GTT GTT Communications, Inc.

RISK FACTORS

An investment in our common stock involves a high degree of risk. Before deciding whether to invest in our common stock, you should consider carefully the risks described below, together with the other information in this prospectus supplement, the accompanying prospectus and the information and documents incorporated by reference. If any of these risks actually occurs, our business, financial condition, results of operations or cash flows could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment.

Risks Relating to Our Business and Operations

We depend on several large customers, and the loss of one or more of these customers, or a significant decrease in total revenue from any of these customers, would likely reduce our revenue and income.

For the year ended December 31, 2013, our five largest customers accounted for approximately 18% of our total service revenue. If we were to lose all of the underlying services from one or more of our large customers, or if one or more of our large customers were to significantly reduce the services purchased from us or otherwise renegotiate the terms on which services are purchased from us, our revenue could decline and our results of operations would suffer.

If our customers elect to terminate their agreements with us, our business, financial condition and results of operations may be adversely affected.

Our services are sold under agreements that generally have initial terms of between one and three years. Following the initial terms, these agreements generally automatically renew for successive month-to-month, quarterly or annual periods, but can be terminated by the customer without cause with relatively little notice during a renewal period. In addition, certain government customers may have rights under Federal law with respect to termination for convenience that can serve to minimize or eliminate altogether the liability payable by that customer in the event of early termination. Our customers may elect to terminate their agreements as a result of a number of factors, including their level of satisfaction with the services they are receiving, their ability to continue their operations due to budgetary or other concerns and the availability and pricing of competing services. If customers elect to terminate their agreements with us, our business, financial condition and results of operation may be adversely affected.

Competition in the industry in which we do business is intense and growing, and our failure to compete successfully could make it difficult for us to add and retain customers or increase or maintain revenue.

The markets in which we operate are rapidly evolving and highly competitive. We currently or potentially compete with a variety of companies, including some of our transport suppliers, with respect to their products and services, including global and regional telecommunications service providers such as AT&T, British Telecom, Deutsche Telecom, Level 3, and Verizon Business, among others.

The industry in which we operate is consolidating, which is increasing the size and scope of our competitors. Competitors could benefit from assets or businesses acquired from other carriers or from strategic alliances in the telecommunications industry. New entrants could enter the market with a business model similar to ours. Our target markets may support only a limited number of competitors. Operations in such markets with multiple competitive providers may be unprofitable for one or more of such providers. Prices in the data transmission and internet access business have declined in recent years and may continue to decline.

Many of our potential competitors have certain advantages over us, including:

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Our competitors may be able to use these advantages to:

If we are unable to compete successfully against our current and future competitors, our revenue and gross margin could decline and we would lose market share, which could materially and adversely affect our business.

We might require additional capital to support business growth, and this capital might not be available on favorable terms, or at all.

Our operations or expansion efforts may require substantial additional financial, operational and managerial resources. As of March 31, 2014, we had approximately $7.2 million in cash, and our current liabilities were $25.3 million greater than current assets. We may have insufficient cash to fund our working capital or other capital requirements and may be required to raise additional funds to continue or expand our operations. If we are required to obtain additional funding in the future, we may have to sell assets, seek debt financing, or obtain additional equity capital. Our ability to sell assets or raise additional equity or debt capital will depend on the condition of the capital and credit markets and our financial condition at such time. Accordingly, additional capital may not be available to us, or may only be available on terms that adversely affect our existing stockholders, or that restrict our operations. For example, if we raise additional funds through issuances of equity or convertible debt securities, our existing stockholders could suffer dilution, and any new equity securities we issue could have rights, preferences, and privileges superior to those of holders of our common stock. Also, if we were forced to sell assets, there can be no assurance regarding the terms and conditions we could obtain for any such sale, and if we were required to sell assets that are important to our current or future business, our current and future results of operations could be materially and adversely affected. We have granted security interests in substantially all of our assets to secure the repayment of our indebtedness maturing between 2014 and 2016, and if we are unable to satisfy our obligations, the lenders could foreclose on their security interests.

Because our business is dependent upon selling telecommunications network capacity purchased from third parties, the failure of our suppliers and other service providers to provide us with services, or disputes with those suppliers and service providers, could affect our ability to provide quality services to our customers and have an adverse effect on our operations and financial condition.

Much of our business consists of integrating and selling network capacity purchased from facility-based telecommunications carriers. Accordingly, we will be largely dependent on third parties to supply us with services. Occasionally in the past, our operating companies have experienced delays or other problems in receiving services from third-party providers. Disputes also arise from time to time with suppliers with respect to billing or interpretation of contract terms. Any failure on the part of third parties to adequately supply us or to maintain the quality of their facilities and services in the future, or the termination of any significant contracts by

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a supplier, could cause customers to experience delays in service and lower levels of customer care, which could cause them to switch providers. Furthermore, disputes over billed amounts or interpretation of contract terms could lead to claims against us, some of which if resolved against us could have an adverse impact on our results of operations and/or financial condition. Suppliers may also attempt to impose onerous terms as part of purchase contract negotiations. Although we know of no pending or threatened claims with respect to past compliance with any such terms, claims asserting any past noncompliance, if successful, could have a material adverse effect on our operations and/or financial condition. Moreover, to the extent that key suppliers were to attempt to impose such provisions as part of future contract negotiations, such developments could have an adverse impact on the company’s operations. Finally, some of our suppliers are potential competitors. We cannot guarantee that we will be able to obtain use of facilities or services in a timely manner or on terms acceptable and in quantities satisfactory to us.

