PROSPECTUS SUMMARY

You should read the following summary together with the more detailed information regarding our company and the historical and pro forma financial statements appearing elsewhere in this prospectus, including under the caption “Risk Factors.” Except as otherwise indicated, references in this prospectus to (i) “CyrusOne,” “we,” “our,” “us” and “our company” refer to CyrusOne Inc., a Maryland corporation, together with our consolidated subsidiaries, including CyrusOne LP, a Maryland limited partnership, which we refer to in this prospectus as our operating partnership, and CyrusOne GP, a Maryland statutory trust of which we are the sole beneficial owner and which is the sole general partner of our operating partnership, (ii) “CBI” refers to Cincinnati Bell Inc., an Ohio corporation, and, unless the context otherwise requires, its consolidated subsidiaries, and (iii) “Predecessor” refers to the carve-out business that is comprised of the historical data center activities of CBI, the financial statements of which are included in this prospectus. Unless otherwise indicated, the information contained in this prospectus is as of September 30, 2012, assumes that the underwriters’ over-allotment option is not exercised and gives effect to an approximately 2.8-to-1 operating partnership unit reverse split immediately prior to the completion of this offering. Information related to the consideration to acquire our initial properties and with respect to uses of proceeds is estimated as of the anticipated consummation of this offering, the formation transactions and the related financing transactions.

CyrusOne Inc.

Our Company

We are an owner, operator and developer of enterprise-class, carrier-neutral data center properties. Enterprise-class, carrier-neutral data centers are purpose-built facilities with redundant power, cooling and telecommunications systems and that are not network-specific, enabling customer interconnectivity to a range of telecommunications carriers.

We provide mission-critical data center facilities that protect and ensure the continued operation of information technology (“IT”) infrastructure for approximately 500 customers. Our goal is to be the preferred global data center provider to the Fortune 1000. As of September 30, 2012, our customers included nine of the Fortune 20 and 108 of the Fortune 1000 or private or foreign enterprises of equivalent size. These 108 customers provided 79% of our annualized rent as of September 30, 2012. Additionally, as of September 30, 2012, our top 10 customers (including CBI) provided 46% of our annualized rent.

We cultivate long-term strategic relationships with our customers and provide them with solutions for their data center facilities and IT infrastructure challenges. Our offerings provide flexibility, reliability and security and are delivered through a tailored, customer service-focused platform that is designed to foster long-term relationships. We focus on attracting customers that have not historically outsourced their data center needs. We believe our capabilities and reputation for serving the needs of large enterprises will allow us to capitalize on the growing demand for outsourced data center facilities in our markets and in new markets where our customers are located or plan to be located in the future.

Our History

Our business is comprised of the historical data center activities and holdings of CBI. CBI has operated its Cincinnati-based data center business for over 10 years; in addition, it acquired GramTel Inc. (“GramTel”), a data center operator in South Bend, Indiana and Chicago, Illinois, for approximately $20 million in December 2007; and it acquired Cyrus Networks, LLC (“Cyrus Networks”), a data center operator based in Texas, for approximately $526 million, net of cash acquired, in June 2010. As part of the formation transactions, certain subsidiaries of CBI contributed these assets and operations to our operating partnership, CyrusOne LP.

Our Portfolio

As of September 30, 2012, our property portfolio included 23 operating data centers in nine distinct markets (Austin, Chicago, Cincinnati, Dallas, Houston, London, San Antonio, Singapore and South Bend), collectively providing approximately 1,630,000 net rentable square feet (“NRSF”) and powered by approximately 125 megawatts (“MW”) of utility power. We own nine of the buildings in which our data center facilities are located. We lease the remaining 14 buildings, which account for approximately 600,000 NRSF, or approximately 37% of our total operating NRSF. These leased buildings accounted for 36% of our total annualized rent as of September 30, 2012 and 37% of our total NOI for the three months then ended. We also currently have 379,000 NRSF under development at three data centers in three distinct markets (Dallas, Houston and Phoenix) and 762,000 NRSF of additional powered shell space under roof and available for development. In addition, we have approximately 146 acres of land that are available for future data center facility development. Along with our primary product offering, leasing of colocation space, our customers are increasingly interested in our ancillary office and other space, which is listed separately in the table below. We believe our existing operating portfolio and development pipeline will allow us to meet the evolving needs of our existing customers and continue to attract new customers.

The following tables provide an overview of our operating and development properties as of September 30, 2012, after giving effect to the formation transactions.

