to the Company, the offering of such Registrable Securities pursuant to such Shelf Registration Statement shall be in the form of an underwritten offering; provided that the Registrable Securities requested to be registered in such underwritten offering (the “ Requested Shares ”) shall either (i) have a Market Value of at least $20,000,000 on the date of such request or (ii) represent all remaining Registrable Securities held by such Holders. The Holders of a majority of the Requested Shares shall select the Underwriter or Underwriters to serve as book-running manager or managers in connection with any such offering; provided that such managing Underwriter or Underwriters must be reasonably satisfactory to the Company. The Holders of a majority of the Requested Shares may select any additional investment banks and managers to be used in connection with the offering; provided that such additional investment bankers and managers must be reasonably satisfactory to the Company.

(c) Filing of Additional Registration Statements . The Company shall prepare and file such additional registration statements as necessary every three years and use its reasonable efforts to cause such registration statements to be declared effective by the Commission so that the registration statement remains continuously effective with respect to resales of Registrable Securities as of and for the periods required under Section 2.1(a) hereof, such subsequent registration statements to constitute a Shelf Registration Statement hereunder.

SECTION 2.2. Demand Registration .

(a) Request for Registration . In the event that the Company fails to file, or if filed fails to maintain the effectiveness of, a Shelf Registration Statement, Holders of Registrable Securities may make a written request for registration under the Securities Act of all or part of their Registrable Securities (a “ Demand Registration ”); provided , that if and so long as a Shelf Registration Statement is on file and effective, then the Company shall have no obligation to effect a Demand Registration; and provided further , that the number of shares of Registrable Securities proposed to be sold by the Holders making such written request for a Demand Registration shall either (i) have a Market Value of at least $20,000,000 on the date of such request or (ii) shall represent all remaining Registrable Securities held by such Holders. The number of Demand Registrations which may be made pursuant to this Section 2.2(a) shall be unlimited; provided that the Company shall not be obligated to effect more than three Demand Registrations in any 12-month period. Any request for a Demand Registration will specify the number of shares of Registrable Securities proposed to be sold and will also specify the intended method of disposition thereof. Within 10 days after receipt of such request, the Company will give written notice of such registration request to all other Holders of the Registrable Securities and include in such registration all such Registrable Securities with respect to which the Company has received written requests for inclusion

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therein within 20 Business Days after the receipt by the applicable Holder of the Company’s notice. Each such request will also specify the number of shares of Registrable Securities to be registered and the intended method of disposition thereof. Unless the Holder or Holders of a majority of the Registrable Securities to be registered in such Demand Registration shall consent in writing, no other party, including the Company (but excluding another Holder of a Registrable Security), shall be permitted to offer securities under any such Demand Registration.

(b) Effective Registration . A registration will not count as a Demand Registration until it has become effective.

(c) Selling Holders Become Party to Agreement . Each Holder acknowledges that by asserting or participating in its registration rights pursuant to this Agreement, such Holder may become a Selling Holder and thereby will be deemed a party to this Agreement and will be bound by each of its terms.

(d) Underwritten Demand Registrations . If the Holders of a majority of shares of the Registrable Securities to be registered in a Demand Registration so elect by written notice to the Company, the offering of such Registrable Securities pursuant to such Demand Registration shall be in the form of an underwritten offering. The Holders of a majority of the shares of Registrable Securities participating in the Demand Registration shall select the Underwriter or Underwriters to serve as book-running manager or managers in connection with any such Demand Registration; provided that such managing Underwriter or Underwriters must be reasonably satisfactory to the Company. The Holders of a majority of the shares of the Registrable Securities participating in the Demand Registration may select any additional investment banks and managers to be used in connection with the offering; provided that such additional investment bankers and managers must be reasonably satisfactory to the Company. To the extent 10% or more of the Registrable Securities requested to be registered in any such Demand Registration are excluded from the offering in accordance with Section 2.4, the Holders of such Registrable Securities shall have the right to one additional Demand Registration under this Section in such 12-month period with respect to such Registrable Securities.