Industry consolidation may affect our ability to obtain services from suppliers on a timely or cost-efficient basis.

A principal method of connecting with our customers is through local transport and last mile circuits we purchase from incumbent carriers such as AT&T and Verizon, or competitive carriers such as Time Warner Telecom, XO, or Level 3. In recent years, AT&T, Verizon, and Level 3 have acquired competitors with significant local and/or long-haul network assets. Industry consolidation has occurred on a lesser scale as well through mergers and acquisitions involving regional or smaller national or international competitors. Generally speaking, we believe that a marketplace with multiple supplier options for transport access is important to the long-term availability of competitive pricing, service quality, and carrier responsiveness. It is unclear at this time what the long-term impact of such consolidation will be, or whether it will continue at the same pace as it has in recent years; we cannot guarantee that we will continue to be able to obtain use of facilities or services in a timely manner or on terms acceptable and in quantities satisfactory to us from such suppliers.

We may occasionally have certain sales commitments to customers that extend beyond the commitments of our underlying suppliers.

Our financial results could be adversely affected if we were unable to purchase extended service from a supplier at a cost sufficiently low to maintain our margin for the remaining term of its commitment to a customer. While we have not encountered material price increases from suppliers with respect to continuation or renewal of services after expiration of initial contract terms, we cannot be certain that we would be able to obtain similar terms and conditions from suppliers. In most cases where we have faced any price increase from a supplier following contract expiration, we have been able to locate another supplier to provide the service at a similar or reduced future cost; however, our suppliers may not provide services at such cost levels in the future.

We may make purchase commitments to vendors for longer terms or in excess of the volumes committed by our underlying customers.

We attempt to match our purchases of network capacity from suppliers with the service commitments from our customers. However, from time to time, we have has obligations to our suppliers that exceed the duration of our related customer contracts or that are for capacity in excess of the amount for which we have customer commitments. This could arise based upon the terms and conditions available from our suppliers, from our expectation that we will be able to utilize the excess capacity, as a result of a breach of a customer’s commitment to us, or to support fixed elements of our network. Under any of these circumstances, we would incur the cost of the network capacity from our supplier without having corresponding revenue from our customers, which could result in a material and adverse impact on our operating results.

System disruptions, either in our network or in third party networks on which we depend, could cause delays or interruptions of our service, which could cause us to lose customers, or incur additional expenses.

Our customers depend on our ability to provide network availability with minimal interruption or degradation in services. The ability to provide this service depends in part on the networks of third party

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transport suppliers. The networks of transport suppliers may be interrupted as a result of various events, many of which they cannot control, including fire, human error, earthquakes and other natural disasters, power loss, telecommunications failures, terrorism, sabotage, vandalism, cyber-attacks, computer viruses or other infiltration by third parties or the financial distress or other events adversely affecting a supplier, such as bankruptcy or liquidation.

Although we have attempted to design our network services to minimize the possibility of service disruptions or other outages, in addition to risks associated with third party provider networks, our services may be disrupted by problems on our own systems, that affect our central offices, corporate headquarters, network operations centers, or network equipment. Our network, including our routers, may be vulnerable to unauthorized access, computer viruses, cyber-attacks, distributed denial of service (DDOS), and other security breaches. An attack on or security breach of our network could result in interruption or cessation of services, our inability to meet our service level commitments, and potentially compromise customer data transmitted over our network. There are certain locations through which a large amount of our Internet traffic passes. Examples are facilities in which we exchange traffic with other carriers, the facilities through which our intercontinental traffic passes, and certain of our network hub sites. If any of these facilities were destroyed or seriously damaged a significant amount of our network traffic could be disrupted. The continued threat of terrorist activity and other acts of war or hostility have had, and may continue to have, an adverse effect on business, financial and general economic conditions internationally. We are also susceptible to other catastrophic events such as major natural disasters, extreme weather, fire or similar events that could affect our headquarters, other offices, our network, infrastructure or equipment, which could adversely affect our business.

Disruptions or degradations in our service, could subject us to legal claims and liability for losses suffered by customers due to our inability to provide service. If our network failure rates are higher than permitted under the applicable customer contracts, we may incur significant expenses related to network outage credits, which would reduce our revenue and gross margin. In addition, customers may, under certain contracts, have the ability to terminate services in case of prolonged or severe service disruptions or other outages which would also adversely impact our results of operations. Our reputation could be harmed if we fail to provide a reasonably adequate level of network availability, and as a result we could find it more difficult to attract and retain customers.

If the products or services that we market or sell do not maintain market acceptance, our results of operations will be adversely affected.

Certain segments of the telecommunications industry are dependent on developing and marketing new products and services that respond to technological and competitive developments and changing customer needs. We cannot assure you that our products and services will gain or obtain increased market acceptance. Any significant delay or failure in developing new or enhanced technology, including new product and service offerings, could result in a loss of actual or potential market share and a decrease in revenue.

The communications market in which we operate is highly competitive; we could be forced to reduce prices, may lose customers to other providers that offer lower prices and have problems attracting new customers.

The communications industry is highly competitive and pricing for some of our key service offerings, such as our dedicated IP transport services, has been generally declining. If our costs of service, including the cost of leasing underlying facilities, do not decline in a similar fashion, we could experience significant margin compression, reduction of profitability and loss of business.

