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As filed with the Securities and Exchange Commission on September 14, 2007

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

EQUINIX, INC.

(Exact Name of Registrant as Specified in Its Charter)

301 Velocity Way, Fifth Floor

Foster City, CA 94404

(650) 513-7000

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Brandi Galvin Morandi

General Counsel and Assistant Secretary

Equinix, Inc.

301 Velocity Way, Fifth Floor

Foster City, CA 94404

(650) 513-7000

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

The Commission is requested to send copies of all communications to:

Approximate date of commencement of proposed sale to the public:  From time to time after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ¨

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  x

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ¨

CALCULATION OF REGISTRATION FEE

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The information in this prospectus is not complete and may be changed. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED SEPTEMBER 14, 2007

3,662,556 Shares

Common Stock

We are offering 3,662,556 shares of our common stock. We have granted the underwriters an option to purchase up to 549,383 additional shares of our common stock from us to cover over-allotments, if any.

Concurrently with this offering, we are offering $300,000,000 aggregate principal amount of             % Convertible Subordinated Notes due 2014 (or a total of $345,000,000 aggregate principal amount of notes if the underwriters exercise their over-allotment option in full) pursuant to a separate registration statement and prospectus. Those notes are not being offered by this prospectus. See “The Concurrent Offering.”

Our common stock is listed on the NASDAQ Global Select Market under the symbol “EQIX.” The last reported sale price of our common stock on September 13, 2007 was $81.91 per share.

Investing in our common stock involves risks. See “ Risk Factors” beginning on page 8.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares to purchasers on or about September     , 2007.

Jefferies & Company

UBS Investment Bank

September     , 2007

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ABOUT THIS PROSPECTUS

This prospectus incorporates important business and financial information about us and our subsidiaries, including our recently acquired subsidiary, IXEurope plc, that is not included in or delivered with this prospectus. Information incorporated by reference is available without charge to prospective investors upon written request to us at 301 Velocity Way, Fifth Floor, Foster City, California 94404, Attention: Investor Relations, or by telephone at (650) 513-7000.

You should rely only on the information contained or incorporated by reference in this prospectus or in any related free writing prospectus. Neither we nor the underwriters have authorized any other person to provide you with different or additional information. If anyone provides you with different or additional information, you should not rely on it. We are not, and the underwriters are not, making an offer or sale of securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information in this prospectus is accurate as of the date appearing on the front cover of this prospectus only. Our business, financial condition, results of operations and prospects may have changed since that date.

We have not taken any action to permit an offering of our common stock outside the United States or to permit the possession or distribution of this prospectus outside the United States. Persons outside the United States who come into possession of this prospectus must inform themselves about and observe any restrictions relating to the offering of our common stock and the distribution of this prospectus outside of the United States.

You must comply with all applicable laws and regulations in force in any applicable jurisdiction and you must obtain any consent, approval or permission required by you for the purchase, offer or sale of our common stock under the laws and regulations in force in the jurisdiction to which you are subject or in which you make your purchase, offer or sale, and neither we nor the underwriters will have any responsibility therefor.

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We reserve the right to withdraw this offering of our common stock at any time. We and the underwriters also reserve the right to reject any offer to purchase, in whole or in part, for any reason, or to sell less than the amount of our common stock offered hereby.

Certain persons participating in this offering may engage in transactions that stabilize, maintain or otherwise affect the price of our common stock. Such transactions may include stabilization and the purchase of our common stock to cover short positions. For a description of these activities, see “Underwriting.”

Unless expressly stated or the context otherwise requires, the terms “we,” “our,” “us,” “the company” and “Equinix” refer to Equinix, Inc., a Delaware corporation, and its consolidated subsidiaries.

FORWARD-LOOKING STATEMENTS

This prospectus, including the documents incorporated by reference herein, contains forward-looking statements that involve risks and uncertainties. Statements contained in this prospectus or incorporated by reference herein that are not purely historical are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, including statements regarding Equinix’s financial outlook, competitive position, business strategies, expectations, beliefs, intentions or other strategies regarding the future. All forward-looking statements included in this document are based on information available to Equinix on the date hereof, and Equinix assumes no obligation to update any such forward-looking statements. Equinix’s actual results could differ materially from those anticipated in these forward-looking statements as a result of certain factors, including, but not limited to, those set forth in this prospectus under “Risk Factors.” You should carefully consider the risks described in the “Risk Factors” section, in addition to the other information set forth in this prospectus and incorporated by reference herein, before making an investment decision.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act relating to the common stock offered by this prospectus. This prospectus is a part of that registration statement, which includes additional information not contained in this prospectus.

We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC (including exhibits to such documents) at the SEC’s Public Reference Room at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the Public Reference Room. Our SEC filings are also available to the public at the SEC’s website at www.sec.gov.

INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below (except the information contained in such documents to the extent “furnished” and not “filed”) and any future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934:

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Please refer to our Form 8-K filed on September 14, 2007 for the following information relating to IXEurope:

You may request, and we will provide you with, a copy of these filings, at no cost, by calling us at (650) 513-7000 or by writing to us at the following address:

Equinix, Inc.

301 Velocity Way, Fifth Floor

Foster City, CA 94404

Attn: Investor Relations

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SUMMARY

This summary highlights the information contained or incorporated by reference in this prospectus. Because this is only a summary, it does not contain all of the information that may be important to you. For a more complete understanding of our business and financial affairs, we encourage you to read this entire prospectus, including “Risk Factors,” together with the documents incorporated by reference into this prospectus, which include historical and pro forma financial statements of us and IXEurope and the notes to those financial statements, before making a decision whether to invest in our common stock.

Unless expressly provided, the information contained in this prospectus assumes that the underwriters’ over-allotment option is not exercised.

Overview

Equinix provides network neutral colocation, interconnection and managed services to enterprises, content companies, systems integrators and the world’s largest network providers. Through our 35 Internet Business Exchange hubs, or IBX hubs, in 17 markets in the United States, Europe and the Asia-Pacific region, customers can locate their mission critical infrastructure and directly interconnect with each other for critical traffic exchange requirements. Customers choose Equinix for service reliability and the ability to access multiple networks in one location. Direct interconnection to over 200 networks, which serve more than 90% of the world’s Internet routes, enables our customers to increase performance while significantly reducing costs. Based on our network neutral model and the quality of our IBX hubs, we believe we have established a critical mass of customers. We believe that this critical mass and the resulting “network effect,” combined with a strong financial position, will continue to drive new customer growth and bookings. In addition to our business momentum, significant increases in overall customer demand combined with reduced supply in the data center market has resulted in strong market growth and pricing power. As a result of our largely fixed cost model, any growth in revenue from our current IBX hubs would likely drive incremental margins and increased operating cash flow.

Our network neutral business model is a key differentiator for us when compared to other large providers of colocation services. Because we do not operate a network, we are able to offer our customers direct interconnection to the largest aggregation of bandwidth providers and Internet service providers. The world’s top tier Internet service providers, numerous access networks, second tier providers and international carriers, such as AOL, at&t, British Telecom, Cable & Wireless, Comcast, Deutsche Telekom, Level 3, NTT, Qwest, SingTel, Sprint and Verizon, are all currently located at our IBX hubs. Access to such a wide variety of networks has attracted nine of the top 10 Internet properties and numerous other enterprise and government customers, including Amazon.com, Bank of America, Capgemini, Citibank, Deutsche Borse Systems, Electronic Arts, Fox Interactive Media, Fujitsu Asia, Goldman Sachs, Google, IBM, McGraw Hill, Merrill Lynch, MSN, NASA, News Corporation, Salesforce.com, Sony, UBS and Yahoo!.

Our services are primarily comprised of colocation, interconnection and managed IT infrastructure services.

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The colocation markets across the world have developed differently. In the United States and Asia-Pacific regions, the market for our services has historically been served by large telecommunications carriers who have bundled their telecommunications services and managed services with their colocation offerings. Over the past several years, a number of these telecommunications carriers have eliminated or reduced their colocation footprint to focus on their core businesses. Additionally, many of the competitive providers have failed to scale their businesses and have been forced to exit the market. In Europe, the market has been served by a variety of providers including traditional large telecommunications carriers as well as several network-neutral players of varying size and scale. In each of these regions, we successfully differentiate our service offerings based on our service reliability and access to multiple networks.

Equinix addresses a specific customer segment in the market, namely, those enterprise, content or network companies that need to outsource their critical infrastructure and/or to directly interconnect to multiple parties. There now exists a significant supply and demand imbalance in the customer segment we serve due to the departure or consolidation of several key players from this market, a decline in usable capacity in legacy centers which cannot adequately address the significant power needs of today’s customers and a lack of new centers being built. We are focused on a valuable segment of customers who require smaller footprints and value direct interconnection. For example, although some of our larger content customers, including companies such as AOL, Google and MSN operate or are building their own data centers for their large infrastructure deployments or install large footprints in centers being built by real estate investment trusts (REITs), these customers also continue to have a presence in an Equinix data center to use our interconnection services to reach their business partners. The overall reduction in supply in the industry has led to increased pricing and accelerated demand for our centers. Although our growth is primarily driven by existing customers, we have gained many of those customers no longer served by the traditional network-based colocation providers as access to those providers’ networks is also available in our IBX hubs. Strategically, we will continue to look at attractive opportunities to grow our market share and selectively improve our footprint and service offerings.

Our Strategy

Our objective is to become the premier hub for enterprises, content providers and government agencies to locate their information technology infrastructure operations in order to gain maximum benefits from the choice of networks and partners in the most simple and efficient manner. Key components of our strategy include the following:

Expand to Satisfy our Customers’ Growth Needs.    Our growth is primarily driven by our existing customer base ordering new services and we plan to continue to expand in key markets based on customer demand. We currently have significant expansions underway in 11 of our 17 markets across the world. As a part of our overall expansion strategy, in September 2007, we expanded into the European market with our acquisition of IXEurope plc, a leading provider of colocation services serving 450 customers in four major markets across Europe. Our global expansion strategy is to continue to grow in select existing markets and possibly expand to additional markets based on anticipated customer demand and financial return. We conduct extensive demand studies, property due diligence and financing analysis designed to examine and optimize the mix of variables in our expansion decisions. We expect to execute this expansion strategy in a cost-effective and prudent manner through a combination of acquiring existing centers through lease or purchase, or building new centers based on key criteria, such as demand and potential financial return, in each market.

Continue to Build upon our Critical Mass of Network Providers and Content Companies and Leverage the Network Effect.    We have assembled a critical mass of premier network providers and content companies and have become one of the core hubs of the Internet. This critical mass is a key selling point since content

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companies want to connect with a diverse set of networks to provide the best connectivity to their end-customers and network companies want to sell bandwidth to content customers and interconnect with other networks in the most efficient manner available. As networks, content providers and enterprises locate in our IBX centers, it benefits their suppliers and business partners to do so as well to gain the full economic and performance benefits of direct interconnection. These partners, in turn, pull in their business partners, creating a “network effect” of customer adoption.

Grow our Enterprise Business.    Our customers include several large enterprises including key players in the enterprise sector, such as Bank of America, Capgemini, Citibank, Deutsche Borse Systems, Goldman Sachs, IBM, McGraw Hill, Merrill Lynch, Salesforce.com, Sony, UBS and others. Because of our unique model of direct interconnection, we have attracted a number of large enterprises who require access to multiple networks for their web-enabled applications or to access their business partners. One example is the Financial Exchange service that we offer in IBX centers globally. This service allows financial institutions, such as the Chicago Mercantile Exchange, Deutsche Borse Systems and many others the ability to directly interconnect with networks and financial trading partners to virtually eliminate delay in electronic trading environments. We expect to expand to other enterprise segments including digital media and others and drive growth into 2008.

Promote our IBX Centers as the Highest Performance Data Centers Available.    We believe that data center reliability, power availability and network choice are the most important attributes when our customers are choosing a data center provider. Our IBX hubs are next-generation data centers and offer customers advanced security, reliability and redundancy. For example, our security design in the U.S. IBX centers includes five levels of biometrics security to access customer cages and our power infrastructure includes N+1 redundancy for all systems and has delivered 99.9999% uptime over the period from January 1, 2002 through June 30, 2007. In Europe, our centers are ISO 9000:2001 certified. Our global support staff, trained to aid customers with operational support, is available 24 hours a day, 365 days a year. We intend to continue to invest in maintenance and energy efficiency initiatives and customer service support to ensure that we can continue to provide market leading service reliability.

Provide New Products and Services within our IBX Centers.    We plan to continue to offer additional products and services that are consistent with our business focus on colocation and interconnection services. Such services would provide additional value to our customers as they manage their infrastructure with our IBX hubs. Examples of recent new services include our IBX Link service which allows customers to easily move traffic between IBX centers located in the same metro area and the Financial Exchange service which allows direct interconnection with electronic financial exchanges.

Recent Developments

IXEurope Acquisition

On September 14, 2007, our wholly-owned subsidiary in the United Kingdom closed the purchase of the entire issued and to be issued share capital of IXEurope plc, which we refer to as the IXEurope acquisition. Under the final terms of the IXEurope acquisition, IXEurope shareholders will receive 140 British pence in cash for each IXEurope share valuing the share capital of IXEurope on a fully diluted basis at approximately 270.1 million British pounds or approximately $548.4 million (based on exchange rates as of September 13, 2007). We have until September 28, 2007 to pay the purchase price for the IXEurope acquisition, and we plan to use the proceeds of this offering and our concurrent notes offering for that purpose. IXEurope operates data centers in the United Kingdom, France, Germany and Switzerland. Equinix will integrate IXEurope’s business and operations under the Equinix brand. The current IXEurope management team is expected to join Equinix and continue to operate the European business.

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San Jose Property Acquisition

In July 2007, we closed on the $65.0 million conditional purchase agreement we signed in January 2007 to purchase the building and property where our original Silicon Valley IBX center is located. We refer to this transaction as the San Jose property acquisition.

Chicago IBX Financing

In July and August 2007, we received additional advances totaling $19.1 million, bringing the cumulative loan payable to date under the Chicago IBX financing to $88.3 million with a blended interest rate of 8.125% per annum. As a result, the remaining amount available to borrow from the Chicago IBX financing totals $21.7 million.

Asia-Pacific Financing

In August 2007, two of our wholly-owned subsidiaries, located in Singapore and Tokyo, Japan, entered into a multi-currency credit facility agreement for approximately $40.0 million in local currency equivalents. We refer to this transaction as the Asia-Pacific financing. The Asia-Pacific financing has a four-year term that allows these two subsidiaries to borrow up to approximately 23.0 million Singapore dollars and 2.9 billion Japanese yen during the first 12-month period with repayment to occur over the remaining three years in twelve equal quarterly installments. Amounts undrawn at the end of the first 12-month period shall be canceled and will no longer be available for borrowing. The Asia-Pacific financing bears interest at a floating rate (the relevant three-month local cost of funds for Singapore and Japan, as applicable, plus a margin ranging from 1.85% to 2.50%) with interest payable quarterly. The Asia-Pacific financing may be used by these two subsidiaries to fund capital expenditures on leasehold improvements, equipment, and other installation costs related to IBX expansion plans in Singapore and Tokyo. The Asia-Pacific financing has several financial covenants with which we must comply quarterly, is guaranteed by Equinix and is secured by the assets of the two subsidiaries. In September 2007, we borrowed approximately 18.3 million Singapore dollars at a local borrowing rate of 4.6625% and approximately 1.5 billion Japanese yen at a local borrowing rate of 2.687%. Collectively the amounts borrowed equal approximately $24.8 million leaving approximately $15.2 million remaining to borrow under the Asia-Pacific financing.