SECTION 2.3. Piggy-Back Registration . If the Company proposes to file a registration statement under the Securities Act with respect to an underwritten equity offering of Common Stock by the Company for its own account or for the account of any of its respective securityholders (other than (a) any registration statement filed by the Company under the Securities Act relating to an offering of Common Stock for its own account as a result of the exercise of the exchange rights set forth in Section 15.1 of the Partnership Agreement, (b) any registration statement filed in connection with a demand registration other than a Demand Registration under this Agreement or (c) a registration statement on Form S-4 or S-8 (or any substitute form that may be adopted by the Commission) or filed in connection with an exchange offer or offering of securities solely to the Company’s existing securityholders), then the Company shall give written notice of such proposed filing to the Holders of Registrable Securities as soon as practicable (but in no event less than 10 days before the anticipated filing date), and such notice shall

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offer such Holders the opportunity to register such number of shares of Registrable Securities as each such Holder may request (a “ Piggy-Back Registration ”). The Company shall use its commercially reasonable efforts to cause the managing Underwriter or Underwriters of a proposed underwritten offering to permit the Registrable Securities requested to be included in a Piggy-Back Registration to be included on the same terms and conditions as any similar securities of the Company included therein.

SECTION 2.4. Reduction of Offering . Notwithstanding anything contained herein, if the managing Underwriter or Underwriters of an offering described in Sections 2.1(b), 2.2(d) or 2.3 advise in writing to the Company and the Holders of the Registrable Securities included in such offering that (a) the size of the offering that the Holders, the Company and such other persons intend to make or (b) in the case of a Piggy-Back Registration only, the kind of securities that the Holders, the Company and/or any other persons or entities intend to include in such offering are such that the success of the offering would be materially and adversely affected by inclusion of the Registrable Securities requested to be included, then (i) if the size of the offering is the basis of such Underwriter’s determination, the amount of securities to be offered for the accounts of Holders shall be reduced pro rata (according to the Registrable Securities proposed for registration) to the extent necessary to reduce the total amount of securities to be included in such offering to the amount recommended by such managing Underwriter or Underwriters; provided that, in the case of a Piggy-Back Registration, if securities of a different class are being offered for the account of other persons or entities as well as the Company, then with respect to the Registrable Securities intended to be offered by Holders, the proportion by which the amount of such class of securities intended to be offered by Holders is reduced shall not exceed the proportion by which the amount of such class of securities intended to be offered by such other persons or entities is reduced; and (ii) if the kind of securities to be offered is the basis of such Underwriter’s determination, (A) the Registrable Securities to be included in such offering shall be reduced as described in clause (i) above (subject to the proviso in clause (i)) or, (B) if the actions described in clause (A) would, in the commercially reasonable judgment of the managing Underwriter, be insufficient to substantially eliminate the adverse effect that inclusion of the Registrable Securities requested to be included would have on such offering, such Registrable Securities will be excluded from such offering.

SECTION 2.5. Black-Out Periods

(a) Notwithstanding the provisions of Sections 2.1(a), 2.1(b), 2.2(a), and 2.2(d), the Company shall be permitted to postpone the filing of any Shelf Registration Statement filed pursuant to Section 2.1 or any registration statement filed in connection with a Demand Registration pursuant to Section 2.2 hereof, and from time to time to require the Holders not to sell Registrable Securities under any such Shelf Registration Statement or other registration statement or to suspend the effectiveness thereof, for such times as the Company reasonably may determine is necessary and advisable (but in no event shall the Company be entitled to exercise such right more than two times or for more than an aggregate of 90 days in any rolling 12-month period commencing on the date of this Agreement), if any of the following events shall occur (each such