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If carrier and enterprise connectivity demand does not continue to expand, we may experience a shortfall in revenue or earnings or otherwise fail to meet public market expectations.

The growth of our business will be dependent, in part, upon the increased use of carrier and enterprise connectivity services and our ability to capture a higher proportion of this market. Increased usage of enterprise connectivity services depends on numerous factors, including:

Our long sales and service deployment cycles require us to incur substantial sales costs that may not result in related revenue.

Our business is characterized by long sales cycles between the time a potential customer is contacted and a customer contract is signed. The average sales cycle can be as little as two to six weeks for existing customers and three to six months or longer for new customers with complicated service requirements. Furthermore, once a customer contract is signed, there is typically an extended period of between 30 and 120 days before the customer actually begins to use the services, which is when we begin to realize revenue. As a result, we may invest a significant amount of time and effort in attempting to secure a customer, which investment may not result in near term, if any, revenue. Even if we enter into a contract, we will have incurred substantial sales-related expenses well before we recognize any related revenue. If the expenses associated with sales increase, if we are not successful in our sales efforts, or if we are unable to generate associated offsetting revenue in a timely manner, our operating results could be materially and adversely affected.  

Because much of our business is international, our financial results may be affected by foreign exchange rate fluctuations.

Approximately 43% of our revenue in 2013 came from countries outside of the United States. As such, other currencies, particularly the Euro and the British Pound Sterling can have an impact on our results (expressed in U.S. Dollars). Currency variations also contribute to variations in sales in impacted jurisdictions. Accordingly, fluctuations in foreign currency rates, most notably the strengthening of the dollar against the Euro and the Pound, could have a material impact on our revenue growth in future periods. In addition, currency variations can adversely affect margins on sales of our products in countries outside of the United States and margins on sales of products that include components obtained from suppliers located outside of the United States.

Because much of our business is international, we may be subject to local taxes, tariffs, statutory requirements, or other restrictions in foreign countries, which may reduce our profitability.

We are subject to various risks associated with conducting business worldwide. Revenue from our foreign subsidiaries, or other locations where we provide or procure services internationally, may be subject to additional taxes in some foreign jurisdictions. Additionally, some foreign jurisdictions may subject us to additional withholding tax requirements or the imposition of tariffs, exchange controls, or other restrictions on foreign earnings. We are also subject to foreign government employment standards, labor strikes and work stoppages. These risks and any other restrictions imposed on our foreign operations may increase our costs of business in those jurisdictions, which in turn may reduce our profitability.

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If our goodwill or amortizable intangible assets become impaired we may be required to record a significant charge to earnings.

Under generally accepted accounting principles, we review our amortizable intangible assets for impairment when events or changes in circumstances indicate the carrying value may not be recoverable. Goodwill is tested for impairment at least annually. Factors that may be considered a change in circumstances indicating that the carrying value of our goodwill or amortizable intangible assets may not be recoverable, include reduced future cash flow estimates, a decline in stock price and market capitalization, and slower growth rates in our industry. During the years ended December 31, 2013 and 2012, we recorded no impairment to goodwill and amortizable intangible assets. We may be required to record a significant charge to earnings in our financial statements during the period in which any impairment of our goodwill or amortizable intangible assets is determined, negatively impacting our results of operations.

The ability to implement and maintain our databases and management information systems is a critical business requirement, and if we cannot obtain or maintain accurate data or maintain these systems, we might be unable to cost-effectively provide solutions to our customers.

To be successful, we must increase and update information in our databases about network pricing, capacity and availability. Our ability to provide cost-effective network availability and access cost management depends upon the information we collect from our transport suppliers regarding their networks. These suppliers are not obligated to provide this information and could decide to stop providing it to us at any time. Moreover, we cannot be certain that the information that these suppliers share with us is accurate. If we cannot continue to maintain and expand the existing databases, we may be unable to increase revenue or to facilitate the supply of services in a cost-effective manner.

Furthermore, we are in the process of reviewing, integrating, and augmenting our management information systems to facilitate management of client orders, client service, billing, and financial applications. Our ability to manage our businesses could be materially adversely affected if we fail to successfully and promptly maintain and upgrade the existing management information systems.

If we are unable to protect our intellectual property rights, competitors may be able to use our technology or trademarks, which could weaken our competitive position.

We own certain proprietary programs, software and technology. However, we do not have any patented technology that would preclude competitors from replicating our business model; instead, we rely upon a combination of know-how, trade secret laws, contractual restrictions, and copyright, trademark and service mark laws to establish and protect our intellectual property. Our success will depend in part on our ability to maintain or obtain (as applicable) and enforce intellectual property rights for those assets, both in the United States and in other countries. Although our Americas operating company has registered some of its service marks in the United States, we have not otherwise applied for registration of any marks in any other jurisdiction. Instead, with the exception of the few registered service marks in the United States, we rely exclusively on common law trademark rights in the countries in which we operate.

We may file applications for patents, copyrights and trademarks as our management deems appropriate. We cannot assure you that these applications, if filed, will be approved or that we will have the financial and other resources necessary to enforce our proprietary rights against infringement by others. Additionally, we cannot assure you that any patent, trademark, or copyright obtained by us will not be challenged, invalidated, or circumvented, and the laws of certain foreign countries may not protect intellectual property rights to the same extent as do the laws of the United States or the member states of the European Union. Finally, although we intend to undertake reasonable measures to protect the proprietary assets of our combined operations, we cannot guarantee that we will be successful in all cases in protecting the trade secret status of certain significant intellectual property assets. If these assets should be misappropriated, if our intellectual property rights are otherwise infringed, or if a competitor should independently develop similar intellectual property, this could harm our ability to attract new clients, retain existing customers and generate revenue.