During the third quarter of 2012, we added 36,000 CSF at our Westover Hills Blvd (San Antonio) facility, 47,000 CSF at our Frankford Road (Carrollton) facility and 15,000 CSF at our Westway Park Blvd (Houston West) facility. This additional capacity increased our CSF by 12% in the quarter, causing our percent leased NRSF to decrease from 85% at June 30, 2012 to 79% at September 30, 2012. The book value of our properties on which development has commenced, or has recently been completed, or that are held for future development was approximately $130 million as of September 30, 2012.

The development of the 36,000 CSF under development at our South Ellis Street (Phoenix) facility was completed in the fourth quarter of 2012. We anticipate that the development of the powered shell at this facility will be completed in the first quarter of 2013. We anticipate that the 157,000 NRSF under development at our Westway Park Blvd (Houston West) facility will be completed in the first half of 2013.

Industry Overview

Data centers are highly specialized facilities that serve as centralized repositories of server, storage and network equipment and are designed to provide the space, power, cooling and network connectivity necessary to efficiently operate mission-critical IT equipment.

Gartner, Inc. estimates that the global market for data center services was approximately $150 billion in 2011 and will grow to approximately $200 billion in 2012.

The demand for data center infrastructure is being driven by many factors, but most importantly by significant Internet traffic growth and the increased demand for outsourcing.

In addition to these strong demand dynamics, the data center market has other key favorable characteristics for existing data center operators:

Our Competitive Strengths

We believe the following competitive strengths distinguish us from other data center operators and will enable us to continue to grow our operations.

High Quality Customer Base. The high quality of our assets combined with our reputation for serving the needs of large enterprises has enabled us to focus on the Fortune 1000 to build a quality customer base. We currently have approximately 500 customers from a broad spectrum of industries, with a particular expertise serving the energy industry, which comprises 38% of our annualized rent as of September 30, 2012. We currently have nine of the Fortune 20 and 108 of the Fortune 1000 or private or foreign enterprises of equivalent size as customers, including five of the six “supermajor” oil and gas companies. Our revenue is generated by a stable enterprise customer base, as evidenced by the following as of September 30, 2012:

As of September 30, 2012, CBI represented 10% of our annualized rent under contracts, which is largely comprised of two customers to whom we provide services through contracts entered into between those customers and Cincinnati Bell Technology Solutions Inc., a subsidiary of CBI (“CBTS”). Customer consent is required in order to assign those contracts to us, and while we expect those contracts to be assigned to us, such consent has not yet been obtained. Excluding these customers, CBI represented 3% of our annualized rent as of September 30, 2012. As of September 30, 2012, no single other customer represented more than 8% of our annualized rent, and our top 10 customers (including CBI) represented 46% of our annualized rent.

Strategically Located Portfolio. Our portfolio is located in several domestic and international markets possessing attractive characteristics for enterprise-focused data center operations. We have domestic properties in five of the top 10 largest U.S. cities by population (Chicago, Dallas, Houston, Phoenix and San Antonio), according to the U.S. Census Bureau, and four of the top 10 cities for Fortune 500 headquarters (Chicago, Cincinnati, Dallas and Houston), according to Forbes. We believe cities with large populations or a large number of corporate headquarters are likely to produce incremental demand for IT infrastructure. In addition, being located close to our current and potential customers provides chief information officers (“CIOs”) with additional confidence when outsourcing their data center infrastructure.

Modern, High Quality Facilities. Our portfolio includes highly efficient, reliable facilities with advanced cooling capabilities and the security systems necessary to provide an environment suitable for some of our clients’ most vital technology infrastructure. In our newest facilities, we take a “Massively Modular^SM” approach to site selection, design and construction such that we are able to deliver a range of power densities to our customers within a single facility. Our Massively Modular^SM design principles allow us to efficiently stage construction on a large scale and deliver CSF in a timeframe that we believe is one of the best in the industry. We acquire or build a large powered shell capable of scaling with our customers’ power and colocation space needs. The powered shell can be acquired or constructed for a relatively inexpensive capital cost. Once the building shell is ready, we can build individual data center halls in portions of the building space to meet the needs of customers on a modular basis. This modular data center hall construction can be completed in approximately 16 weeks to meet our customers’ immediate needs. This short construction timeframe ensures a very high utilization of the assets and minimizes the time between our capital investment and the receipt of customer revenue, favorably impacting our return on investment while also translating into lower costs for our customers. Our design principles also allow us to add incremental equipment to increase power densities as our customers’ power needs increase, which provides our customers with a significant amount of flexibility to manage their IT demands. We believe this Massively Modular^SM approach allows us to respond to rapidly evolving customer needs, to commit capital toward the highest return projects and to develop state-of-the-art data center facilities.