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circumstance a “ Suspension Event ”): (i) a majority of the board of directors of the Company determines in good faith that (A) the offer or sale of any Registrable Securities would materially impede, delay or interfere with any proposed financing, offer or sale of securities, acquisition, corporate reorganization or other material transaction involving the Company, (B) upon the advice of counsel, the sale of Registrable Securities pursuant to such Shelf Registration Statement or other registration statement would require disclosure of non-public material information not otherwise required to be disclosed under applicable law or (C)(x) the Company has a bona fide business purpose for preserving the confidentiality of a material transaction, (y) disclosure would have a material adverse effect on the Company or the Company’s ability to consummate such a material transaction or (z) such a material transaction renders the Company unable to comply with Commission requirements, in each case under circumstances that would make it impractical or inadvisable, based on the advice of counsel, to cause the Shelf Registration Statement or other registration statement (or such filings) to become effective or to promptly amend or supplement the Shelf Registration Statement or other registration statement on a post-effective basis, as applicable; or (ii) a majority of the board of directors of the Company determines in good faith, upon the advice of counsel, that it is in the Company’s best interest or it is required by law, rule or regulation to supplement the Shelf Registration Statement or other registration statement or file a post-effective amendment to such Shelf Registration Statement or other registration statement in order to ensure that the prospectus included in the Shelf Registration Statement or other registration statement (1) contains the information required by the form on which such Shelf Registration Statement or other registration statement was filed or (2) discloses any facts or events arising after the effective date of the Shelf Registration Statement or other registration statement (or of the most recent post-effective amendment) that, individually or in the aggregate, represents a fundamental change in the information set forth therein. Upon the occurrence of any such suspension, the Company shall use its commercially reasonable efforts to cause the Shelf Registration Statement or other registration statement to become effective or to amend or supplement the Shelf Registration Statement or other registration statement on a post-effective basis or to take such action as is necessary to permit resumed use of the Shelf Registration Statement or other registration statement or filing thereof as soon as reasonably possible following the conclusion of the applicable Suspension Event and its effect.

The Company will provide written notice (a “ Suspension Notice ”) to the Holders of the occurrence of any Suspension Event. Upon receipt of a Suspension Notice, each Holder agrees that it will (i) immediately discontinue offers and sales of the Registrable Securities under the Shelf Registration Statement or other registration statement and (ii) maintain the confidentiality of any information included in the Suspension Notice unless otherwise required by law or subpoena. The Holders may recommence effecting offers and sales of the Registrable Securities pursuant to the Shelf Registration Statement or other registration statement (or such filings) following further written notice to such effect (an “ End of Suspension Notice ”) from the Company, which End of Suspension Notice shall be given by the Company to the Holders promptly following the conclusion of any Suspension Event and its effect; provided that the Holders agree that they will only effect such offers and sales pursuant to any supplemental or amended prospectus that has been provided to them by the Company pursuant to Section 2.5(b).

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(b) Notwithstanding any provision herein to the contrary, if the Company shall give a Suspension Notice with respect to any Shelf Registration Statement or other registration statement pursuant to Section 2.5(a), the Company agrees that it shall extend the period of time during which such Shelf Registration Statement or other registration statement shall be maintained effective (including the period referred to in Section 2.6(a) hereof) by the number of days during the period from the date of receipt by the Holders of the Suspension Notice to and including the date of receipt by the Holders of the End of Suspension Notice and promptly provide copies of the supplemented or amended prospectus necessary to resume offers and sales, with respect to each Suspension Event; provided , that such period of time shall not be extended beyond the date that the shares of Common Stock covered by such Shelf Registration Statement or other registration statement are no longer Registrable Securities.

SECTION 2.6. Registration Procedures; Filings; Information . Subject to Section 2.5 hereof, in connection with any Shelf Registration Statement under Section 2.1 or any Demand Registration under Section 2.2 hereof, the Company will use its commercially reasonable efforts to effect the registration and the sale of such Registrable Securities in accordance with the intended method of disposition thereof as quickly as practicable, and in connection with any such request:

(a) The Company will as expeditiously as possible prepare and file with the Commission a registration statement on any form for which the Company then qualifies or which counsel for the Company shall deem appropriate and which form shall be available for the sale of the Registrable Securities to be registered thereunder in accordance with the intended method of distribution thereof, and use its commercially reasonable efforts to cause such filed registration statement to become and remain effective (i) in the case of a Shelf Registration Statement, for the period described in Section 2.1 and (ii) in the case of a Demand Registration, for a period of not less than 270 days from the effective date of such registration statement.