Company Information

Our principal executive offices are located at 301 Velocity Way, Fifth Floor, Foster City, CA 94404 and our telephone number is (650) 513-7000. Our website is located at www.equinix.com. Information contained on or accessible through our website is not part of this prospectus.

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The Offering

Concurrent Notes Offering

Concurrently with this offering, we are offering $300.0 million aggregate principal amount of     % Convertible Subordinated Notes due 2014 (or a total of $345.0 million aggregate principal amount of notes if the underwriters exercise their over-allotment option in full) pursuant to a separate registration statement and prospectus. It is possible that, based on market conditions, we may increase or decrease the number of shares offered hereby and increase or decrease the aggregate principal amount of the notes offered in our concurrent notes offering or complete one offering without the other. In any event, through this offering and our concurrent notes offering we intend to raise gross proceeds of approximately $600.0 million (up to $690.0 million if the underwriters’ over-allotment option for each offering is exercised in full). To the extent we enter into underwriting agreements for both offerings, the completion of each offering will be conditioned upon the concurrent completion of the other offering.

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Summary Consolidated Financial Data

The following summary consolidated financial data should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements and their related notes incorporated by reference into this prospectus and “Use of Proceeds” and “Capitalization.” The historical financial information presented below may not be indicative of our future performance. The historical summary consolidated financial data of IXEurope is not presented below. The audited financial statements of IXEurope for the three years ended December 31, 2006 and the unaudited financial statements of IXEurope for the six months ended June 30, 2006 and 2007 are incorporated into this prospectus by reference. The “Unaudited Pro Forma Combined Consolidated Condensed Financial Statements” are located elsewhere in this prospectus.

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RISK FACTORS

Any investment in our common stock involves a high degree of risk. You should consider the risks described below carefully and all of the information contained in this prospectus before deciding whether to purchase our common stock. The risks and uncertainties described below are not the only risks and uncertainties we face. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also impair our business operations. If any of the events described in the following risks actually occur, our business, financial condition and results of operations could suffer. In that event, the price of our common stock could decline, and you may lose all or part of your investment in our common stock. The risks discussed below also include forward-looking statements and our actual results may differ substantially from those discussed in these forward-looking statements. See “Forward-Looking Statements.”

Risks Related to the Acquisition of IXEurope

We may not be able to successfully integrate IXEurope and achieve the benefits we expect from the IXEurope acquisition.

We will only achieve the benefits that are expected to result from the IXEurope acquisition if we can successfully integrate its administrative, finance, operations, sales and marketing organizations, and implement appropriate systems and controls.

The success of the IXEurope acquisition and integration into our operations will involve a number of risks, including:

If we fail to integrate IXEurope successfully and/or fail to realize the intended benefits of the IXEurope acquisition, our results of operations could be materially and adversely affected. In addition, the IXEurope acquisition will result in a substantial goodwill asset, which will be subject to an annual impairment analysis. If this goodwill were to be impaired in the future, it could have a significant negative impact on our results of operations.

Risks Related to Our Business

Our substantial debt could adversely affect our cash flow and limit our flexibility to raise additional capital.

We have a significant amount of debt. As of June 30, 2007, our total indebtedness was approximately $543.1 million, and our total indebtedness would have been $930.2 million on a pro forma basis. Our substantial level of debt could have important consequences. For example, it could:

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The occurrence of any of the foregoing factors could have a material adverse effect on our business, results of operations and financial condition.

We have incurred substantial losses in the past and may continue to incur additional losses in the future.

Although we have generated cash from operations since the quarter ended September 30, 2003, for the years ended December 31, 2004, 2005 and 2006, we incurred net losses of $68.6 million, $42.6 million and $6.4 million, respectively. Furthermore, for the six months ended June 30, 2007, we incurred an additional net loss of $3.2 million. Although our net losses have generally been decreasing in recent quarters, we are also currently investing heavily in our future growth through the build-out of several additional IBX centers and IBX center expansions. As a result, we will incur higher depreciation and other operating expenses that will negatively impact our ability to achieve and sustain profitability unless and until these new IBX centers generate enough revenue to exceed their operating costs and cover our additional overhead needed to scale our business for this anticipated growth. In addition, costs associated with the IXEurope acquisition and the integration of the two companies, as well as the additional interest expense associated with debt financing we intend to undertake to fund our growth initiatives, may also negatively impact our ability to achieve and sustain profitability. Although our goal is to achieve profitability, there can be no guarantee that we will become profitable, and we may continue to incur additional losses. Even if we achieve profitability, given the competitive and evolving nature of the industry in which we operate, we may not be able to sustain or increase profitability on a quarterly or annual basis.

We are continuing to invest in our expansion efforts but may not have sufficient customer demand in the future to realize expected returns on these investments.

We are considering the acquisition or lease of additional properties, including construction of new IBX centers beyond those expansion projects already announced. We will be required to commit substantial operational and financial resources to these IBX centers, generally 12–18 months in advance of securing customer contracts, and we may not have sufficient customer demand in those markets to support these centers once they are built. In addition, unanticipated technological changes could affect customer requirements for data centers and we may not have built such requirements into our new IBX centers. Any of these contingencies, if they were to occur, could make it difficult for us to realize expected or reasonable returns on these investments.

We have begun construction of new IBX centers, and may begin construction of additional new IBX centers, which could involve significant risks to our business.

We believe that most of the pre-existing built-out data centers have already been acquired, and that there are few if any viable distressed assets available for us to acquire in our key markets today. In order to sustain our growth in these markets, we must acquire suitable land with or without structures to build our new IBX centers

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from the ground up, a “greenfield build.” Greenfield builds are currently underway in the Chicago, Los Angeles, Washington D.C. and New York metro areas. A greenfield build involves substantial planning and lead-time, much longer time to completion than we have currently experienced in our recent IBX retrofits of existing data centers, and significantly higher costs of construction, equipment and materials, which could have a negative impact on our returns. A greenfield build also requires us to carefully select and rely on the experience of one or several general contractors and associated subcontractors during the construction process. Should a general contractor or significant subcontractor experience financial or other problems during the construction process, we could experience significant delays, increased costs to complete the project and other negative impacts to our expected returns. Site selection is also a critical factor in our expansion plans, and there may not be suitable properties available in our markets with the necessary combination of high power capacity and fiber connectivity.

While we may prefer to locate new IBX centers adjacent to our existing locations, we may be limited by the inventory and location of suitable properties as well as the need for adequate power and fiber to the site. In the event we decide to build new IBX centers separate from our existing IBX centers, we may provide services to interconnect these two centers. Should these services not provide the necessary reliability to sustain service, this could result in lower interconnection revenue, lower margins and could have a negative impact on customer retention over time.

If we are not able to generate sufficient operating cash flow or obtain external financing, our ability to fund capital expenditures or fulfill our obligations or execute expansion plans may be limited.

Our capital expenditures, together with ongoing operating expenses and obligations to service our debts, will be a substantial drain on our cash flow and may decrease our cash balances. We regularly assess markets for external financing opportunities, including debt and equity. Additional debt or equity financing may not be available when needed or, if available, may not be available on satisfactory terms. Our inability to obtain needed debt and/or equity financing or to generate sufficient cash from operations may require us to abandon projects or curtail capital expenditures. If we curtail capital expenditures or abandon projects, we could be materially adversely affected.

Any failure of our physical infrastructure or services could lead to significant costs and disruptions that could reduce our revenue and harm our business reputation and financial results.