Significant Leasing Capability and Low Recurring Rent Churn. Our focus on the customer, our ability to scale with its needs, and our operational excellence provides us with two key benefits: embedded future growth from our customer base and low recurring rent churn. Our total annualized rent increased by approximately 22%, and our existing customer base provided approximately 72% of such increase, between October 1, 2011 and September 30, 2012. Since October 1, 2011, we have increased NRSF by 19%, while maintaining a high percentage of NRSF leased of 79% at September 30, 2012.

Our management team focuses on minimizing recurring rent churn. We define recurring rent churn as any reduction in recurring rent due to customer terminations, net pricing reductions or service reductions as a percentage of the annualized rent at the beginning of the applicable period, excluding any impact from metered power reimbursements. In 2011, we experienced a recurring rent churn of 3%, approximately half of which was attributable to customers that ceased using our facilities. For the nine months ended September 30, 2012, our recurring rent churn was 4.0% (5.3% annualized), which includes the termination of one lease for legacy data center space that had been utilized for over 20 years. The legacy data center space has been decommissioned and is expected to be developed into data center space that we believe will generate higher amounts of revenue than the prior lease. Excluding this lease, the recurring rent churn for the nine months ended September 30, 2012 would have been 2.9% (3.9% annualized).

Significant, Attractive Expansion Opportunities. Our current development properties and available acreage were selected based on extensive site selection criteria and the collective industry knowledge and experience of our management team. As a result, we believe that our development portfolio contains properties that are located in markets with attractive supply and demand conditions and that possess suitable physical characteristics to support data center infrastructure. In addition to our operating NRSF of approximately 1,630,000 as of September 30, 2012, we are currently developing vacant properties and new facilities to create approximately 379,000 NRSF across three distinct markets. As of September 30, 2012, we also have 762,000 NRSF of powered shell available for future development, and we own approximately 146 acres of land that are available for future data center facility development.

Differentiated Reputation for Service. We believe that the decision CIOs make to outsource their data center infrastructure has material implications for their businesses, and, as such, CIOs look to third-party data center providers that have a reputation for serving similar organizations and that are able to deliver a customized solution. We take a consultative approach to understanding the unique requirements of our customers, and our

design principles allow us to deliver robust flexibility in the scale, power and location of our data center infrastructure. We believe that this approach has helped fuel our growth. Our current customers are also often the source of new contracts, with referrals being an important source of new customers.

Experienced Management Team. Our management team is comprised of individuals drawing on diverse knowledge and skill sets acquired through extensive experiences in the real estate, telecommunications and mission-critical infrastructure industries. In aggregate, our management team of nine individuals has an average of approximately 15 years of experience in the data center and communications industries.

Business and Growth Strategies

Our objective is to grow our revenue and earnings and maximize stockholder returns by continuing to expand our data center infrastructure outsourcing business.

Increasing Revenue from Existing Customers and Properties. We have historically generated a significant portion of our revenue growth from our existing customers. Our total annualized rent increased by approximately 22%, and our existing customer base provided approximately 72% of such increase, between October 1, 2011 and September 30, 2012. We plan to continue to target our existing customers, because we believe that many have significant data center infrastructure that has not yet been outsourced, and many will require additional data center space to support their growth and their increasing reliance on technology infrastructure in their operations. To address new demand, as of September 30, 2012, we have approximately 337,000 NRSF available for lease, 379,000 NRSF under development and 762,000 NRSF of additional powered shell available for future development. Our portfolio also contains approximately 146 acres of land that are available for future data center facility development.

Attracting and Retaining New Customers. According to a recent IDC survey, less than 10% of large U.S. enterprises use third-party data center colocation services. Increasingly, enterprises are beginning to recognize the complexities of managing data center infrastructure in the midst of rapid technological development and innovation. We believe that these complexities, brought about by the rapidly increasing levels of Internet traffic and data, obsolete existing corporate data center infrastructure, increased power and cooling requirements and increased regulatory requirements, are driving the need for companies to outsource their data center facility requirements. Consequently, this will significantly increase the percentage of companies that use third-party data center colocation services over the next several years. We believe that our high quality assets and reputation for serving large enterprises have been, and will be, key differentiators for us in attracting customers that are outsourcing their data center infrastructure needs. Since 2010, we have signed more than 100 new customers, many of whom were outsourcing data center infrastructure for the first time. We plan to continue to pursue large enterprise customers by leveraging our relationships and reputation, and by developing our existing pipeline of inventory to meet their needs.