(b) The Company will, if requested, prior to filing a registration statement or prospectus or any amendment or supplement thereto, furnish to each Selling Holder and each Underwriter, if any, of the Registrable Securities covered by such registration statement copies of such registration statement as proposed to be filed, and thereafter furnish to such Selling Holder and Underwriter, if any, such number of conformed copies of such registration statement, each amendment and supplement thereto (and upon request, all exhibits thereto and documents incorporated by reference therein), the prospectus included in such registration statement (including each preliminary prospectus) and such other documents as such Selling Holder or Underwriter may reasonably request in order to facilitate the disposition of the Registrable Securities owned by such Selling Holder.

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(c) After the filing of the registration statement, the Company will promptly notify each Selling Holder of Registrable Securities covered by such registration statement of any stop order issued or threatened by the Commission and take all reasonable actions required to prevent the entry of such stop order or to remove it if entered.

(d) The Company will use its commercially reasonable efforts to (i) register or qualify the Registrable Securities under such other securities or blue sky laws of such jurisdictions in the United States (where an exemption does not apply) as any Selling Holder or managing Underwriter or Underwriters, if any, reasonably (in light of such Selling Holder’s intended plan of distribution) requests and (ii) cause such Registrable Securities to be registered with or approved by such other governmental agencies or authorities as may be necessary by virtue of the business and operations of the Company and do any and all other acts and things that may be reasonably necessary or advisable to enable such Selling Holder to consummate the disposition of the Registrable Securities owned by such Selling Holder; provided that the Company will not be required to (A) qualify generally to do business in any jurisdiction where it would not otherwise be required to qualify but for this paragraph (d), (B) subject itself to taxation in any such jurisdiction or (C) consent to general service of process in any such jurisdiction.

(e) The Company will immediately notify each Selling Holder of such Registrable Securities, at any time when a prospectus relating thereto is required to be delivered under the Securities Act, of (i) the Company’s receipt of any notification of the suspension of the qualification of any Registrable Securities covered by a Shelf Registration Statement for sale in any jurisdiction or (ii) the occurrence of an event requiring the preparation of a supplement or amendment to such prospectus so that, as thereafter delivered to the purchasers of such Registrable Securities, such prospectus will not contain an untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading and promptly make available to each Selling Holder any such supplement or amendment.

(f) The Company will enter into customary agreements (including an underwriting agreement, if any, in customary form) and take such other actions as are reasonably required in order to expedite or facilitate the disposition of such Registrable Securities.

(g) The Company will make available for inspection by any Selling Holder of such Registrable Securities, if such Selling Holder has a due diligence defense under the Securities Act, any Underwriter participating in any disposition pursuant to such registration statement and any attorney, accountant or other professional retained by any such Selling Holder or Underwriter (collectively, the “ Inspectors ”), all financial and other records, pertinent corporate documents and properties of the Company (collectively, the “ Records ”) as shall be reasonably necessary to enable them to exercise their due diligence responsibility, and cause the Company’s officers, directors and employees to supply all information reasonably requested by any Inspector in connection with such registration statement, subject to entry by each such Inspector into a customary confidentiality agreement in a form reasonably acceptable to the Company.

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(h) The Company will furnish to each Selling Holder, if it has a due diligence defense under the Securities Act, and to each Underwriter, if any, a signed counterpart, addressed to such Selling Holder or Underwriter, of (i) an opinion or opinions of counsel to the Company and (ii) if eligible under SAS 72, a comfort letter or comfort letters from the Company’s independent public accountants, each in customary form and covering such matters of the type customarily covered by opinions or comfort letters, as the case may be, as the Holders of a majority of the Registrable Securities included in such offering or the managing Underwriter or Underwriters therefor reasonably requests.

(i) The Company will otherwise use its commercially reasonable efforts to comply with all applicable rules and regulations of the Commission, and make available to its securityholders, as soon as reasonably practicable, an earnings statement covering a period of 12 months, beginning within three months after the effective date of the registration statement, which earnings statement shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158 of the Commission promulgated thereunder (or any successor rule or regulation hereafter adopted by the Commission).

(j) The Company will use its commercially reasonable efforts to cause all such Registrable Securities to be listed on each securities exchange on which similar securities issued by the Company are then listed.

The Company may require each Selling Holder of Registrable Securities to promptly furnish in writing to the Company such information regarding such Selling Holder, the Registrable Securities held by it and the intended method of distribution of the Registrable Securities as the Company may from time to time reasonably request and such other information as may be legally required in connection with such registration.