Our business depends on providing customers with highly reliable service. We must protect our customers’ IBX infrastructure and their equipment located in our IBX centers. We continue to acquire IBX centers not built by us. If these IBX centers and their infrastructure assets are not in the condition we believe them to be in, we may be required to incur substantial additional costs to repair or upgrade the centers. The services we provide in each of our IBX centers are subject to failure resulting from numerous factors, including:

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Problems at one or more of our IBX centers, whether or not within our control, could result in service interruptions or significant equipment damage. For example, in the event of an unusually long period of extreme heat, we may not be able to keep certain of our centers in compliance with our stated cooling objectives or the center’s cooling units could fail under the strain. The extreme temperatures could also lead to our suppliers experiencing electrical power outages or shortages. We have service level commitment obligations to certain of our customers, including our significant customers. As a result, service interruptions or significant equipment damage in our IBX centers could result in difficulty maintaining service level commitments to these customers and potential claims related to such failures. For example, for the year ended December 31, 2005, we recorded $457,000 in service level credits to various customers, primarily associated with two separate power outages that affected our Chicago and Washington, D.C. metro area IBX centers.

If we incur significant financial commitments to our customers in connection with a loss of power, or our failure to meet other service level commitment obligations, our liability insurance may not be adequate. In addition, any loss of services, equipment damage or inability to meet our service level commitment obligations could reduce the confidence of our customers and could consequently impair our ability to obtain and retain customers, which would adversely affect both our ability to generate revenues and our operating results.

Furthermore, we are dependent upon Internet service providers, telecommunications carriers and other website operators in the U.S., Asia, Europe and elsewhere, some of which have experienced significant system failures and electrical outages in the past. Users of our services may in the future experience difficulties due to system failures unrelated to our systems and services. If for any reason, these providers fail to provide the required services, our business, financial condition and results of operations could be materially adversely impacted.

A portion of our managed services business in Singapore involves the processing and storage of confidential customer information. Inappropriate use of those services could jeopardize the security of customers’ confidential information causing losses of data or financially impacting our customers or us and subjecting us to the risk of lawsuits. Efforts to alleviate problems caused by computer viruses or other inappropriate uses or security breaches may lead to interruptions, delays or cessation of our managed services.

There is no known prevention or defense against denial of service attacks. During a prolonged denial of service attack, Internet service may not be available for several hours, thus negatively impacting hosted customers’ on-line business transactions. Affected customers might file claims against us under such circumstances. Our property and liability insurance may not be adequate to cover these customer claims.

We expect our operating results to fluctuate.

We have experienced fluctuations in our results of operations on a quarterly and annual basis. The fluctuations in our operating results may cause the market price of our common stock to decline. We expect to experience significant fluctuations in our operating results in the foreseeable future due to a variety of factors, including, but not limited to:

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Any of the foregoing factors, or other factors discussed elsewhere in this prospectus, could have a material adverse effect on our business, results of operations and financial condition. Although we have experienced growth in revenues in recent quarters, this growth rate is not necessarily indicative of future operating results. We have generated net losses every fiscal year since inception. Furthermore, for the six months ended June 30, 2007, we incurred an additional net loss of $3.2 million. It is possible that we may not be able to generate positive net income on a quarterly or annual basis in the future. In addition, a relatively large portion of our expenses are fixed in the short-term, particularly with respect to lease and personnel expenses, depreciation and amortization and interest expenses. Therefore, our results of operations are particularly sensitive to fluctuations in revenues. As such, comparisons to prior reporting periods should not be relied upon as indications of our future performance. In addition, our operating results in one or more future quarters may fail to meet the expectations of securities analysts or investors. If this occurs, we could experience an immediate and significant decline in the trading price of our stock.

Our inability to use our tax net operating losses will cause us to pay taxes at an earlier date and in greater amounts, which may harm our operating results.

We believe that our ability to use our pre-2003 tax net operating losses, or NOLs, in any taxable year is subject to limitations under Section 382 of the United States Internal Revenue Code of 1986, as amended, or the Code, as a result of the significant change in the ownership of our stock that resulted from our combination with i-STT Pte Ltd and Pihana Pacific, Inc. in 2002, which we call the combination. We expect that a significant portion of our NOLs that accrued prior to December 31, 2002 will expire unused as a result of this limitation. In addition to the limitations on NOL carry-forward utilization described above, we believe that Section 382 of the Code will also significantly limit our ability to use the depreciation and amortization on our assets, as well as certain losses on the sale of our assets, to the extent that such depreciation, amortization and losses reflect unrealized depreciation that was inherent in such assets as of the date of the combination. These limitations will cause us to pay taxes at an earlier date and in greater amounts than would occur absent such limitations.

We are exposed to potential risks from legislation requiring companies to evaluate controls under Section 404 of the Sarbanes-Oxley Act of 2002.

Although we received an unqualified opinion regarding the effectiveness of our internal controls over financial reporting as of December 31, 2006, in the course of our ongoing evaluation of our internal controls over financial reporting, we have identified certain areas which we would like to improve and are in the process of

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evaluating and designing enhanced processes and controls to address these areas identified during our evaluation, none of which we believe constitutes or will constitute a material change. However, we cannot be certain that our efforts will be effective or sufficient for us, or our independent registered public accounting firm, to issue unqualified reports in the future, especially as our business continues to grow and evolve.

It may be difficult to design and implement effective financial controls for combined operations, and differences in existing controls of any acquired businesses, including IXEurope, may result in weaknesses that require remediation when the financial controls and reporting are combined.

Our ability to manage our operations and growth will require us to improve our operational, financial and management controls, as well as our internal reporting systems and controls. We may not be able to implement improvements to our internal reporting systems and controls in an efficient and timely manner and may discover deficiencies in existing systems and controls.

If we cannot effectively manage our international operations and successfully implement our international expansion plans, our revenues may not increase and our business and results of operations would be harmed.

For the years ended December 31, 2004, 2005 and 2006, we recognized 13%, 13% and 14%, respectively, of our revenues outside North America. For the six months ended June 30, 2007, we recognized 15% of our revenues outside North America. We anticipate that the acquisition of IXEurope will increase the percentage of our revenues derived from sources outside North America.

To date, the neutrality of our IBX centers and the variety of networks available to our customers has often been a competitive advantage for us. In certain of our acquired IBX centers, in Singapore in particular, the limited number of carriers available reduces that advantage. As a result, we may need to adapt our key revenue-generating services and pricing to be competitive in that market.

We may experience gains and losses resulting from fluctuations in foreign currency exchange rates. To date, the majority of our revenues and costs have been denominated in U.S. dollars; however, the majority of revenues and costs in our international operations have been denominated in Singapore dollars, Japanese yen and Australia and Hong Kong dollars. With the completion of the IXEurope acquisition, certain of our revenues and costs will also be denominated in the British pound sterling, the euro and the Swiss franc. Although we have in the past and may decide to undertake foreign exchange hedging transactions in the future to reduce foreign currency transaction exposure, we do not currently intend to eliminate all foreign currency transaction exposure. Where our prices are denominated in U.S. dollars, our sales could be adversely affected by declines in foreign currencies relative to the U.S. dollar, thereby making our products and services more expensive in local currencies.

We are currently undergoing expansions or evaluating expansion opportunities in Europe and in the Asia-Pacific region. Undertaking and managing expansions in foreign jurisdictions may present unanticipated challenges to us. In addition, any expansion requires substantial operational and financial resources, and we may not have sufficient customer demand to support the expansion once complete. Unanticipated technological changes could also affect customer requirements for data centers and we may not have built such requirements into our expanded IBX centers. We are also exposed to risks resulting from fluctuations in foreign currency exchange rates in connection with our international expansions. To the extent we are paying contractors in foreign currencies, our expansions could cost more than anticipated from declines in the U.S dollar relative to foreign currencies.