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Intellectual property and proprietary rights of others could prevent us from using necessary technology to provide our services or otherwise operate our business.

We utilize data and processing capabilities available through commercially available third-party software tools and databases to assist in the efficient analysis of network engineering and pricing options. Where such technology is held under patent or other intellectual property rights by third parties, we are required to negotiate license agreements in order to use that technology. In the future, we may not be able to negotiate such license agreements at acceptable prices or on acceptable terms. If an adequate substitute is not available on acceptable terms and at an acceptable price from another software licensor, we could be compelled to undertake additional efforts to obtain the relevant network and pricing data independently from other, disparate sources, which, if available at all, could involve significant time and expense and adversely affect our ability to deliver network services to customers in an efficient manner.

Furthermore, to the extent that we are subject to litigation regarding the ownership of our intellectual property or the licensing and use of others’ intellectual property, this litigation could:

Parties making claims of infringement may be able to obtain injunctive or other equitable relief that could effectively block our ability to provide our services and could cause us to pay substantial damages. In the event of a successful claim of infringement, we may need to obtain one or more licenses from third parties, which may not be available at a reasonable cost, if at all. The defense of any lawsuit could result in time-consuming and expensive litigation, regardless of the merits of such claims, and could also result in damages, license fees, royalty payments, and restrictions on our ability to provide our services, any of which could harm our business.

We continue to evaluate merger and acquisition opportunities and may purchase additional companies in the future, and the failure to integrate them successfully with our existing business may adversely affect our financial condition and results of operations.

We continue to explore merger and acquisition opportunities and we may face difficulties if we acquire other businesses in the future including:

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These difficulties could disrupt our ongoing business and increase our expenses. As of the date of this prospectus supplement, we have no agreement or memorandum of understanding to enter into any acquisition transaction.

In addition, our ability to complete acquisitions may depend, in part, on our ability to finance these acquisitions, including both the costs of the acquisition and the cost of the subsequent integration activities. Our ability may be constrained by our cash flow, the level of our indebtedness, restrictive covenants in the agreements governing our indebtedness, conditions in the securities and credit markets and other factors, most of which are generally beyond our control. If we proceed with one or more acquisitions in which the consideration consists of cash, we may use a substantial portion of our available cash to complete such acquisitions, thereby reducing our liquidity. If we finance one or more acquisitions with the proceeds of indebtedness, our interest expense and debt service requirements could increase materially. Thus, the financial impact of future acquisitions, including the costs to pursue acquisitions that do not ultimately close, could materially affect our business and could cause substantial fluctuations in our quarterly and yearly operating results.

Our efforts to develop new service offerings may not be successful, in which case our revenue may not grow as we anticipate or may decline.

The market for telecommunications services is characterized by rapid change, as new technologies are developed and introduced, often rendering established technologies obsolete. For our business to remain competitive, we must continually update our service offerings to make new technologies available to our customers and prospects. To do so, we may have to expend significant management and sales resources, which may increase our operating costs. The success of our potential new service offerings is uncertain and would depend on a number of factors, including the acceptance by end-user customers of the telecommunications technologies which would underlie these new service offerings, the compatibility of these technologies with existing customer information technology systems and processes, the compatibility of these technologies with our then-existing systems and processes, and our ability to find third-party vendors that would be willing to provide these new technologies to us for delivery to our users. If we are unsuccessful in developing and selling new service offerings, our revenue may not grow as we anticipate, or may decline.

If we do not continue to train, manage and retain employees, clients may reduce purchases of services.

Our employees are responsible for providing clients with technical and operational support, and for identifying and developing opportunities to provide additional services to existing clients. In order to perform these activities, our employees must have expertise in areas such as telecommunications network technologies, network design, network implementation and network management, including the ability to integrate services offered by multiple telecommunications carriers. They must also accept and incorporate training on our systems and databases developed to support our operations and business model. Employees with this level of expertise tend to be in high demand in the telecommunications industry, which may make it more difficult for us to attract and retain qualified employees. If we fail to train, manage, and retain our employees, we may be limited in our ability to gain more business from existing clients, and we may be unable to obtain or maintain current information regarding our clients’ and suppliers’ communications networks, which could limit our ability to provide future services.

The regulatory framework under which we operate could require substantial time and resources for compliance, which could make it difficult and costly for us to operate the businesses.

In providing certain interstate and international telecommunications services, we must comply, or cause our customers or carriers to comply, with applicable telecommunications laws and regulations prescribed by the FCC and applicable foreign regulatory authorities. In offering services on an intrastate basis, we may also be subject to state laws and to regulation by state public utility commissions. Our international services may also be subject to regulation by foreign authorities and, in some markets, multinational authorities, such as the European Union.

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The costs of compliance with these regulations, including legal, operational and administrative expenses, may be substantial. In addition, delays in receiving or failure to obtain required regulatory approvals or the enactment of new or adverse legislation, regulations or regulatory requirements may have a material adverse effect on our financial condition, results of operations and cash flow.