Each Selling Holder agrees that, upon receipt of any notice from the Company of the happening of any event of the kind described in Section 2.6(e) hereof, such Selling Holder will forthwith discontinue disposition of Registrable Securities pursuant to the registration statement covering such Registrable Securities until such Selling Holder’s receipt of written notice from the Company that such disposition may be made and, in the case of clause (ii) of Section 2.6(e) hereof, copies of the supplemented or amended prospectus contemplated by clause (ii) of Section 2.6(e) hereof, and, if so directed by the Company, such Selling Holder will deliver to the Company all copies, other than permanent file copies then in such Selling Holder’s possession, of the most recent prospectus covering such Registrable Securities at the time of receipt of such notice. Each Selling Holder of Registrable Securities agrees that it will immediately notify the Company at any time when a prospectus relating to the registration of such Registrable Securities is required to be delivered under the Securities Act of the happening of an event as a result of which information previously furnished by such Selling Holder to the Company in writing for inclusion in such prospectus contains an untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make the statements therein not misleading in light of the circumstances in which they were made. In the event the Company shall give such notice, the Company shall extend the period during which such registration statement shall be

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maintained effective (including the period referred to in Section 2.6(a) hereof) by the number of days during the period from and including the date of the giving of notice pursuant to Section 2.6(e) hereof to the date when the Company shall provide written notice that such dispositions may be made and, in the case of clause (ii) of Section 2.6(e) hereof, make available to the Selling Holders of Registrable Securities covered by such registration statement a prospectus supplemented or amended to conform with the requirements of Section 2.6(e) hereof.

SECTION 2.7. Registration Expenses . In connection with any registration statement required to be filed hereunder, the Company shall pay the following registration expenses incurred in connection with the registration hereunder (the “ Registration Expenses ”), regardless of whether such registration statement is declared effective by the Commission: (a) all registration and filing fees, (b) fees and expenses of compliance with securities or blue sky laws (including reasonable fees and disbursements of counsel in connection with blue sky qualifications of the Registrable Securities), (c) printing expenses, (d) internal expenses (including, without limitation, all salaries and expenses of its officers and employees performing legal or accounting duties), (e) the fees and expenses incurred in connection with the listing of the Registrable Securities, (f) reasonable fees and disbursements of counsel for the Company and customary fees and expenses for independent certified public accountants retained by the Company (including the expenses of any comfort letters or costs associated with the delivery by independent certified public accountants of a comfort letter or comfort letters requested pursuant to Section 2.6(h) hereof), (g) the reasonable fees and disbursement of one counsel for all the Holders and (h) the reasonable fees and expenses of any special experts retained by the Company in connection with such registration. The Company shall have no obligation to pay any underwriting fees, discounts or commissions attributable to the sale of Registrable Securities or any transfer taxes relating to the registration or sale of the Registrable Securities.

SECTION 2.8. Indemnification by the Company . The Company agrees to indemnify and hold harmless each Selling Holder of Registrable Securities, its officers, directors and agents, and each Person, if any, who controls such Selling Holder within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act from and against any and all losses, claims, damages and liabilities that arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in any registration statement or prospectus relating to such Registrable Securities, or any amendment or supplement thereto, or any preliminary prospectus, or that arise out of or are based upon any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, except insofar as such losses, claims, damages or liabilities that arise out of or are based upon any such untrue statement or omission or alleged untrue statement or omission included in reliance upon and in conformity with information furnished in writing to the Company by such Selling Holder or on such Selling Holder’s behalf expressly for inclusion therein. The Company also agrees to indemnify any Underwriters of the Registrable Securities, their officers and directors and each Person who controls such underwriters within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act on substantially the

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same basis as that of the indemnification of the Selling Holders provided in this Section 2.8; provided that the foregoing indemnity with respect to any preliminary prospectus shall not inure to the benefit of any Underwriter of the Registrable Securities from whom the person asserting any such losses, claims, damages or liabilities purchased the Registrable Securities which are the subject thereof if such person did not receive a copy of the prospectus (or the prospectus as supplemented) at or prior to the confirmation of the sale of such Registrable Securities to such person in any case where such delivery is required by the Securities Act and the untrue statement or omission of a material fact contained in such preliminary prospectus was corrected in the prospectus (or the prospectus as supplemented).