Expanding into New Domestic and International Markets. Our expansion strategy focuses on developing new data centers in markets where our customers are located and in markets where our customers want to be located. We regularly meet with our customers to understand their business strategies and potential data center needs. We also conduct extensive analysis to ensure an identified market displays strong data center fundamentals, independent of the demand presented by any particular customer. We believe that this approach significantly reduces the risk associated with expansion into new markets because it provides strong visibility into our anticipated cash flow and helps to ensure targeted returns on new developments. Our strategy for entering a new market will vary based on in-place real estate and data center infrastructure and could include greenfield construction projects as well as acquisitions.

Growing Interconnection Business. Our customers are increasingly seeking to connect to one another via private peering, cross connects and/or public switching environments. The demand for interconnection creates additional rental and revenue growth opportunities for us, and we believe that customer interconnections increase our likelihood of customer retention by providing an environment not easily replicated by competitors.

Selectively Pursuing Property Acquisition Opportunities. We intend to seek opportunities to acquire existing or potential data center properties in key strategic markets. In addition, we currently lease certain of our data center properties and, to the extent economically attractive, we may opportunistically seek to purchase those properties.

Our principal executive offices are located at 1649 West Frankford Rd, Carrollton, TX 75007. Our telephone number is (972) 350-0060.

Recent Developments

We commissioned the 36,000 CSF under development at our South Ellis Street (Phoenix) facility in the fourth quarter of 2012, bringing our data center capacity to 932,000 CSF as of December 31, 2012, an increase of 22% as compared to December 31, 2011. During the fourth quarter of 2012, we signed leases for approximately 40,000 CSF, our highest sales quarter in 2012. Approximately 16,000 CSF sold during the fourth quarter of 2012 was in our Westover Hills Blvd (San Antonio) facility. Our Westover Hills Blvd (San Antonio) facility was commissioned in the third quarter of 2012 and is now approximately 60% sold to customers. In our Kestral Way (London) facility, we sold approximately 2,000 CSF of our existing space, and construction commenced on an additional 5,000 CSF, which is expected to be completed in the first quarter of 2013. This entire expansion of 5,000 CSF was leased to a customer in the fourth quarter of 2012.

Approximately 90% of the signed leases in the fourth quarter, including all of the Westover Hills Blvd (San Antonio) leases, did not commence billing in 2012 but are expected to commence billing during the first half of 2013. Therefore, our percent leased was 76% as of December 31, 2012 due to the additional CSF commissioned at the South Ellis Street (Phoenix) facility and the commissioning of 30,000 NRSF of office and other space at our Frankford Rd (Carrollton) facility during the fourth quarter of 2012. Adjusting for the leases sold in the fourth quarter but excluding the lease for the unfinished expansion for our Kestral Way (London) facility, our utilization was approximately 78% as of December 31, 2012, consistent with our utilization as of September 30, 2012.

Summary Risk Factors

Investment in our common stock involves risks. You should carefully consider the following important risks as well as the additional risks described in “Risk Factors”:

Structure and Formation of Our Company

On November 20, 2012, we closed the formation transactions, which were designed to consolidate the ownership of a portfolio of properties owned by CBI into our operating partnership, facilitate this offering, enable us to raise necessary capital to repay indebtedness owed to CBI and enable us to qualify as a REIT for U.S. federal income tax purposes commencing with our taxable year ending December 31, 2013. Pursuant to the formation transactions and in conjunction with this offering:

Upon completion of this offering:

All the properties and other interests transferred to CyrusOne LP were contributed by wholly-owned subsidiaries of CBI. Because both CyrusOne LP and the certain subsidiaries of CBI that contributed the properties comprising our portfolio (the “Contributors”) will be under the common control of CBI until the completion of this offering and were under common control at the time of the formation transactions, the transfer of assets and liabilities of each of these entities will be accounted for at historical cost in a manner similar to a pooling of interests.

Our Structure

The following diagram depicts our ownership structure upon completion of this offering.