Our international operations are generally subject to a number of additional risks, including:

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The increased use of high power density equipment may limit our ability to fully utilize our IBX centers.

Customers are increasing their use of high-density electrical power equipment, such as blade servers, in our IBX centers which has significantly increased the demand for power on a per cabinet basis. Because most of our centers were built several years ago, the current demand for electrical power may exceed the designed electrical capacity in these centers. As electrical power, not space, is typically the limiting factor in our IBX data centers, our ability to fully utilize those IBX centers may be limited. The availability of sufficient power may also pose a risk to the successful operation of our new IBX centers. The ability to increase the power capacity of an IBX, should we decide to, is dependent on several factors including, but not limited to, the local utility’s ability to provide additional power; the length of time required to provide such power; and/or whether it is feasible to upgrade the electrical infrastructure of an IBX to deliver additional power to customers. Although we are currently designing and building to a much higher power specification, there is a risk that demand will continue to increase and our IBX centers could become obsolete sooner than expected.

We have made, and may continue to make, acquisitions which pose integration and other risks that could harm our business.

We have recently acquired several new IBX centers, and we may seek to acquire additional IBX centers, real estate for development of new IBX centers, or complementary businesses, such as IXEurope, products, services or technologies. As a result of these acquisitions, we may be required to incur additional debt and expenditures and issue additional shares of our common stock to pay for the acquired businesses, products, services or technologies, which may dilute our stockholders’ ownership interest and may delay, or prevent, our profitability. These acquisitions may also expose us to risks such as:

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We cannot assure you that the price for any future acquisitions will be similar to prior IBX acquisitions. In fact, we expect acquisition costs, including capital expenditures required to build or render new IBX centers operational, to increase in the future. If our revenue does not keep pace with these potential acquisition and expansion costs, we may not be able to maintain our current or expected margins as we absorb these additional expenses. There is no assurance we would successfully overcome these risks or any other problems encountered with these acquisitions.

Our business could be harmed by prolonged electrical power outages or shortages, increased costs of energy or general lack of availability of electrical resources.

Our IBX centers are susceptible to regional costs of power, electrical power shortages, planned or unplanned power outages and limitations, especially internationally, on the availability of adequate power resources.

Power outages, such as those that occurred in California during 2001, the Northeast in 2003 and from the tornados on the U.S. east coast in 2004, could harm our customers and our business. We attempt to limit exposure to system downtime by using backup generators and power supplies; however, we may not be able to limit our exposure entirely even with these protections in place, as was the case with the power outages we experienced in our Chicago and Washington, D.C. metro area IBX centers in 2005.

In addition, global fluctuations in the price of power can increase the cost of energy, and although contractual price increase clauses may exist in some of our customer agreements, we may not be able to pass these increased costs on to our customers.

In each of our markets, we rely on third parties to provide a sufficient amount of power for current and future customers. At the same time, power and cooling requirements are growing on a per unit basis. As a result, some customers are consuming an increasing amount of power per cabinet. We generally do not control the amount of electric power our customers draw from their installed circuits. This means that we could face power limitations in our centers. This could have a negative impact on the effective available capacity of a given center and limit our ability to grow our business, which could have a negative impact on our financial performance, operating results and cash flows.

We may also have difficulty obtaining sufficient power capacity for potential expansion sites in new or existing markets. We may experience significant delays and substantial increased costs demanded by the utilities to provide the level of electrical service required by our current IBX center designs.

We may be forced to take steps, and may be prevented from pursuing certain business opportunities, to ensure compliance with certain tax-related covenants agreed to by us in connection with the combination.

We agreed to a covenant in connection with the combination (which we refer to as the FIRPTA covenant) that we would use all commercially reasonable efforts to ensure that at all times from and after the closing of the combination none of our capital stock issued to STT Communications would constitute “United States real property interests” within the meaning of Section 897(c) of the Code. Under Section 897(c) of the Code, our capital stock issued to STT Communications would generally constitute “United States real property interests” at such point in time that the fair market value of the “United States real property interests” owned by us equals or exceeds 50% of the sum of the aggregate fair market values of (a) our “United States real property interests,” (b) our interests in real property located outside the United States and (c) any other assets held by us which are used or held for use in our trade or business. Currently, the fair market value of our “United States real property interests” is significantly below the 50% threshold. However, in order to ensure compliance with the FIRPTA covenant, we may be limited with respect to the business opportunities we may pursue, particularly if the business opportunities would increase the amounts of “United States real property interests” owned by us or decrease the amount of other assets owned by us. In addition, we may take proactive steps to avoid our capital stock being deemed a “United States real property interest,” including, but not limited to, (a) a sale-leaseback

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transaction with respect to some or all of our real property interests, or (b) the formation of a holding company organized under the laws of the Republic of Singapore which would issue shares of its capital stock in exchange for all of our outstanding stock (which would require the submission of that transaction to our stockholders for their approval and the consummation of that exchange). We will take these actions only if such actions are commercially reasonable for our stockholders and us. We have entered into an agreement with STT Communications and its affiliate pursuant to which we will no longer be bound by the FIRPTA covenant as of September 30, 2009. If we were to breach this covenant, we may be liable for damages to STT Communications.

Increases in property taxes could adversely affect our business, financial condition and results of operations.

Our IBX centers are subject to state and local real property taxes in the U.S. and certain of our European jurisdictions. The state and local real property taxes on our IBX centers may increase as property tax rates change and as the value of the properties are assessed or reassessed by taxing authorities. Many state and local governments are facing budget deficits, which may cause them to increase assessments or taxes. If property taxes increase, our business, financial condition and operating results could be adversely affected.

STT Communications has voting control over a substantial portion of our stock and has influence over matters requiring stockholder consent.

As of June 30, 2007, STT Communications, through its subsidiary, i-STT Investments (Bermuda) Ltd., had voting control over approximately 13.5% of our outstanding common stock. In addition, STT Communications is not prohibited from buying shares of our stock in public or private transactions. As a result, STT Communications is able to exercise significant control over all matters requiring stockholder approval, including the election of directors and approval of significant corporate transactions, which could prevent or delay a third party from acquiring or merging with us.

Our non-U.S. customers include numerous related parties of STT Communications.

We continue to have contractual and other business relationships and may engage in material transactions with affiliates of STT Communications. Circumstances may arise in which the interests of STT Communications’ affiliates may conflict with the interests of our other stockholders. In addition, entities affiliated with STT Communications make investments in various companies. They have invested in the past, and may invest in the future, in entities that compete with us. In the context of negotiating commercial arrangements with affiliates, conflicts of interest have arisen in the past and may arise, in this or other contexts, in the future. We cannot assure you that any conflicts of interest will be resolved in our favor.

If regulated materials are discovered at centers leased or owned by us, we may be required to remove or clean-up such materials, the cost of which could be substantial.

We are subject to various environmental and health and safety laws and regulations, including those relating to the generation, storage, handling and disposal of hazardous substances and wastes. Certain of these laws and regulations also impose joint and several liability, without regard to fault, for investigation and cleanup costs on current and former owners and operators of real property and persons who have disposed of or released hazardous substances into the environment. Our operations involve the use of hazardous substances and materials such as petroleum fuel for emergency generators, as well as batteries, cleaning solutions and other materials. In addition, we lease, own or operate real property at which hazardous substances and regulated materials have been used in the past. At some of our locations, hazardous substances or regulated materials are known to be present in soil or groundwater and there may be additional unknown hazardous substances or regulated materials present at sites we own, operate or lease. At some of our locations, there are land use restrictions in place relating to earlier environmental cleanups that do not materially limit our use of the sites. To the extent any hazardous substances or any other substance or material must be cleaned up or removed from our property, we may be responsible

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under applicable laws, regulations or leases for the removal or cleanup of such substances or materials, the cost of which could be substantial. In addition, noncompliance with existing, or adoption of more stringent, environmental or health and safety laws and regulations or the discovery of previously unknown contamination could require us to incur costs or become the basis of new or increased liabilities that could be material.