SECTION 2.9. Indemnification by Holders of Registrable Securities . Each Selling Holder agrees, severally but not jointly, to indemnify and hold harmless the Company, its officers, directors and agents and each Person, if any, who controls the Company within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the foregoing indemnity from the Company to such Selling Holder pursuant to Section 2.8, but only with respect to information relating to such Selling Holder included in reliance upon and in conformity with information furnished in writing by such Selling Holder or on such Selling Holder’s behalf expressly for use in any registration statement or prospectus relating to the Registrable Securities, or any amendment or supplement thereto, or any preliminary prospectus. In case any action or proceeding shall be brought against the Company or its officers, directors or agents or any such controlling person, in respect of which indemnity may be sought against such Selling Holder, such Selling Holder shall have the rights and duties given to the Company, and the Company or its officers, directors or agents or such controlling person shall have the rights and duties given to such Selling Holder, by Section 2.8. Each Selling Holder also agrees to indemnify and hold harmless Underwriters of the Registrable Securities, their officers and directors and each Person who controls such Underwriters within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act on substantially the same basis as that of the indemnification of the Company provided in this Section 2.9. Notwithstanding the foregoing, in no event will the liability of a Selling Holder under this Section 2.9 or Section 2.11 or otherwise hereunder exceed the net proceeds actually received by such Selling Holder.

SECTION 2.10. Conduct of Indemnification Proceedings . In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to Section 2.8 or 2.9, such person (an “ Indemnified Party ”) shall promptly notify the person against whom such indemnity may be sought (an “ Indemnifying Party ”) in writing and the Indemnifying Party shall assume the defense thereof, including the employment of counsel reasonably satisfactory to such Indemnified Party, and shall assume the payment of all fees and expenses; provided that the failure of any Indemnified Party to give such notice will not relieve such Indemnifying Party of its obligations under Section 2.8 or 2.9, as applicable, except to the extent such Indemnifying Party is materially prejudiced by such failure. In any such proceeding, any Indemnified Party shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such Indemnified Party unless (a) the Indemnifying Party and the Indemnified Party shall have mutually

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agreed to the retention of such counsel or (b) the named parties to any such proceeding (including any impleaded parties) include both the Indemnified Party and the Indemnifying Party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood that the Indemnifying Party shall not, in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonable fees and expenses of more than one separate firm of attorneys (in addition to any local counsel) at any time for all such Indemnified Parties, and that all such fees and expenses shall be reimbursed as they are incurred. In the case of any such separate firm for the Indemnified Parties, such firm shall be designated in writing by (i) in the case of Persons indemnified pursuant to Section 2.8 hereof, the Selling Holders which owned a majority of the Registrable Securities sold under the applicable registration statement and (ii) in the case of Persons indemnified pursuant to Section 2.9, the Company. The Indemnifying Party shall not be liable for any settlement of any proceeding effected without its written consent, which consent shall not be unreasonably withheld, but if settled with such consent, or if there be a final judgment for the plaintiff, the Indemnifying Party shall indemnify and hold harmless such Indemnified Parties from and against any loss or liability (to the extent stated above) by reason of such settlement or judgment. No Indemnifying Party shall, without the prior written consent of the Indemnified Party (which consent shall not be unreasonably withheld, conditioned or delayed), effect any settlement of any pending or threatened proceeding in respect of with any Indemnified Party is or could have been a party and indemnity could have been sought hereunder by such Indemnified Party, unless such settlement includes an unconditional release of such Indemnified Party from all liability arising out of such proceeding without any admission of liability by such Indemnified Party.