Restrictions on Transfer

Under the partnership agreement of our operating partnership, except under certain circumstances, unit holders do not have redemption or exchange rights for a period of 12 months and may not otherwise transfer their operating partnership units for a period of 12 months following completion of this offering. In addition, we, our operating partnership, CBI and our executive officers and directors have agreed not to sell or otherwise transfer or encumber any shares of our common stock or securities convertible or exchangeable into our common stock (including operating partnership units) owned by them at the completion of this offering or thereafter acquired by them for a period of 12 months, with respect to CBI, and 180 days, with respect to us and our executive officers and directors, after the completion of this offering without the consent of Morgan Stanley & Co. LLC and Merrill Lynch, Pierce, Fenner & Smith Incorporated, subject, in each case, to certain exceptions.

Conflicts of Interest

Following the completion of this offering, there will be conflicts of interest with respect to certain transactions between the unitholders in our operating partnership, including CBI, on the one hand, and us and our stockholders, on the other. See “Risk Factors—Risks Related to Our Organizational Structure.”

On November 20, 2012, CBI contributed its ownership interests in certain properties and in other assets and liabilities to our operating partnership in the formation transactions. Under the agreements relating to the contribution of such interests, we have contractual rights to indemnification in the event of breaches of representations or warranties made by CBI. None of these agreements were negotiated on an arm’s length basis. See “Certain Relationships and Related Transactions—Contribution Agreements.”

Our Chairman is the President and Chief Executive Officer and a director of CBI. In addition, some of our directors and executive officers own a substantial amount of CBI common stock, options and other instruments, the value of which is related to the value of common stock of CBI. The direct and indirect interests of our directors and executive officers in common stock of CBI, and us, could create, or appear to create, conflicts of interest with respect to decisions involving both CBI and us that could have different implications for CBI than they do for us.

We have granted CBI a waiver of the ownership restrictions contained in our charter, subject to certain initial and ongoing conditions designed to protect our status as a REIT, including the receipt of an Internal Revenue Service (“IRS”) private letter ruling or an opinion of counsel from a nationally recognized law firm that the exercise of any such exemption should not cause any rent payable by CBI to jeopardize our REIT status.

We lease colocation space in our data centers to Cincinnati Bell Telephone Company LLC, a subsidiary of CBI (“CBT”), and CBTS. Prior to this offering, we entered into separate data center colocation agreements with CBT and CBTS whereby we will continue to lease colocation space to each of them at certain of our data centers. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

Prior to this offering, we purchased the property located at 229 West Seventh Street, which is included under “—CyrusOne Inc.—Our Portfolio” as one of our 23 operating facilities and which we had formerly leased from CBT. In connection with this purchase, we also executed a reciprocal easement and shared services agreement and a right of first opportunity and refusal agreement with CBT. Pursuant to the reciprocal easement and shared services agreement, we granted reciprocal easements to each other; CBT has easements for continued use of portions of our building and CBT provides fuel storage, fire suppression and other building services to us; and we provide chilled water, building automation systems related to heating, ventilation and air conditioning (“HVAC”) and other building services to CBT. Pursuant to the right of first opportunity and refusal agreement, we and CBT have agreed to grant to each other rights of first opportunity and first refusal to purchase each other

party’s property in the event that either party desires to sell its property to a non-affiliate third party. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

In addition, CBT occupies space in our 229 West Seventh Street facility that is utilized in its network operations. In connection with our purchase of this property, we entered into an agreement to lease this space to CBT for a period of five years, with three renewal options of five years each. Prior to this offering, we also entered into an agreement to lease space at CBT’s 209 West Seventh Street facility for a period of five years, with three renewal options of five years each. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

CBI provides various management services, including executive management, cash management, legal, treasury, human resources, accounting, tax, internal audit and risk management services. Prior to this offering, we entered into a transition services agreement with CBI, pursuant to which CBI will provide certain of these services, on an as needed basis, to our operating partnership. See “Certain Relationships and Related Transactions—Transition Services Agreements.”

Effective January 1, 2012, the Predecessor entered into a transition services agreement with CBTS pursuant to which each party agreed to provide certain services to the other party. Services provided by CBTS to the Predecessor included network support, service calls, monitoring and management, storage and backup and IT systems support. Services provided by the Predecessor to CBTS included data center colocation and network interface charges for a fiber network. Prior to this offering, we replaced this transition services agreement with a new transition services arrangement with CBTS pursuant to which each party will provide certain services to the other party. Services provided by CBTS to us include migration and support services for hardware and applications used for local telephony and IT services by our employees, as well as back office billing transition support for customers that have not yet been transitioned off of the CBTS billing platform. Services provided by us to CBTS consist of network interface charges. See “Certain Relationships and Related Transactions—Transition Services Agreements.”