We depend on a number of third parties to provide Internet connectivity to our IBX centers; if connectivity is interrupted or terminated, our operating results and cash flow could be materially adversely affected.

The presence of diverse telecommunications carriers’ fiber networks in our IBX centers is critical to our ability to retain and attract new customers. We are not a telecommunications carrier, and as such we rely on third parties to provide our customers with carrier services. We believe that the availability of carrier capacity will directly affect our ability to achieve our projected results. We rely primarily on revenue opportunities from the telecommunications carriers’ customers to encourage them to invest the capital and operating resources required to connect from their centers to our IBX centers. Carriers will likely evaluate the revenue opportunity of an IBX center based on the assumption that the environment will be highly competitive. We cannot assure you that any carrier will elect to offer its services within our IBX centers or that once a carrier has decided to provide Internet connectivity to our IBX centers that it will continue to do so for any period of time. Further, many carriers are experiencing business difficulties or announcing consolidations. As a result, some carriers may be forced to downsize or terminate connectivity within our IBX centers, which could have an adverse effect on our operating results.

Our new IBX centers require construction and operation of a sophisticated redundant fiber network. The construction required to connect multiple carrier facilities to our IBX centers is complex and involves factors outside of our control, including regulatory processes and the availability of construction resources. If the establishment of highly diverse Internet connectivity to our IBX centers does not occur, is materially delayed or is discontinued, or is subject to failure, our operating results and cash flow will be adversely affected. Any hardware or fiber failures on this network may result in significant loss of connectivity to our new IBX expansion centers. This could affect our ability to attract new customers to these IBX centers or retain existing customers.

Our networks may be vulnerable to unauthorized persons accessing our systems, which could disrupt our operations and result in the theft of our proprietary information.

A party who is able to breach the security measures on our networks could misappropriate either our proprietary information or the personal information of our customers, or cause interruptions or malfunctions in our operations. We may be required to expend significant capital and resources to protect against such threats or to alleviate problems caused by breaches in security, which could have a material adverse effect on our financial performance and operating results.

A small number of customers, including IBM, account for a significant portion of our revenues, and the loss of any of these customers could significantly harm our business, financial condition and results of operations.

While no single customer accounted for 10% of our revenues for the year ended December 31, 2006 and the six months ended June 30, 2007, our top ten customers accounted for 25% and 24%, respectively, of our revenues during these periods. As of June 30, 2007, we had 1,373 customers. Notwithstanding our acquisition of IXEurope and the integration of its customer base with ours, we expect that a small percentage of our customers will continue to account for a significant portion of our revenues for the foreseeable future. We cannot guarantee that we will retain these customers or that they will maintain their commitments in our IBX centers at current levels. For example, although the term of our contract with IBM, our single largest customer, runs through 2011, IBM currently has the right to reduce its commitment to us pursuant to the terms and requirements of its customer agreement. If we lose any of these key customers, or if any of them decide to reduce the level of their commitment to us, our business, financial condition and results of operations could be adversely affected.

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We resell products and services of third parties that may require us to pay for such products and services even if our customers fail to pay us for the products and services, which may have a negative impact on our operating results.

In order to provide resale services such as bandwidth, managed services and other network management services, we contract with third party service providers. These services require us to enter into fixed term contracts for services with third party suppliers of products and services. If we experience the loss of a customer who has purchased a resale product, we will remain obligated to continue to pay our suppliers for the term of the underlying contracts. The payment of these obligations without a corresponding payment from customers will reduce our financial resources and may have a material adverse effect on our operating and financial results and cash flows.

We may not be able to compete successfully against current and future competitors.

Our IBX centers and other products and services must be able to differentiate themselves from those of other providers of space and services for telecommunications companies, web-hosting companies and other colocation providers. In addition to competing with neutral colocation providers, we must compete with traditional colocation providers, including local phone companies, long distance phone companies, Internet service providers and web-hosting facilities. Similarly, with respect to our other products and services, including managed services, bandwidth services and security services, we must compete with more established providers of similar services. Most of these companies have longer operating histories and significantly greater financial, technical, marketing and other resources than us.

Because of their greater financial resources, some of our competitors have the ability to adopt aggressive pricing policies, especially if they have been able to restructure their debt or other obligations. As a result, in the future, we may suffer from pricing pressure that would adversely affect our ability to generate revenues and adversely affect our operating results. In addition, these competitors could offer colocation on neutral terms, and may start doing so in the same metropolitan areas in which we have IBX centers. Some of these competitors may also provide our target customers with additional benefits, including bundled communication services, and may do so in a manner that is more attractive to our potential customers than obtaining space in our IBX centers. If these competitors were able to adopt aggressive pricing policies together with offering colocation space, our ability to generate revenues would be materially adversely affected.

We may also face competition from persons seeking to replicate our IBX concept by building new centers or converting existing centers that some of our competitors are in the process of divesting. We may continue to see increased competition for data center space and customers from large REITS who also operate in our market. We may experience competition from our landlords, some of which are REITS, in this regard. Rather than leasing available space in our buildings to large single tenants, they may decide to convert the space instead to smaller square foot units designed for multi-tenant colocation use. Landlords/REITS may enjoy a cost effective advantage in providing services similar to those provided by our IBXs, and in addition to the risk of losing customers to these parties this could also reduce the amount of space available to us for expansion in the future. Competitors may operate more successfully or form alliances to acquire significant market share. Furthermore, enterprises that have already invested substantial resources in outsourcing arrangements may be reluctant or slow to replace, limit or compete with their existing systems by becoming a customer. Customers may also decide it is cost effective for them to build out their own data centers which could have a negative impact on our results of operations. In addition, other companies may be able to attract the same potential customers that we are targeting. Once customers are located in competitors’ facilities, it may be extremely difficult to convince them to relocate to our IBX centers.

Because we depend on the retention of key employees, failure to maintain competitive compensation packages, including equity incentives, may be disruptive to our business.

Our success in retaining key employees and discouraging them from moving to a competitor is an important factor in our ability to remain competitive. As is common in our industry, our employees are typically compensated through grants of equity awards in addition to their regular salaries. In addition to granting equity

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awards to selected new hires, we periodically grant new equity awards to certain employees as an incentive to remain with us. To the extent we are unable to offer competitive compensation packages to our employees and adequately maintain equity incentives due to equity expensing or otherwise, and should employees decide to leave us, this may be disruptive to our business and may adversely affect our business, financial condition and results of operations.

Because we depend on the development and growth of a balanced customer base, failure to attract and retain this base of customers could harm our business and operating results.

Our ability to maximize revenues depends on our ability to develop and grow a balanced customer base, consisting of a variety of companies, including network service providers, site and performance management companies, and enterprise and content companies. The more balanced the customer base within each IBX center, the better we will be able to generate significant interconnection revenues, which in turn increases our overall revenues. Our ability to attract customers to our IBX centers will depend on a variety of factors, including the presence of multiple carriers, the mix of products and services offered by us, the overall mix of customers, the IBX center’s operating reliability and security and our ability to effectively market our services. In addition, some of our customers are, and are likely to continue to be, Internet companies that face many competitive pressures and that may not ultimately be successful. If these customers do not succeed, they will not continue to use the IBX centers. This may be disruptive to our business and may adversely affect our business, financial condition and results of operations.

Our products and services have a long sales cycle that may materially adversely affect our business, financial condition and results of operations.

A customer’s decision to license cabinet space in one of our IBX centers and to purchase additional services typically involves a significant commitment of resources. In addition, some customers will be reluctant to commit to locating in our IBX centers until they are confident that the IBX center has adequate carrier connections. As a result, we have a long sales cycle. Furthermore, we may expend significant time and resources in pursuing a particular sale or customer that does not result in revenue. Delays due to the length of our sales cycle may materially adversely affect our business, financial condition and results of operations.

The failure to obtain favorable terms when we renew our IBX center leases could harm our business and results of operations.

While we own certain of our IBX centers, others are leased under long-term arrangements with lease terms expiring at various dates ranging from 2010 to 2025. These leased centers have all been subject to significant development by us in order to convert them from, in most cases, vacant buildings or warehouses into IBX centers. All of our IBX center leases have renewal options available to us. However, these renewal options provide for rent set at then-prevailing market rates. To the extent that then-prevailing market rates are higher than present rates, these higher costs may adversely impact our business and results of operations.

If the market price of our stock continues to be highly volatile, the value of an investment in our common stock may decline.

Since January 1, 2006, the closing sale price of our common stock on the NASDAQ Global Select Market ranged from $41.43 to $96.99 per share. The market price of the shares of our common stock has been and may continue to be highly volatile. Actual sales, or the market’s perception with respect to possible sales, of a substantial number of shares of our common stock within a narrow period of time could cause our stock price to fall. Announcements by others or us may also have a significant impact on the market price of our common stock. These announcements may include:

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The stock market has from time to time experienced extreme price and volume fluctuations, which have particularly affected the market prices for emerging telecommunications companies, and which have often been unrelated to their operating performance. These broad market fluctuations may adversely affect the market price of our common stock.

We are subject to securities class action and derivative litigation, which may harm our business and results of operations.

In the past, securities class action litigation has often been brought against a company following periods of volatility in the market price of its securities. During the quarter ended September 30, 2001, putative shareholder class action lawsuits were filed against us, a number of our officers and directors, and several investment banks that were underwriters of our initial public offering. Similar complaints were filed against more than 300 other issuers, their officers and directors, and investment banks. The suits allege that the underwriter defendants agreed to allocate stock in our initial public offering to certain investors in exchange for excessive and undisclosed commissions and agreements by those investors to make additional purchases in the aftermarket at pre-determined prices. Plaintiffs allege that the prospectus for our initial public offering was false and misleading and in violation of the securities laws because it did not disclose these arrangements. A previously agreed upon settlement with the plaintiffs has been terminated. On August 14, 2007, the plaintiffs filed amended complaints in six cases selected as test, or “focus,” cases (ours is not one of the “focus” cases). Plaintiffs plan to move for class certification this fall. If plaintiffs are successful in obtaining class certification in the “focus” cases, they will also likely file an amended complaint against us. We are continuing to participate in the defense of this litigation, which may increase our expenses and divert management’s attention and resources. In addition, we may, in the future, be subject to other securities class action or similar litigation.

On June 29, 2006 and September 18, 2006, shareholder derivative actions were filed in the Superior Court of the State of California, County of San Mateo, naming Equinix as a nominal defendant and several of Equinix’s current and former officers and directors as individual defendants. These actions were consolidated, and the consolidated complaint was filed in January 2007. The consolidated complaint alleges that the individual defendants breached their fiduciary duties and violated California securities law as a result of purported backdating of stock option grants, insider trading and the preparation and approval of inaccurate financial results. Plaintiffs seek to recover, on behalf of Equinix, unspecified monetary damages, corporate governance changes, equitable and injunctive relief, restitution and fees and costs. In March 2007, the state court stayed this action in deference to a federal shareholder derivative action filed in the United States District Court for the Northern District of California in October 2006. The federal action named Equinix as a nominal defendant and several current and former officers and directors as individual defendants. This complaint alleged that the individual defendants breached their fiduciary duties and violated California and federal securities laws as a result of purported backdating of stock options, insider trading and the dissemination of false statements. On April 12, 2007, the federal action was voluntarily dismissed without prejudice pursuant to a joint stipulation entered as an

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order by the court. On May 3, 2007, the state court lifted the stay on proceedings in the state court action and set a briefing schedule permitting us to file a motion to dismiss on the grounds that plaintiffs lack standing to sue on our behalf. We filed our motion to dismiss on June 4, 2007 and appeared for a hearing on the motion on August 6, 2007. The state court recently granted our motion to dismiss and granted plaintiffs leave to amend their consolidated complaint. In addition to the pending state court derivative action, we may be subject to additional derivative or other lawsuits that may be presented on an individual or class basis alleging claims based on our stock option granting practices. Responding to, investigating and/or defending against these complaints will present a substantial cost to us in both cash and the attention of certain management. Any adverse outcome in litigation could seriously harm our business and results of operations.

Risks Related to Our Industry

If the use of the Internet and electronic business does not grow, our revenues may not grow.

Acceptance and use of the Internet may not continue to develop at historical rates and a sufficiently broad base of consumers may not adopt or continue to use the Internet and other online services as a medium of commerce. Demand for Internet services and products are subject to a high level of uncertainty and are subject to significant pricing pressure, especially in Asia-Pacific. As a result, we cannot be certain that a viable market for our IBX centers will materialize. If the market for our IBX centers grows more slowly than we currently anticipate, our revenues may not grow and our operating results could suffer.

Government regulation may adversely affect the use of the Internet and our business.

Various laws and governmental regulations governing Internet related services, related communications services and information technologies and electronic commerce remain largely unsettled, even in areas where there has been some legislative action. This is true both in the U.S. and the various foreign countries in which we operate. It may take years to determine whether and how existing laws, such as those governing intellectual property, privacy, libel, telecommunications services and taxation, apply to the Internet and to related services such as ours. We have limited experience with such international regulatory issues and substantial resources may be required to comply with regulations or bring any non-compliant business practices into compliance with such regulations. In addition, the development of the market for online commerce and the displacement of traditional telephony service by the Internet and related communications services may prompt an increased call for more stringent consumer protection laws or other regulation both in the U.S. and abroad that may impose additional burdens on companies conducting business online and their service providers. The compliance with, adoption or modification of, laws or regulations relating to the Internet, or interpretations of existing laws, could have a material adverse effect on our business, financial condition and results of operation.

Industry consolidation may have a negative impact on our business model.

The telecommunications industry is currently undergoing consolidation. As customers combine businesses, they may require less colocation space, and there may be fewer networks available to choose from. Given the competitive and evolving nature of this industry, further consolidation of our customers and/or our competitors may present a risk to our network neutral business model and have a negative impact on our revenues. In addition, increased utilization levels industry-wide could lead to a reduced amount of attractive expansion opportunities available to us.

Terrorist activity throughout the world and military action to counter terrorism could adversely impact our business.

The September 11, 2001 terrorist attacks in the U.S., the ensuing declaration of war on terrorism and the continued threat of terrorist activity and other acts of war or hostility appear to be having an adverse effect on business, financial and general economic conditions internationally. These effects may, in turn, increase our costs

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due to the need to provide enhanced security, which would have a material adverse effect on our business and results of operations. These circumstances may also adversely affect our ability to attract and retain customers, our ability to raise capital and the operation and maintenance of our IBX centers. We may not have adequate property and liability insurance to cover catastrophic events or attacks.

Risks Related to this Offering

Sales of a significant number of shares of our common stock in the public markets, or the perception of such sales, could depress the market price of our common stock.

Sales of a substantial number of shares of our common stock or other equity-related securities in the public markets could depress the market price of our common stock and impair our ability to raise capital through the sale of additional equity securities. We cannot predict the effect that future sales of our common stock or other equity-related securities would have on the market price of our common stock. The price of our common stock could be affected by possible sales of our common stock by investors who view our equity-related securities as a more attractive means of equity participation in our company and by hedging or arbitrage trading activity which we expect to occur involving our common stock. This hedging or arbitrage could, in turn, affect the market price of our common stock.

Conversion of our outstanding equity-related securities and any notes sold pursuant to the concurrent notes offering will dilute the ownership interests of existing stockholders.

Upon conversion of any notes sold pursuant to the concurrent notes offering and, to the extent we deliver shares of our common stock upon conversion of our 2.50% Convertible Subordinated Notes due 2012 or our 2.50% Convertible Subordinated Debentures due 2024, the ownership interests of existing stockholders will be diluted. Any sales in the public market of our common stock issuable upon such conversion could adversely affect prevailing market prices of our common stock. In addition, the existence of such equity-related securities may encourage short selling by market participants because the conversion of such securities could depress the price of our common stock.

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USE OF PROCEEDS

We estimate that the proceeds from this offering, after deducting underwriting discounts and estimated offering expenses, will be approximately $287.6 million. If the underwriters exercise in full their over-allotment option to acquire additional shares, we estimate that our net proceeds from this offering will be approximately $330.8 million. We estimate that the net proceeds from our concurrent notes offering will be approximately $291.3 million or $335.1 million if the underwriters exercise their over-allotment option in full, after deducting the underwriting discounts and commissions and estimated offering expenses. It is possible that, based on market conditions, we may increase or decrease the number of shares offered hereby and increase or decrease the aggregate principal amount of the notes offered in our concurrent notes offering or complete one offering without the other. In any event, through this offering and our concurrent notes offering we intend to raise gross proceeds of approximately $600.0 million (up to $690.0 million if the underwriters’ over-allotment option for each offering is exercised in full). To the extent we enter into underwriting agreements for both offerings, the completion of each offering will be conditioned upon the concurrent completion of the other offering.

We expect to use the net proceeds from this offering, together with the net proceeds of our concurrent notes offering, to fund the acquisition of IXEurope. The total amount of funds that we need to acquire IXEurope and to pay related fees and expenses is approximately $548.4 million. We will allocate the amount of net proceeds to be used from each offering towards the acquisition at the time each offering is priced. Any net proceeds from this offering and our concurrent notes offering that are not used for the acquisition are expected to be used for capital expenditures, acquisitions or general corporate purposes. Pending application of the proceeds as described above, we intend to invest the proceeds in short-term, interest-bearing investment grade securities.

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CAPITALIZATION

The following table sets forth our cash, cash equivalents, short-term and long-term investments and current portion of our indebtedness and our capitalization as of June 30, 2007:

This table should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” the “Unaudited Pro Forma Combined Consolidated Condensed Financial Statements” and our financial statements, including all related notes, included or incorporated by reference in this prospectus.

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Our pro forma capitalization presented above reflects the sale of $300.0 million of our common stock offered hereby and a concurrent sale of $300.0 million aggregate principal amount of notes, reflecting total gross proceeds to us of $600.0 million from both offerings. It is possible that, based on market conditions, we may increase or decrease the number of shares offered hereby and increase or decrease the aggregate principal amount of the notes offered in our concurrent notes offering or complete one offering without the other. In any event, through this offering and our concurrent notes offering we intend to raise gross proceeds of approximately $600.0 million (up to $690.0 million if the underwriters’ over-allotment option for each offering is exercised in full). To the extent we enter into underwriting agreements for both offerings, the completion of each offering will be conditioned upon the concurrent completion of the other offering.

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MARKET FOR OUR COMMON STOCK AND DIVIDENDS

Our common stock is quoted on the NASDAQ Global Select Market under the symbol of “EQIX.” Our common stock began trading in August 2000. The following table sets forth on a per share basis the low and high closing prices of our common stock as reported by the NASDAQ Global Select Market since January 1, 2005.

The closing price of our common stock on the NASDAQ Global Select Market on September 13, 2007 was $81.91 per share. As of August 31, 2007, we had 32,030,738 shares of our common stock issued and outstanding held by approximately 256 registered holders.

We have never declared or paid any cash dividends on our common stock and we do not anticipate paying cash dividends in the foreseeable future. We currently intend to retain our earnings, if any, for future growth. Future dividends on our common stock, if any, will be at the discretion of our board of directors and will depend on, among other things, our operations, capital requirements and surplus, general financial condition, contractual restrictions and such other factors as our board of directors may deem relevant. Our ability to pay cash dividends is limited under our line of credit with Silicon Valley Bank, such that, without the prior written consent of Silicon Valley Bank, the aggregate amount of any cash dividends may not exceed 25% of our assets.

During the six months ended June 30, 2007, we did not issue or sell any unregistered securities.

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UNAUDITED PRO FORMA COMBINED CONSOLIDATED CONDENSED FINANCIAL STATEMENTS

The following unaudited pro forma combined consolidated condensed financial statements have been prepared to give effect to the acquisition by Equinix, Inc. (“Equinix” or the “Company”) of IXEurope plc (“IXEurope”) using the purchase method of accounting and the related financings to fund this acquisition with the assumptions and adjustments described in the accompanying notes to the unaudited pro forma combined consolidated condensed financial statements, as well as certain significant transactions of the Company that have occurred subsequent to June 30, 2007 consisting of (i) additional advances under the Chicago IBX Financing, (ii) the completion of the San Jose Property Acquisition and (iii) the Asia-Pacific Financing. These pro forma statements were prepared as if the acquisition and related financings and other transactions described above had been completed as of January 1, 2006 for statements of operations purposes and as of June 30, 2007 for balance sheet purposes. The combined company will operate under the Equinix name with the current management teams in place in the U.S., Europe and Asia-Pacific.

The unaudited pro forma combined consolidated condensed financial statements are presented for illustrative purposes only and are not necessarily indicative of the financial position or results of operations that would have actually been reported had the acquisition and related financings and other transactions described above occurred on January 1, 2006 for statements of operation purposes and as of June 30, 2007 for balance sheet purposes, nor is it necessarily indicative of the future financial position or results of operations of the combined company. The unaudited pro forma combined consolidated condensed financial statements include adjustments, which are based upon preliminary estimates, to reflect the allocation of the purchase price to the acquired assets and assumed liabilities of IXEurope. The final allocation of the purchase price will be determined after the completion of the acquisition and will be based upon actual net tangible and intangible assets acquired as well as liabilities assumed. The preliminary purchase price allocation for IXEurope is subject to revision as more detailed analysis is completed and additional information on the fair values of IXEurope’s assets and liabilities becomes available. Any change in the fair value of the net assets of IXEurope will change the amount of the purchase price allocable to goodwill. Additionally, changes in IXEurope’s working capital, including the results of operations from June 30, 2007 through September 14, 2007, the date the transaction was completed, will change the amount of goodwill recorded. Final purchase accounting adjustments may differ materially from the pro forma adjustments presented here.

These unaudited pro forma combined condensed financial statements are based upon the respective historical consolidated financial statements of Equinix and IXEurope, adjusted to generally accepted accounting principles in the United States of America, and should be read in conjunction with the historical consolidated financial statements of Equinix and IXEurope and related notes and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of Equinix and IXEurope incorporated in this document by reference.

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UNAUDITED PRO FORMA COMBINED CONDENSED BALANCE SHEET

AS OF JUNE 30, 2007

(In thousands)

The accompanying notes are an integral part of these unaudited pro forma combined condensed

financial statements.

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UNAUDITED PRO FORMA COMBINED CONDENSED STATEMENT OF OPERATIONS

FOR THE YEAR ENDED DECEMBER 31, 2006

(In thousands, except per share data)

The accompanying notes are an integral part of these unaudited pro forma combined condensed

financial statements.

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UNAUDITED PRO FORMA COMBINED CONDENSED STATEMENT OF OPERATIONS

FOR THE SIX MONTHS ENDED JUNE 30, 2007

(In thousands, except per share data)