SECTION 2.11. Contribution . If the indemnification provided for in Section 2.8 or 2.9 hereof is held by a court of competent jurisdiction to be unavailable to an Indemnified Party or insufficient in respect of any losses, claims, damages or liabilities referred to herein, then each such Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such losses, claims, damages or liabilities (a) as between the Company and the Selling Holders on the one hand and the Underwriters on the other, in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Holders on the one hand and the Underwriters on the other from the offering of the securities, or if such allocation is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits but also the relative fault of the Company and the Selling Holders on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations and (b) between the Company on the one hand and each Selling Holder on the other, in such proportion as is appropriate to reflect the relative fault of the Company and of each Selling Holder in connection with such statements or omissions which resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company and the Selling Holders on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total proceeds from the offering (net of underwriting discounts

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and commissions but before deducting expenses) received by the Company and the Selling Holders bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the prospectus. The relative fault of the Company and the Selling Holders on the one hand and of the Underwriters on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company and the Selling Holders or by the Underwriters. The relative fault of the Company on the one hand and of each Selling Holder on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by such party, and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The Company and the Selling Holders agree that it would not be just and equitable if contribution pursuant to this Section 2.11 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in the immediately preceding paragraph. The amount paid or payable by an Indemnified Party as a result of the losses, claims, damages or liabilities referred to in the immediately preceding paragraph shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 2.11, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission, and no Selling Holder shall be required to contribute any amount in excess of the amount by which the total price at which the securities of such Selling Holder were offered to the public exceeds the amount of any damages which such Selling Holder has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Selling Holder’s obligations to contribute pursuant to this Section 2.11 are several in such proportion that the proceeds of the offering received by such Selling Holder bears to the total proceeds of the offering received by all the Selling Holders, and not joint. For the avoidance of doubt, this Section 2.11 applies in the case of a “shelf” registration and an underwritten offering.

SECTION 2.12. Participation in Underwritten Offerings . No Person may participate in any underwritten offering hereunder unless such Person (a) agrees to sell such Person’s securities on the basis provided in any underwriting arrangements approved by the Persons entitled hereunder to approve such arrangements and (b) completes and executes all questionnaires, powers of attorney, indemnities, underwriting agreements and other documents reasonably required under the terms of such underwriting arrangements and the registration rights provided for in this Article II.

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SECTION 2.13. Rule 144 . The Company covenants that it will timely file any reports required to be filed by it under the Securities Act and the Exchange Act and that it will take such further action as any Holder may reasonably request, all to the extent required from time to time to enable Holders to sell Registrable Securities without registration under the Securities Act within the limitation of the exemptions provided by Rule 144. Upon the request of any Holder, the Company will deliver to such Holder a written statement as to whether it has complied with such requirements.

SECTION 2.14. Holdback Agreements .

(a) Restrictions on Public Sale by Holder of Registrable Securities . To the extent not inconsistent with applicable law, each Holder whose securities are included in a registration statement agrees not to effect any sale or distribution of the issue being registered or a similar security of the Company, or any securities convertible into or exchangeable or exercisable for such securities, including a sale pursuant to Rule 144, during the 14 days prior to, and during the 90-day period beginning on, the effective date of such registration statement (except as part of such registration), if and to the extent requested in writing by the Company in the case of a non-underwritten public offering or if and to the extent requested in writing by the managing Underwriter or Underwriters and consented to by the Company, which consent may be given or withheld in the Company’s sole and absolute discretion, in the case of an underwritten public offering (such agreement to be in the form of lock-up agreement provided by the managing Underwriter or Underwriters).

(b) Restrictions on Public Sale by the Company and Others . The Company agrees that any agreement entered into after the date of this Agreement pursuant to which the Company issues or agrees to issue any privately placed securities shall contain a provision under which holders of such securities agree not to effect any sale or distribution of any securities similar to those being registered in accordance with Section 2.1, 2.2 or 2.3 hereof, or any securities convertible into or exchangeable or exercisable for such securities, during the 14 days prior to, and during the 90-day period beginning on, the effective date of any registration statement (except as part of such registration statement where the Holders of a majority of the Registrable Securities to be included in such registration statement consent or as part of registration statements filed as set forth in Section 2.3(a) or (c)), if and to the extent requested in writing by the Company in the case of a non-underwritten public offering or if and to the extent requested in writing by the managing Underwriter or Underwriters and consented to by the Company, which consent shall not be unreasonably withheld, conditioned or delayed, in the case of an underwritten public offering (such agreement to be in the form of lock-up agreement provided by the managing Underwriter or Underwriters), in each case including a sale pursuant to Rule 144 (except as part of any such registration, if permitted); provided , however, that the provisions of this paragraph (b) shall not prevent the conversion or exchange of any securities pursuant to their terms into or for other securities.