Also effective January 1, 2012, the Predecessor entered into marketing agreements with CBT and CBTS to appoint these affiliates as CyrusOne’s authorized marketing representatives. Pursuant to the terms of these agreements, the Predecessor pays these affiliates a commission for all new leases for space they attain, which is calculated as a percentage of the first month’s recurring revenue with respect to such space. The term of these agreements expired on December 31, 2012. See “Certain Relationships and Related Transactions—Marketing Agreement.”

We have also entered into services agreements with CBT and CBTS. Under the CBTS services agreement, CBTS has agreed to provide us with certain managed storage and backup services. These services will be provided on a month-to-month basis, and charges will be based on the variable amount of gigabytes managed by CBTS each month. Under the CBT services agreement, CBT provides us with connectivity services related to several of our data center facilities. These services are related to the use of fiber and circuit assets that are currently a part of the CBI network. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

Prior to this offering, we entered into agreements to lease office space to CBT at our Goldcoast Drive (Goldcoast) data center facility and to CBTS at our Parkway (Mason) data center facility. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

As of September 30, 2012, certain of the Predecessor’s leases had not yet been assigned to CyrusOne. CBTS is the lessor named in these contracts. In 2012, we entered into an agreement with CBTS whereby we perform all obligations of CBTS under the lease agreements, CBTS confers to us the benefits received under such lease agreements and CBTS is granted sufficient usage rights in each of our data centers so that it remains as lessor

under each such lease agreement until the lease can be assigned to us. In addition, CBTS will continue to perform billing and collections on these accounts until the assignment has been completed. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

On November 20, 2012, we also entered into a non-competition agreement with CBI, pursuant to which we and CBI have agreed not to enter into each other’s lines of business, subject to certain exceptions, for a period of four years from such date. See “Certain Relationships and Related Transactions—Other Benefits to Related Parties and Related Party Transactions.”

Under the partnership agreement of our operating partnership, the limited partners of our operating partnership will expressly agree that the general partner of our operating partnership is acting for the benefit of the operating partnership, the limited partners of our operating partnership and our stockholders, collectively. The general partner is under no obligation to give priority to the separate interests of the limited partners in deciding whether to cause our operating partnership to take or decline to take any actions. If there is a conflict between the interests of us or our stockholders, on the one hand, and the interests of the limited partners of our operating partnership, on the other, the partnership agreement of our operating partnership provides that any action or failure to act by the general partner that gives priority to the separate interests of us or our stockholders that does not result in a violation of the contractual rights of the limited partners of our operating partnership under the partnership agreement will not violate the duties that the general partner owes to our operating partnership and its partners.

Affiliates of one or more of our underwriters participated as agents or lenders under the revolving credit facility that we entered into with a syndicate of financial institutions. These transactions create potential conflicts of interest because the underwriters have an interest in the successful completion of this offering beyond the underwriting discounts and commissions and financial advisory fees they will receive.

Restrictions on Ownership and Transfer of Our Stock

Due to limitations on the concentration of ownership of REIT stock imposed by the Internal Revenue Code of 1986, as amended (the “Code”), among other purposes, our charter provides for restrictions on ownership and transfer of our shares of stock, including, in general, prohibitions on any person actually or constructively owning more than 9.8% in value or number (whichever is more restrictive) of the outstanding shares of our common stock or 9.8% in value of the outstanding shares of all classes or series of our stock. Our charter, however, permits exceptions to be made for stockholders provided that our board of directors determines such exceptions will not jeopardize our tax status as a REIT. Our board of directors has granted CBI exemptions from the ownership limits applicable to other holders of our common stock, subject to certain initial and ongoing conditions designed to protect our status as a REIT, including the receipt of an IRS private letter ruling or an opinion of counsel from a nationally recognized law firm that the exercise of any such exemption should not cause any rent payable by CBI to jeopardize our REIT status.

Related Financings

Senior Notes Issuance

On November 20, 2012, our operating partnership issued $525 million of senior notes, from which the net proceeds were approximately $512 million. Our operating partnership used a portion of the net proceeds from the senior notes issuance to repay approximately $480 million of indebtedness owed to CBI. The indenture governing the senior notes contains covenants that restrict our ability to engage in certain activities such as incurring certain additional indebtedness and making certain investments. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Material Provisions of Consolidated Indebtedness to be Outstanding After this Offering.”