If we fail to obtain required authorizations from the FCC or other applicable authorities, or if we are found to have failed to comply, or are alleged to have failed to comply, with the rules of the FCC or other authorities, our right to offer certain services could be challenged and/or fines or other penalties could be imposed on us. Any such challenges or fines could be substantial and could cause us to incur substantial legal and administrative expenses as well; these costs in the forms of fines, penalties, and legal and administrative expenses could have a material adverse impact, on our business and operations. Furthermore, we are dependent in certain cases on the services other carriers provide, and therefore on other carriers’ abilities to retain their respective licenses in the regions of the world in which they operate. We are also dependent, in some circumstances, on our customers’ abilities to obtain and retain the necessary licenses. The failure of a customer or carrier to obtain or retain any necessary license could have an adverse effect on our ability to conduct operations.

Future changes in regulatory requirements, new interpretations of existing regulatory requirements, or determinations that we violated existing regulatory requirements may impair our ability to provide services, result in financial losses or otherwise reduce our profitability.

Many of the laws and regulations that apply to providers of telecommunications services are subject to frequent changes and different interpretations and may vary between jurisdictions. Changes to existing legislation or regulations in particular markets may limit the opportunities that are available to enter into markets, may increase the legal, administrative, or operational costs of operating in those markets, or may constrain other activities, including our ability to complete subsequent acquisitions, or purchase services or products, in ways that we cannot anticipate. Because we purchase telecommunications services from other carriers, our costs and manner of doing business can also be adversely affected by changes in regulatory policies affecting these other carriers.

In addition, any determination that we, including companies that we have acquired, have violated applicable regulatory requirements could result in material fines, penalties, forfeitures, interest or retroactive assessments. For example, a determination that we have not paid all required universal service fund contributions could result in substantial retroactive assessment of universal service fund contributions, together with applicable interest, penalties, fines or forfeitures.

We depend on key personnel to manage our businesses effectively in a rapidly changing market, and our ability to generate revenue will suffer if we are unable to retain key personnel and hire additional personnel.

The future success, strategic development and execution of our business will depend upon the continued services of our executive officers and other key sales, marketing and support personnel. We do not maintain “key person” life insurance policies with respect to any of our employees, nor are we certain if any such policies will be obtained or maintained in the future. We may need to hire additional personnel in the future and we believe the success of the combined business depends, in large part, upon our ability to attract and retain key employees. The loss of the services of any key employees, the inability to attract or retain qualified personnel in the future, or delays in hiring required personnel could limit our ability to generate revenue and to operate our business.

Our business and operations are growing rapidly and we may not be able to efficiently manage our growth.

We have rapidly grown our company through network expansion and obtaining new customers through our sales efforts. Our expansion places significant strains on our management, operational and financial infrastructure. Our ability to manage our growth will be particularly dependent upon our ability to:

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If we fail to implement these measures successfully, our ability to manage our growth will be impaired.

Interruption or failure of our information technology and communications systems could hurt our ability to effectively provide our products and services, which could damage our reputation and harm our operating results.

The availability of our products and services depends on the continuing operation of our information technology and communications systems. Our systems are vulnerable to damage or interruption from earthquakes, terrorist attacks, floods, fires, power loss, telecommunications failures, computer viruses, computer denial of service attacks or other attempts to harm our systems. Some of our systems are not fully redundant and our disaster recovery planning cannot account for all eventualities. The occurrence of a natural disaster, a decision to close a facility we are using without adequate notice for financial reasons, or other unanticipated problems at our data centers could result in lengthy interruptions in our service.

Risks Relating to Our Indebtedness

Our failure to comply with covenants in our loan agreements could result in our indebtedness being immediately due and payable and the loss of our assets.

Pursuant to the terms of our loan agreements, we have pledged substantially all of our assets to the lenders as security for our payment obligations under the loan agreements. If we fail to pay any of our indebtedness under the loan agreements when due, or if we breach any of the other covenants in the loan agreements, it may result in one or more events of default. An event of default under our loan agreements would permit the lenders to declare all amounts owing to be immediately due and payable and, if we were unable to repay any indebtedness owed, the lenders could proceed against the collateral securing that indebtedness.

Covenants in our loan agreements and outstanding notes, and in any future debt agreements, may restrict our future operations.

The loan agreements related to our outstanding senior and mezzanine indebtedness impose financial restrictions that limit our discretion on some business matters, which could make it more difficult for us to expand our business, finance our operations and engage in other business activities that may be in our interest. These restrictions include compliance with, or maintenance of, certain financial tests and ratios and restrictions that limit our ability and that of our subsidiaries to, among other things:

Any additional indebtedness we may incur in the future may subject us to similar or even more restrictive conditions.

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Our substantial level of indebtedness and debt service obligations could impair our financial condition, hinder our growth and put us at a competitive disadvantage.

As of December 31, 2013, our indebtedness was substantial in comparison to our available cash and our cash provided by operations. Our substantial level of indebtedness could have important consequences for our business, results of operations and financial condition. For example, a high level of indebtedness could, among other things:

Risks Related to our Common Stock and the Securities Markets

Because we do not currently intend to pay dividends on our common stock, stockholders will benefit from an investment in our common stock only if it appreciates in value.

We do not currently anticipate paying any dividends on shares of our common stock. Any determination to pay dividends in the future will be made by our Board of Directors and will depend upon results of operations, financial conditions, contractual restrictions, restrictions imposed by applicable law and other factors our Board of Directors deems relevant. Accordingly, realization of a gain on stockholders’ investments will depend on the appreciation of the price of our common stock. There is no guarantee that our common stock will appreciate in value or even maintain the price at which stockholders purchased their shares.

We may issue a substantial number of shares of our common stock in the future, and stockholders may be adversely affected by the issuance of those shares.

As of April 30, 2014, we had outstanding warrants to purchase approximately 2.3 million shares of our common stock at a weighted-average exercise price equal to $2.34 per share, and we also had stock options outstanding to purchase approximately 1.6 million shares of our common stock at a weighted-average exercise price equal to $4.43 per share. We may issue additional stock options for compensation purposes in the future under our existing stock option plans or any future stock option plans that we may adopt. In addition to these warrants and options, we may raise additional capital from time to time in the future by issuing shares of our common stock or securities convertible into shares of our common stock. The registration statement of which this prospectus supplement is a part provides for the potential issuance of common stock, preferred stock, warrants, debt securities and units up to an aggregate amount of $200,000,000. Following this offering at the public

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offering price of $7.75 per share we can issue up to $176,750,000 (and if the underwriters exercise their option to purchase additional shares in full, $173,262,500) in securities pursuant to such registration statement. In addition, from time to time in the future we may issue shares of our common stock or securities convertible into common stock pursuant to additional registration statements or exemptions from registration under the Securities Act. If, and to the extent, any additional shares of common stock are sold in the public market, our stockholders, including investors who purchase shares of common stock in this offering, may experience dilution to their ownership interests in the Company. In addition, sales of substantial amounts of our common stock in the public market, or the perception that those sales will occur, could cause the market price of our common stock to decline or be depressed.

The concentration of our capital stock ownership will likely limit a stockholder’s ability to influence corporate matters, and could discourage a takeover that stockholders may consider favorable and make it more difficult for a stockholder to elect directors of its choosing.

H. Brian Thompson, our Executive Chairman of the Board of Directors, and Universal Telecommunications, Inc., his own private equity investment and advisory firm, owned 6,746,171 shares of our common stock at April 14, 2014. Based on the number of shares of our common stock outstanding on April 14, 2014, Mr. Thompson and Universal Telecommunications, Inc. would beneficially own approximately 28% of our common stock. Based on public filings with the SEC made by J. Carlo Cannell, we believe that, as of December 31, 2013, funds associated with Cannell Capital LLC owned 3,371,880 shares of our common stock. Based on the number of shares of our common stock outstanding on April 14, 2014, these funds would beneficially own approximately 14% of our common stock. In addition, as of April 14, 2014, our executive officers, directors and affiliated entities, excluding H. Brian Thompson and Universal Telecommunications, Inc., together beneficially owned common stock, without taking into account their unexercised options, representing approximately 13% of our common stock. As a result, these stockholders have the ability to exert significant control over matters that require approval by our stockholders, including the election of directors and approval of significant corporate transactions. The interests of these stockholders might conflict with your interests as a holder of our securities, and it may cause us to pursue transactions that, in their judgment, could enhance their equity investments, even though such transactions may involve significant risks to you as a security holder. The large concentration of ownership in a small group of stockholders might also have the effect of delaying or preventing a change of control of GTT that other stockholders may view as beneficial.

It may be difficult for you to resell shares of our common stock if an active market for our common stock does not develop.

Our common stock has only recently been listed on the NYSE MKT, and prior to this listing the common stock was thinly traded on the OTC Markets. If a liquid market for the common stock does not develop on the NYSE MKT, then, in addition to the concentrated ownership of our capital stock, this may further impair your ability to sell your shares when you want to do so and could depress our stock price. As a result, you may find it difficult to dispose of, or to obtain accurate quotations of the price of, our securities because smaller quantities of shares could be bought and sold, transactions could be delayed, and security analyst and news coverage of the Company may be limited. These factors could result in lower prices and larger spreads in the bid and ask prices for our shares.

Our charter documents, as well as certain portions of Delaware law, contain anti-takeover provisions that could discourage or prevent a third-party acquisition of our common stock, even if an acquisition would be beneficial to our stockholders.

Some provisions in our second restated certificate of incorporation and of our amended and restated by-laws, as well as some provisions of Delaware law, could have the effect of discouraging, delaying or preventing a third party from attempting to acquire us, even if doing so would be beneficial to stockholders, including

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transactions in which investors might otherwise receive a premium for their shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock. These provisions could also prevent or frustrate attempts by our stockholders to replace or remove our management. These provisions include:

In addition, we have entered into employment agreements with most of our executive officers which, among other things, include provisions for severance payments upon a change in control or circumstances after a change in control.

Risks Related to this Offering

We may allocate the net proceeds from this offering in ways that you and other stockholders may not approve.

We intend to use the net proceeds from this offering for general corporate purposes, including, among other things, working capital requirements and possible future acquisitions. In general, our management will have broad discretion in the application of the net proceeds from this offering and could spend the net proceeds in ways that do not necessarily improve our operating results or enhance the value of our common stock.

If you purchase the common stock sold in this offering you will experience immediate and substantial dilution in your investment. You will experience further dilution if we issue additional equity securities in future fundraising transactions.

Since the price per share of our common stock being offered is substantially higher than the net tangible book value per share of our common stock, you will suffer you will suffer immediate and substantial dilution with respect to the net tangible book value of the common stock you purchase in this offering. See the section titled “Dilution” in this prospectus supplement for a more detailed discussion of the dilution you will incur if you purchase common stock in this offering.

We have a significant number of warrants and stock options outstanding. To the extent that these warrants or options are exercised, investors purchasing our common stock in this offering may experience further dilution. In addition, if we issue additional common stock, or securities convertible into or exchangeable or exercisable for common stock , our stockholders, including investors who purchase shares of common stock in this offering, could experience additional dilution, and any such issuances may result in downward pressure on the price of our common stock.

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RISK FACTORS

Investing in our securities involves risk. Before making an investment decision, you should carefully consider the risks and other information that we include or incorporate by reference into this prospectus and any prospectus supplement. In particular, you should consider the risk factors under the heading “Risk Factors” included in our most recent Annual Report on Form 10-K, as revised or supplemented by our subsequent filings with the Securities and Exchange Commission, or the “SEC”, which are incorporated by reference into this prospectus. These risk factors may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future or by a prospectus supplement relating to a particular offering of our securities. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not currently known to us or that we currently deem immaterial may also affect our business operations. Additional risk factors may be included in a prospectus supplement relating to a particular offering of securities. If any of the risks or uncertainties described in our SEC filings or any prospectus supplement or any additional risks and uncertainties actually occur, our business, financial condition and results of operations could be materially and adversely affected. In that case, the trading price of our securities could decline and you might lose all or part of your investment.

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ABOUT THIS PROSPECTUS

In this prospectus, unless otherwise specified or the context otherwise requires, “GTT,” “we,” “us” and “our,” “our Company” or the “Company” refer to GTT Communications, Inc. and its consolidated subsidiaries. In addition, unless the context requires otherwise, reference to the “Board” refers to the Board of Directors of GTT Communications, Inc.

This prospectus is part of a registration statement that we filed with the SEC utilizing a “shelf” registration or continuous offering process. Under this shelf registration or continuous offering process, we or the selling stockholders may, from time to time, offer and sell securities pursuant to this prospectus. This prospectus provides you with a general description of the securities we may offer. Each time we sell our securities under this shelf registration or continuous offering process, we or the selling stockholders will provide a prospectus supplement that will contain specific information about the terms of that offering and the specific securities being offered. A prospectus supplement may include a discussion of any risk factors in addition to those included or incorporated herein under the heading “Risk Factors” or other special considerations applicable to those securities or to us or the selling stockholders. A prospectus supplement may also add, update or change information in this prospectus. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement, you must rely on the information in the prospectus supplement. You should read carefully both this prospectus and any prospectus supplement, together with additional information described below under “Where You Can Find More Information” before you invest in our securities.

You should rely only on the information contained or incorporated by reference in this prospectus, any prospectus supplement that is prepared by us or on our behalf or that is otherwise authorized by us. We have not authorized any other person to provide you with additional or different information. If anyone provides you with additional, different or inconsistent information, you should not rely on it. This prospectus and the accompanying prospectus supplement is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus and the accompanying prospectus supplement is accurate on any date subsequent to the date set forth on the front of the document or that any information that we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference. Our business, financial condition, results of operation and prospects may have changed since those dates.

We or the selling stockholders may sell securities to underwriters who will sell the securities to the public on terms fixed at the time of sale. In addition, the securities may be sold by us or the selling stockholders directly to purchasers or through dealers or agents designated from time to time. If we or the selling stockholders, directly or through agents, solicit offers to purchase the securities, we and the selling stockholders, as the case may be, reserve the sole right to accept and, together with any agents, to reject, in whole or in part, any of those offers. Any prospectus supplement will contain the names of the underwriters, dealers or agents, if any, together with the terms of offering, the compensation of those underwriters and the net proceeds to us and the selling stockholders. Any underwriters, dealers or agents participating in the offering may be deemed “underwriters” within the meaning of the United States Securities Act of 1933, as amended, which we refer to as the “Securities Act”.

WHERE YOU CAN FIND MORE INFORMATION

We file periodic reports, proxy statements and other information relating to our business, financial and other matters with the SEC under the Securities Exchange Act of 1934, as amended, which we refer to as the “Exchange Act”. Our filings are available to the public over the Internet at the SEC’s web site at http://www.sec.gov. You may also read and copy any document we file with the SEC at, and obtain a copy of any such document by mail from, the SEC’s public reference room located at 100 F Street, N.E., Washington, D.C. 20549, at prescribed charges. Please call the SEC at 1-800-SEC-0330 for further information on the public reference room and its charges.

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We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to our securities described in this prospectus. References to the “registration statement” or the “registration statement of which this prospectus is a part” mean the original registration statement and all amendments, including all schedules and exhibits. This prospectus does, and any prospectus supplement will, not contain all of the information in the registration statement because we have omitted parts of the registration statement in accordance with the rules of the SEC. Please refer to the registration statement for any information in the registration statement that is not contained in this prospectus or a prospectus supplement. The registration statement is available to the public over the Internet at the SEC’s web site described above and can be read and copied at the locations described above.

Each statement made in this prospectus or any prospectus supplement concerning a document filed as an exhibit to the registration statement is qualified in its entirety by reference to that exhibit for a complete description of its provisions.

We make available, free of charge, on or through our web site, copies of our proxy statements, our annual reports on Form 10-K, our quarterly reports on Form 10-Q, our current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file them with or furnish them to the SEC. We maintain a web site at http://www.gtt.net. The information contained on our web site is not part of this prospectus, any prospectus supplement or the registration statement.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information in other documents that we file with it, 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 later information that we file with the SEC will automatically update and, if applicable, supersede information contained in documents filed earlier with the SEC or contained in this prospectus or a prospectus supplement.

We specifically incorporate by reference into this prospectus the documents listed below which have previously been filed with the SEC:

We incorporate by reference (1) any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act following the date of this prospectus and prior to the termination of the offering covered by this prospectus and any prospectus supplement and (2) any filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of the registration statement of which this prospectus is a part and prior to the effectiveness of such registration statement, in each case excluding any information deemed furnished and not filed with the SEC.

Notwithstanding the foregoing, unless specifically stated to the contrary, information that we furnish (and that is not deemed “filed” with the SEC) under Items 2.02 and 7.01 of any Current Report on Form 8-K, including the related exhibits under Item 9.01, is not incorporated by reference into this prospectus, the registration statement of which this prospectus is a part, or any prospectus supplement.

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Any statement contained in a document that is incorporated by reference will be modified or superseded for all purposes to the extent that a statement contained in this prospectus or any accompanying prospectus supplement, or in any other document that is subsequently filed with the SEC and incorporated into this prospectus by reference, modifies or is contrary to that previous statement. Any statement so modified or superseded will not be deemed a part of this prospectus or any accompanying prospectus supplement, except as so modified or superseded. Since information that we later file with the SEC will update and supersede previously incorporated information, you should look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus or any accompanying prospectus supplement or in any documents previously incorporated by reference have been modified or superseded.

We make available copies of the documents incorporated by reference in this prospectus to each person, including any beneficial owner, to whom a prospectus is delivered, without charge, upon written or oral request. Such requests should be directed to:

GTT Communications, Inc.

8484 Westpark Drive, Suite 720

McLean, Virginia 22102

Attention: Investor Relations

Telephone: (703) 442-5500

These filings can also be obtained through the SEC as described above or, with respect to certain of these documents, at our website at www.gtt.net. Except for the documents described above, information on our website is not incorporated by reference into this prospectus and you should not consider information contained on our website to be part of this prospectus or any prospectus supplement.

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CAUTIONARY STATEMENT ON FORWARD-LOOKING INFORMATION

This prospectus, including documents we incorporate by reference into this prospectus, and any applicable prospectus supplement contains forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. These statements relate to future events or our future financial performance. In some cases, you can identify forward-looking statements by forward-looking words such as “may,” “will,” “should,” “could,” “expect,” “plan,” “anticipate,” “believe,” “intend,” “estimate,” “predict,” “potential” or “continue,” the negative of such terms or other comparable terminology, although not all forward-looking statements contain these words. These statements are only predictions. Actual events or results may differ materially.

Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance or achievements. Moreover, neither we, nor any other person, assume responsibility for the accuracy and completeness of the forward-looking statements. We are under no obligation to update any of the forward-looking statements after the date of this prospectus and any applicable prospectus supplement to conform such statements to actual results or to changes in our expectations.

Such forward-looking statements are and will be subject to many risks, uncertainties and factors relating to our operations and the business environment that may cause our actual results to be materially different from any future results, express or implied, by such forward-looking statements. You are also urged to carefully review and consider the various disclosures made by us that attempt to advise interested parties of the factors that affect our business, including without limitation the disclosures made in our Annual Report on Form 10-K for the year ended December 31, 2013 under the caption “Risk Factors.” Factors that could cause actual results to differ from those contained in the forward-looking statements include, but are not limited to:

In light of the significant risks and uncertainties to which our forward-looking statements are subject, you should not place undue reliance on or regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified timeframe, or at all. These forward-looking statements represent our estimates and assumptions only as of the date of this prospectus regardless of the time of delivery of this prospectus or any sale of our securities and, except as required by law, we undertake no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise after the date of this prospectus. For all forward-looking statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

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ABOUT GTT

We operate a global Tier 1 IP network with one of the most interconnected Ethernet service platforms around the world. We provide highly reliable, scalable and secure cloud networking services. As of December 31, 2013, our customer base was comprised of over 2,000 businesses, and we provide services in over 100 countries. We have designed, delivered, and subsequently managed services in all six populated continents around the world.

We have deployed network assets in North America, Europe and Asia to provide Dedicated Internet Access, IP Transit and Ethernet Transport services. We have approximately 200 Points of Presence (PoPs) and network connectivity in all major U.S. cities and European cities, and we have established Ethernet hubs with various carriers and multiple connections to other Tier 1 IP providers. The GTT backbone network is built using a multi-layer design developed to offer the highest level of performance and reliability. Our private optical long-haul network provides the foundation for a Layer 2 Ethernet-over-MPLS mesh between core backbone routers in each city. This same infrastructure also provides dedicated data transport services to customers in GTT’s backbone cities. Additionally, we have over 800 supplier relationships worldwide from which we source bandwidth and other services and combine our own network assets to meet our customers’ requirements. Through our extensive supplier relationships, our customers have access to an array of service providers without having to manage multiple contracts.

Our service expansion is largely customer-driven. Because our markets are highly competitive, we believe that personal relationships and quality of service delivery remain important in winning new and repeat customer business. We sell our services largely through a direct sales force located across the globe, as well as through agent channel relationships, with a principal concentration in the United States and the United Kingdom.

Our executive offices are located at 8484 Westpark Drive, Suite 720, McLean, Virginia 22102, and our telephone number is (703) 442-5500. We maintain an Internet website at www.gtt.net. Information contained on, or that can be accessed through, our website is not part of this prospectus.