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ARTICLE III

MISCELLANEOUS

SECTION 3.1. NASDAQ Listing . In the event that the Company shall issue any Common Stock in exchange for OP Units pursuant to Section 15.1 of the Partnership Agreement, then in any such case the Company agrees to cause any such shares of Common Stock, in addition to the shares of Common Stock issued in connection with the IPO Stock Issuance, to be listed on the NASDAQ or such other exchange on which the Common Stock may then be listed prior to or concurrently with the issuance thereof by the Company.

SECTION 3.2. Remedies . In addition to being entitled to exercise all rights provided herein and granted by law, including recovery of damages, the Holders shall be entitled to specific performance of the rights under this Agreement. The Company agrees that monetary damages would not be adequate compensation for any loss incurred by reason of a breach by it of the provisions of this Agreement and hereby agrees to waive the defense in any action for specific performance that a remedy at law would be adequate. Notwithstanding the foregoing, specific performance shall not be available with respect to the rights and obligations of the parties pursuant to Section 2.14(a) and (b).

SECTION 3.3. Amendments and Waivers . The provisions of this Agreement, including the provisions of this sentence, may not be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given, in each case without the written consent of the Company and the Holders of a majority of the Registrable Securities. No failure or delay by any party to insist upon the strict performance of any covenant, duty, agreement or condition of this Agreement or to exercise any right or remedy consequent upon any breach thereof shall constitute waiver of any such breach or any other covenant, duty, agreement or condition.

SECTION 3.4. Notices . All notices and other communications in connection with this Agreement shall be made in writing by hand delivery, registered first-class mail, telecopier, or air courier guaranteeing overnight delivery:

(a) if to the Holders, initially c/o Cincinnati Bell Inc. initially at 221 East Fourth Street, Cincinnati, OH 45202 (Attention: General Counsel, Facsimile: (513) 397-9900), or to such other address and to such other Persons as any Holder may hereafter specify in writing; and

(b) if to the Company, initially at 1649 West Frankford Road, Carrollton, TX 75007 (Attention: General Counsel, Facsimile: (972) 350-0061), or to such other address as the Company may hereafter specify in writing.

All such notices and communications shall be deemed to have been duly given: at the time delivered by hand, if personally delivered; when received if deposited in the mail, postage prepaid, if mailed; when receipt is acknowledged, if telecopied; and on the next business day, if timely delivered to an air courier guaranteeing overnight delivery.

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SECTION 3.5. Successors and Assigns . Except as expressly provided in this Agreement, the rights and obligations of the Holders under this Agreement shall not be assignable by any Holder to any Person that is not a Holder. This Agreement shall be binding upon the parties hereto and their respective successors and assigns.

SECTION 3.6. Counterparts . This Agreement may be executed in any number of counterparts and by the parties hereto in separate counterparts, each of which when so executed shall be deemed to be an original and all of which taken together shall constitute one and the same agreement. Each party shall become bound by this Agreement immediately upon affixing its signature hereto.

SECTION 3.7. Governing Law . This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York without regard to the choice of law provisions thereof.

SECTION 3.8. Severability . In the event that any one or more of the provisions contained herein, or the application thereof in any circumstance, is held invalid, illegal or unenforceable, the validity, legality and enforceability of any such provision in every other respect and of the remaining provisions contained herein shall not be affected or impaired thereby.

SECTION 3.9. Entire Agreement . This Agreement is intended by the parties as a final expression of their agreement and intended to be a complete and exclusive statement of the agreement and understanding of the parties hereto in respect of the subject matter contained herein. There are no restrictions, promises, warranties or undertakings, other than those set forth or referred to herein with respect to the registration rights granted by the Company with respect to the Registrable Securities. This Agreement supersedes all prior agreements and understandings between the parties with respect to such subject matter.

SECTION 3.10. Headings . The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof.

SECTION 3.11. No Third Party Beneficiaries . Nothing express or implied herein is intended or shall be construed to confer upon any person or entity, other than the parties hereto and their respective successors and assigns and all Indemnified Parties, any rights, remedies or other benefits under or by reason of this Agreement.

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

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