Revolving Credit Facility

On November 20, 2012, we entered into a $225 million revolving credit facility with a syndicate of financial institutions. Affiliates of several of the underwriters are lenders under this facility. The revolving credit facility is guaranteed by CyrusOne and CyrusOne GP, as well as certain of our operating partnership’s existing and future wholly-owned domestic subsidiaries, subject to certain exceptions. All obligations under the revolving credit facility, and the guarantees of those obligations, are secured by substantially all of our assets, subject to certain exceptions. We intend to use the revolving credit facility, among other things, to finance the acquisition of properties, provide funds for customer improvements and capital expenditures and provide for working capital and for other corporate purposes. The revolving credit facility contains customary covenants for credit facilities of this type. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Material Terms of Our Indebtedness to be Outstanding After this Offering.”

Upon completion of this offering, we expect to have liquidity of approximately $520 million based on our estimated cash balance and availability under the revolving credit facility.

This Offering

Distribution Policy

We intend to make regular quarterly distributions to holders of our common stock. We intend to make a pro rata initial distribution with respect to the period commencing on the completion of this offering and ending March 31, 2013, based on $0.16 per share for a full quarter. On an annualized basis, this would be $0.64 per share, or an annual distribution rate of approximately 3.4% based on the initial public offering price of $19.00 per share. We estimate that this initial annual distribution rate will represent approximately 68.5% of estimated cash available for distribution for the 12 months ending September 30, 2013. We established this intended initial annual distribution rate based on our estimate of cash available for distribution for the 12 months ending September 30, 2013, which we have calculated based on adjustments to our pro forma loss before noncontrolling interests for the 12 months ended September 30, 2012. We intend to maintain our initial distribution rate for the 12-month period following completion of this offering unless actual results of operations, economic conditions or other factors differ materially from the assumptions used in our estimate. Distributions made by us will be authorized and determined by our board of directors in its sole discretion out of funds legally available therefor and will be dependent upon a number of factors, including restrictions under applicable law and other factors described under “Distribution Policy.” We believe that our estimate of cash available for distribution constitutes a reasonable basis for setting the initial distribution rate; however, we cannot assure you that the estimate will prove accurate, and actual distributions may therefore be significantly different from the expected distributions. If we have underestimated our cash available for distribution, we may need to increase our borrowings in order to fund our intended distributions. We expect that, at least initially, our distributions may exceed our net income under accounting principles generally accepted in the United States of America (“U.S. GAAP”) because of non-cash expenses included in net income. We do not intend to reduce the expected distributions per share if the underwriters exercise their over-allotment option.

Our Tax Status

We intend to elect and qualify as a REIT for U.S. federal income tax purposes commencing with our taxable year ending December 31, 2013. Our qualification as a REIT depends upon our ability to meet on a continuing basis, through actual investment and operating results, various complex requirements under the Code, relating to, among other things, the sources of our gross income, the composition and values of our assets, our distribution levels and the diversity of ownership of our shares. We believe that we have been organized in conformity with the requirements for qualification and taxation as a REIT under the Code and that our intended manner of operation will enable us to meet the requirements for qualification and taxation as a REIT.

We have received a private letter ruling from the IRS, subject to the terms and conditions contained therein, with respect to certain issues relevant to our qualification as a REIT. Although we may generally rely upon the ruling, no assurance can be given that the IRS will not challenge our qualification as a REIT on the basis of other issues or facts outside the scope of the ruling.

So long as we qualify as a REIT, we generally will not be subject to U.S. federal income tax on our net taxable income that we distribute currently to our stockholders. If we fail to qualify as a REIT in any taxable year and do not qualify for certain statutory relief provisions, we would be subject to U.S. federal income tax at regular corporate rates and would be precluded from re-electing to be taxed as a REIT for the subsequent four taxable years following the year during which we lost our REIT qualification. Even if we qualify for taxation as a REIT, we may be subject to certain U.S. federal, state and local taxes on our income or property, and the income of our taxable REIT subsidiaries (each, a “TRS”) will be subject to taxation at regular corporate rates.

Summary Financial Data

The following table sets forth summary financial and other data for the Predecessor (as described below) on both a historical and pro forma basis. We have not presented historical information for the newly-formed registrant, CyrusOne, because it has not had any corporate or business activity since its formation other than the incurrence of costs to support this offering, the formation transactions, the related financing transactions and the issuance of shares of common stock in connection with the initial capitalization of the company and because we believe that a discussion of the results of this newly-formed registrant would not be meaningful. For more information regarding the formation transactions, please see “Structure and Formation of Our Company.”

We use the term “Predecessor” to mean the historical data center activities and holdings of CBI. CBI has operated its Cincinnati-based data center business for over 10 years; in addition, it acquired GramTel, a data center operator in South Bend, Indiana and Chicago, Illinois, for approximately $20 million in December 2007; and it acquired Cyrus Networks, a data center operator based in Texas, for approximately $526 million, net of cash acquired, in June 2010. As part of the formation transactions, certain subsidiaries of CBI contributed these assets and operations to our operating partnership, CyrusOne LP.

The summary historical financial information as of December 31, 2011 and 2010 and for each of the years ended December 31, 2011, 2010 and 2009 has been derived from the Predecessor’s audited combined financial statements included elsewhere in this prospectus. The summary historical financial information as of September 30, 2012 and for the nine months ended September 30, 2012 and 2011 has been derived from the Predecessor’s unaudited condensed combined financial statements included elsewhere in this prospectus. In the opinion of management, the unaudited interim financial information included herein includes all adjustments (consisting of only normal recurring adjustments) necessary to present fairly the information set forth herein. The results of operations for the interim period ended September 30, 2012 are not necessarily indicative of the results to be obtained for the full fiscal year.

The unaudited pro forma condensed combined financial data as of and for the nine months ended September 30, 2012 and for the year ended December 31, 2011, is derived from CyrusOne’s and the Predecessor’s combined pro forma financial statements which appear elsewhere in this prospectus. This pro forma data has been presented as if this offering, the formation transactions and the related financing transactions had all occurred: (i) on September 30, 2012 for the pro forma condensed combined balance sheet data and (ii) as of January 1, 2011 for the pro forma condensed combined statement of operations data. The pro forma financial data is not necessarily indicative of what our actual financial position and results of operations would have been as of the date and for the periods indicated, nor does it purport to represent our future financial position or results of operations.

You should read the following summary financial data of the Predecessor in conjunction with our combined historical financial statements and the related notes and with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” which are included elsewhere in this prospectus.

We calculate funds from operations, as adjusted (“FFO As Adjusted”) as FFO plus amortization and impairments of customer relationship intangibles. Because the value of such customer relationship intangibles is inextricably connected to the real estate acquired, we believe the amortization and impairments of such intangibles is analogous to real estate depreciation and impairments; and therefore, we add the customer relationship intangible amortization and impairments back to FFO As Adjusted for similar treatment with real estate depreciation and impairments. We believe our FFO As Adjusted calculation provides a more comparable measure to others in the industry. Our customer relationship intangibles are primarily associated with the acquisition of Cyrus Networks and represented 22% of the value of the assets acquired.

Management uses FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted as supplemental performance measures because they provide performance measures that, when compared year over year, capture trends in occupancy rates, rental rates and operating costs. We also believe that, as widely recognized measures of the performance of REITs, FFO and pro forma FFO will be used by investors as a basis to compare our operating performance with that of other REITs.

However, because FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted exclude real estate depreciation and amortization and real estate impairments (and, in the case of FFO As Adjusted and pro forma FFO As Adjusted, exclude amortization and impairments of customer relationship intangibles) and capture neither the changes in the value of our properties that result from use or from market conditions, nor the level of capital expenditures and leasing commissions necessary to maintain the operating performance of our properties, all of which have real economic effect and could materially impact our results from operations, the utility of FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted as measures of our performance is limited. Other REITs may not calculate FFO or pro forma FFO in accordance with the NAREIT definition or may not calculate FFO As Adjusted or pro forma FFO As Adjusted in the same manner. Accordingly, our FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted may not be comparable to others. Therefore, FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted should be considered only as supplements to net income as measures of our performance. FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted should not be used as measures of our liquidity nor as indicative of funds available to fund our cash needs, including our ability to make distributions. FFO, pro forma FFO, FFO As Adjusted and pro forma FFO As Adjusted also should not be used as supplements to or substitutes for cash flow from operating activities computed in accordance with U.S. GAAP.

A reconciliation of net (loss) income to FFO and FFO As Adjusted is presented below: