This Amendment No. 4 to the Registration Statement on Form S-1 is being filed solely to include the artwork that will appear on the inside cover of the Prospectus. No other changes have been made.

You should rely only on the information contained in this prospectus. We have not, the selling stockholders have not and the underwriters have not, authorized anyone to provide you with additional information or information different from that contained in this prospectus. We and the selling stockholders are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The information contained in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or of any sale of shares of our common stock.

PowerBuoy^® is a registered trademark of Ocean Power Technologies, Inc. The Ocean Power Technologies logo, CellBuoy^tm, Talk on Water^tm and Making Waves in Power^sm are trademarks or service marks of Ocean Power Technologies, Inc. All other trademarks appearing in this prospectus are the property of their respective holders.

Investing in our common stock involves a high degree of risk. You should carefully consider the risks described below with all of the other information included in this prospectus before deciding to invest in our common stock. If any of the following risks actually occur, they may materially harm our business and our financial condition and results of operations. In this event, the market price of our common stock could decline and you could lose part or all of your investment.

We have incurred net losses since we began operations in 1994, including net losses of $2.8 million in fiscal 2004, $0.4 million in fiscal 2005 and $7.1 million in fiscal 2006. As of January 31, 2007, we had an accumulated deficit of approximately $34.1 million. These losses have resulted primarily from costs incurred in our research and development programs and from our selling, general and administrative costs. We expect to increase our operating expenses significantly as we continue to expand our infrastructure, research and development programs and commercialization activities. As a result, we will need to generate significant revenues to cover these costs and achieve profitability.

We have entered into an agreement for the first phase of construction of a wave power station off the coast of Santoña, Spain, as well as an operations and maintenance contract for the equipment to be installed in this first phase. Under both contracts our potential profitability is limited. Under the construction contract, our revenues are limited to reimbursement for our construction costs without any mark-up and we are required to bear the first €0.5 million of any cost overruns. Under the operations and maintenance contract, we are paid a fixed fee for scheduled maintenance, the profits on which are required to be refunded to cover any unscheduled maintenance fees we receive during the term of the agreement.

We do not know whether or when we will become profitable because of the significant uncertainties with respect to our ability to successfully commercialize our PowerBuoy^® systems in the emerging renewable energy market. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. If we are unable to achieve and then maintain profitability, the market value of our common stock may decline.

Wave energy technology is at an early stage of development, and the extent to which wave energy power generation will be commercially viable is uncertain. Many factors may affect the commercial acceptance of wave energy technology, including the following:

If wave energy technology does not gain broad commercial acceptance, our business will be materially harmed and we may need to curtail or cease operations.

Even if wave energy technology achieves broad commercial acceptance, our PowerBuoy systems may not prove to be a commercially viable technology for generating electricity from ocean waves. We have invested a significant portion of our time and financial resources since our inception in the development of our PowerBuoy systems. To date, we have not yet manufactured and deployed any PowerBuoy systems for commercial use. As we begin to manufacture, market, sell and deploy our PowerBuoy systems in greater quantities, unforeseen hurdles may be encountered that would limit the commercial viability of our PowerBuoy systems, including unanticipated manufacturing, deployment, operating, maintenance and other costs. Our target customers and we may also encounter technical obstacles to deploying, operating and maintaining PowerBuoy systems in quantities necessary to generate competitively-priced electricity.

If demand for our PowerBuoy systems fails to develop sufficiently, we may be unable to grow our business or generate sufficient revenues to achieve and then sustain profitability. In addition, demand for PowerBuoy systems in our presently targeted markets, including coastal North America, the west coast of Europe, the coasts of Australia and the east coast of Japan, may not develop or may develop to a lesser extent than we anticipate.

If we are not successful in commercializing our PowerBuoy system, or are significantly delayed in doing so, our business, financial condition and results of operations could be adversely affected.

Federal, state and local governmental bodies in many countries, most notably France, Spain, the United Kingdom, Australia, Japan and the United States, have provided subsidies in the form of tariff subsidies, rebates, tax credits and other incentives to utilities, power generators and distributors using renewable energy. However, these incentives and subsidies generally decline over time, and many incentive and subsidy programs have specific expiration dates. Moreover, because the market for electricity generated from wave energy is at an early stage of development, some of the programs may not include wave energy as a renewable energy source eligible for the incentives and subsidies.

Currently, the cost of electricity generated from wave energy, without the benefit of subsidies or other economic incentives, substantially exceeds the price of electricity in most significant markets in the world. As a result, the near-term growth of the market for our utility PowerBuoy systems, which are designed to feed electricity into a local or regional power grid, depends significantly on the availability and size of government incentives and subsidies for wave energy. As renewable energy becomes more of a competitive threat to conventional energy providers, companies active in the conventional energy business may increase their lobbying efforts in order to encourage governments to stop providing subsidies for renewable energy, including wave energy. We cannot predict the level of any such efforts, or how governments may react to such efforts. The reduction, elimination or expiration of government incentives and subsidies, or the exclusion of wave energy technology from those incentives and subsidies, may result in the diminished competitiveness of wave energy relative to conventional and non-wave energy renewable sources of energy. Such diminished competitiveness could materially and adversely affect the growth of the wave energy industry, which could in turn adversely affect our business, financial condition and results of operations.

In 2000, we entered into an agreement with Woodside Sustainable Energy Solutions Pty. Ltd., or Woodside, under which we received $0.6 million in exchange for granting Woodside an option to purchase, at a 30% discount from the then-prevailing market rate, up to 500,000 metric tons of carbon emission credits we generate during the years 2008 through 2012. However, if by December 31, 2012 we do not become entitled under applicable laws to the full amount of emission credits covered by the option, we are obligated to return the option fee of $0.6 million, less the aggregate discount on any emission credits sold to Woodside prior to such date. If we receive emission credits under applicable laws and fail to sell to Woodside the credits up to the full amount of emission credits covered by the option, Woodside is entitled to liquidated damages equal to

Our product development costs primarily relate to our efforts to increase the maximum rated output of our current 40kW utility PowerBuoy system in successive stages to 500kW in 2010. Our product development costs were $4.1 million in the nine months ended January 31, 2007 as compared to $2.6 million in the same period in 2006, and were $4.2 million in fiscal 2006 as compared to $0.9 million in fiscal 2005 and $0.3 million in fiscal 2004. We anticipate that our product development costs related to the planned increase in the output of our utility PowerBuoy system will increase significantly over the next several years.

We have constructed and plan to construct in the future demonstration wave power stations to establish the feasibility of wave energy technology and to encourage the market adoption of our wave power stations. Demonstration wave power stations allow potential customers to see first-hand the viability of wave energy technology as a source of electricity. We incur significant costs in constructing and maintaining these demonstration wave power stations, and we may generate little or no direct revenue from them.

We began developing and testing wave energy technology nearly 10 years ago. However, to date we have only manufactured eight PowerBuoy systems for use in testing and development. The longest continuous in-ocean deployment of our PowerBuoy system has been for 12 months. As a result, our PowerBuoy systems do not have a sufficient operating history to confirm how they will perform over their estimated 30-year useful life. Our technology has not been deployed commercially and we have not yet demonstrated that our engineering and test results can be duplicated in commercial production. We have conducted and plan to continue to conduct practical testing of our PowerBuoy system. If our PowerBuoy system ultimately proves ineffective or unfeasible, we may not be able to engage in commercial production of our products or we may become liable to our customers for quantities we are obligated but are unable to produce. If our PowerBuoy systems perform below expectations, we could lose customers and face substantial repair and replacement expense which could in turn adversely affect our business, financial condition and results of operations.

One of our goals is to increase the maximum rated output of our utility PowerBuoy system, which is currently 40kW, to 150kW in 2007, then to 250kW in 2008 and ultimately to 500kW in 2010. Our success in meeting this objective depends on our ability to significantly increase the power output of our PowerBuoy system in a cost-effective and timely manner and our ability to overcome the engineering and deployment hurdles that we face, including developing design and construction techniques that will enable the larger PowerBuoy systems to be deployed cost effectively and without damage, and developing adjustments to the mooring system to account for the larger sized PowerBuoy systems. We have experienced delays in the development and deployment of our PowerBuoy system in the past, and could experience similar delays or other difficulties in the future. If we cannot increase the power output of the PowerBuoy system, or if it takes us longer to do so than we anticipate, we may be unable to expand our business, maintain our competitive position, satisfy our contractual obligations or become profitable. In addition, if the cost associated with these development efforts exceeds our projections, our results of operations will be adversely affected.

Unless we reach full commercial scale, which we estimate to be manufacturing levels of at least 300 units of 500kW PowerBuoy systems per year, we may not be able to offer an electricity solution that competes on a

We have not yet deployed a wave power station consisting of an array of two or more PowerBuoy systems. Our success in developing and deploying a wave power station consisting of an array of two or more PowerBuoy systems is contingent upon, among other things, receipt of required governmental permits, obtaining adequate financing, successful array design implementation and finally, successful deployment and connection of the PowerBuoy systems.

We have not conducted ocean testing or otherwise installed in the ocean a multiple-system wave power station. In particular, unlike single-system wave power stations, multiple-system wave power stations require use of an underwater substation to connect the cables from, and collect the electricity generated by, each PowerBuoy system in the array. If our underwater substation does not work as we anticipate, we will need to design an alternative system, which could delay our business plans. In addition, unanticipated issues may arise with the logistics and mechanics of deploying and maintaining multiple PowerBuoy systems at a single site and the additional equipment associated with these multiple-system wave power stations.

We may be unsuccessful in accomplishing any of these tasks or doing so on a timely basis. The development and deployment of an array of PowerBuoy systems may require us to incur significant expenses for preliminary engineering, permitting and legal and other expenses before we can determine whether a project is feasible, economically attractive or capable of being financed.

We will need to build larger buoys in order to increase the output of our current PowerBuoy systems. The larger buoys will be more difficult than our current buoys to deploy cost effectively and without damage. Our current deployment methodologies, including transportation to the installation site and the mooring of the PowerBuoy systems, will need to be revised for PowerBuoy systems with greater output. If we cannot develop cost effective methodologies for deployment of the larger PowerBuoy systems, or if it takes us longer to do so than we anticipate, we may not be able to deploy such systems in the time we anticipate or at all. Therefore, even if we succeed in increasing the output of our PowerBuoy systems above 40kW, if we are unable to deploy these larger PowerBuoy systems or encounter problems in doing so, we may be unable to expand our business, maintain our competitive position, satisfy our contractual obligations or become profitable.

In July 2006, we entered into an agreement for the first phase of the construction of a wave power station off the coast of Santoña, Spain, with our customer, Iberdrola Energias Marinas de Cantabria, S.A., or Iberdrola Cantabria. We refer to this agreement as the Spain construction agreement. Iberdrola Cantabria was formed by affiliates of Iberdrola and Total, two Spanish governmental agencies and us for the purpose of constructing and operating a wave power station off the coast of Spain. Under the Spain construction agreement, we have agreed to manufacture and deploy no later than December 31, 2009 one 40kW PowerBuoy system and the ocean-based substation and infrastructure required to connect nine additional 150kW PowerBuoy systems that together are contemplated to constitute a 1.39MW wave power station. Under the terms of the agreement, our revenues are limited to reimbursement for our construction costs without any mark-up. In addition, we are required to bear the first €0.5 million of any cost overruns. As of January 31, 2007, we had recognized an anticipated loss of $0.5 million under the Spain construction agreement.

In addition, because the Spain construction agreement does not cover the terms for deployment of all ten PowerBuoy units, we will need to enter into a subsequent contract with Iberdrola Cantabria before we complete construction of the full wave power station. If we are unable to successfully manufacture all ten PowerBuoy units or meet the terms of the Spain construction agreement, or if we are not able to successfully

Under our agreement with affiliates of Iberdrola and Total to study and assess the feasibility of a wave power station off the coast of France, either of Iberdrola or Total may withdraw. In addition, in order to proceed with development of the France wave power station, all three parties must conclude that development is feasible. If we proceed, Iberdrola, Total and we will form a new company for the purpose of constructing and operating the wave power station. If either Iberdrola or Total withdraws or does not agree that development of the wave power station is feasible, we may not be able to proceed with development of the wave power station. In addition, if we withdraw from the France project, we will remain obligated to supply and install equipment and provide the new company with assistance and information so that a new company can operate the wave power station.

If either of the Spain or France projects were cancelled or otherwise interrupted, it would adversely affect our business, financial condition and results of operations.

An important element of our business strategy is to maximize our revenue opportunities with our existing and future customers by seeking to enter into operations and maintenance contracts with them under which we would be paid fees for operating and maintaining wave power stations that they have purchased from us. Even if customers purchase our PowerBuoy systems, they may not enter into operations and maintenance contracts with us. We may not be able to negotiate operations and maintenance contracts that provide us with any profit opportunities. Even if we successfully negotiate and enter into such operations and maintenance contracts, our customers may terminate them prematurely or they may not be profitable for a variety of reasons, including the presence of unforeseen hurdles or costs. In addition, our inability to perform adequately under such operations and maintenance contracts could impair our efforts to successfully market the PowerBuoy systems. Any one of these outcomes could have a material adverse effect on our business, financial condition and results of operations.

In January 2007, we entered into an agreement with Iberdrola Cantabria for the monitoring, operation and maintenance of the 40kW PowerBuoy system and the ocean-based substation and infrastructure to be manufactured and deployed under the Spain construction agreement. Under this operations and maintenance agreement, we are required to provide services for two years following provisional acceptance of the PowerBuoy system and substation and infrastructure. We are to be paid a fixed fee for scheduled maintenance, ongoing operations and other routine services. In connection with any unscheduled repairs we perform under the operations and maintenance agreement, Iberdrola Cantabria and we will agree on the fees, if any, and timing, for those services. To the extent we would otherwise have profits from the fixed fee at the end of the two-year initial term of the agreement, we are obligated to reimburse Iberdrola Cantabria for any fees paid to us for unscheduled repairs. If the costs we actually incur in connection with providing services under the operations and maintenance agreement exceed the fees we receive, we will incur a loss in connection with these services, which could adversely affect our financial condition and results of operations.

The scope of our operations to date has been limited, and we do not have experience operating on the scale that we believe will be necessary to achieve profitable operations. Our current personnel, facilities, systems and internal procedures and controls are not adequate to support our future growth. We plan to add sales, marketing and engineering offices in additional locations, including Australia, Japan, continental Europe

To manage the expansion of our operations, we will be required to improve our operational and financial systems, procedures and controls, increase our manufacturing capacity and throughput and expand, train and manage our employee base, which must increase significantly if we are to be able to fulfill our current manufacturing and growth plans. Our management will also be required to maintain and expand our relationships with customers, suppliers and other third parties, as well as attract new customers and suppliers. If we do not meet these challenges, we may be unable to take advantage of market opportunities, execute our business strategies or respond to competitive pressures.

Our agreements with customers will generally include guarantees with respect to the quality and performance of our PowerBuoy systems. For example, our agreement to complete the first phase of the construction of a 1.39MW wave power station off the coast of Santoña, Spain contains guarantees associated with this first phase regarding the quality, replacement and repair of the 40kW PowerBuoy system and ocean-based substation and the level of power output of the 40kW PowerBuoy system.

Because of the limited operating history of our PowerBuoy systems, we have been required to make assumptions regarding the durability, reliability and performance of the systems, and we cannot predict whether and to what extent we may be required to perform under the guarantees that we expect to give our customers. Our assumptions could prove to be materially different from the actual performance of our PowerBuoy systems, causing us to incur substantial expense to repair or replace defective systems in the future. We will bear the risk of claims long after we have sold our PowerBuoy systems and recognized revenue. Moreover, any widespread product failures could adversely affect our business, financial condition and results of operations.

In the nine months ended January 31, 2007, we generated substantially all of our revenues from three entities. The US Navy, our largest customer, accounted for approximately 57% of our revenues during that period, while Iberdrola and Total accounted for 32% of our revenues. In fiscal 2006, revenues from the US Navy accounted for approximately 61% of our total revenues. We expect that revenues from the US Navy will account for a substantial portion of our total revenues in fiscal 2007. In addition, our current contract with the US Navy expires in April 2008. We will be required to enter into additional contracts with the US Navy, which will require appropriation by the US Congress and the US Navy in order to receive additional funding. Additional funding for our project with the US Navy may not be approved or we may not be able to negotiate future agreements with the US Navy on acceptable terms, if at all.

Generally, we recognize revenue on the percentage-of-completion method based on the ratio of costs incurred to total estimated costs at completion. In certain circumstances, revenue under contracts that have specified milestones or other performance criteria may be recognized only when our customer acknowledges that such criteria have been satisfied. In addition, recognition of revenue (and the related costs) may be deferred for fixed-price contracts until contract completion if we are unable to reasonably estimate the total costs of the project prior to completion.

Because we currently have a small number of customers and contracts, problems with a single contract can adversely affect our business, financial condition and results of operations. For example, our revenues in fiscal 2006 decreased significantly from fiscal 2005 primarily as a result of unanticipated delays in our contract with the US Navy.

Historically, we have relied on a small group of customers for substantially all of our revenue, and such concentration will continue for the foreseeable future. The loss of any of our customers or their default in payment could adversely affect our business, financial condition and results of operations.

An important element of our business strategy is to enter into development agreements and strategic alliances with regional utility and energy companies committed to providing electricity from renewable energy sources. If we are unable to reach agreements with suitable alliance partners, we may fail to meet our business objectives for the commercialization of our PowerBuoy system. We may face significant competition in seeking appropriate alliance partners. Moreover, these development agreements and strategic alliances are complex to negotiate and time consuming to document. We may not be successful in our efforts to establish additional strategic relationships or other alternative arrangements. The terms of any additional strategic relationships or other arrangements that we establish may not be favorable to us. In addition, these relationships may not be successful, and we may be unable to sell and market our PowerBuoy systems to these companies and their affiliates and customers in the future, or growth opportunities may not materialize, any of which could adversely affect our business, financial condition and results of operations.

It is part of our strategy to co-invest in wave power projects with third parties through joint ventures by acquiring non-controlling interests in special purpose entities. In these situations, we will not be in a position to exercise sole decision-making authority regarding the joint venture. Investments in joint ventures involve risks that would not be present were a third party not involved, including the possibility that our co-venturers might become bankrupt or fail to fund their share of required capital contributions. Our co-venturers may have economic or other business interests or goals that are inconsistent with our business interests or goals, and may be in a position to take actions that are contrary to our policies or objectives. Disputes between us and our co-venturers may result in litigation or arbitration that would increase our expenses and prevent our officers and/or directors from focusing their time and effort on our business. Consequently, actions by, or disputes with, partners or co-venturers might result in subjecting wave power projects undertaken by the joint venture to additional risk.

The renewable energy industry, particularly in our targeted markets of coastal North America, the west coast of Europe, the coasts of Australia and the east coast of Japan, is highly competitive and continually evolving as participants strive to distinguish themselves and compete with the larger electric power industry. Competition in the renewable energy industry is likely to continue to increase with the advent of several renewable energy technologies, including tidal and ocean current technologies. If we are not successful in manufacturing systems that generate competitively priced electricity, we will not be able to respond effectively to competitive pressures from other renewable energy technologies.

Moreover, the success of renewable energy generation technologies may cause larger electric utility and other energy companies with substantial financial resources to enter into the renewable energy industry. These companies, due to their greater capital resources and substantial technical expertise, may be better positioned to develop new technologies.

Our inability to respond effectively to such competition could adversely affect our business, financial condition and results of operations.

We plan to manufacture key components of our PowerBuoy systems, including the advanced control and generation systems. However, we have only manufactured our PowerBuoy systems in limited quantities for use in development and testing and have little commercial manufacturing experience. Our future success depends on our ability to significantly increase both our manufacturing capacity and production throughput in a cost-effective and efficient manner. In order to meet our growth objectives, by the end of fiscal 2010 we will need to increase our engineering and manufacturing staff by over 120 people. There is intense competition for hiring qualified technical and engineering personnel, and we may not be able to hire a sufficient number of qualified engineers to allow us to meet our growth objectives.

We may be unable to develop efficient, low-cost manufacturing capabilities and processes that will enable us to meet the quality, price, engineering, design and production standards or production volumes necessary to successfully commercialize our PowerBuoy systems. If we cannot do so, we may be unable to expand our business, satisfy our contractual obligations or become profitable. Even if we are successful in developing our manufacturing capabilities and processes, we may not be able to do so in time to meet our commercialization schedule or satisfy the requirements of our customers.

We are highly dependent on third parties to supply or manufacture components of our PowerBuoy systems. If, for any reason, our third-party manufacturers or vendors are not willing or able to provide us with components or supplies in a timely fashion, or at all, our ability to manufacture and sell many of our products could be impaired.

We do not have long-term contracts with our third-party manufacturers or vendors. If we do not develop ongoing relationships with vendors located in different regions, we may not be successful at controlling unit costs as our manufacturing volume increases. We may not be able to negotiate new arrangements with these third parties on acceptable terms, if at all.

In addition, we rely on third parties, under our oversight, for the deployment and mooring of our PowerBuoy systems. We have utilized several different deployment methods, including towing the PowerBuoy system to the deployment location, and transporting the PowerBuoy system to the deployment location by barge or ocean workboat. If these third parties do not properly deploy our systems, cannot effectively deploy the PowerBuoy system on a large, commercial scale or otherwise do not perform adequately, or if we fail to recruit and retain third parties to deploy our systems in particular geographic areas, this could adversely affect our business, financial condition and results of operations.

Our manufacturing operations, in particular some of the activities undertaken by our third-party suppliers and manufacturers, involve the controlled use of hazardous materials. Accordingly, our third-party contractors and we are subject to foreign, federal, state and local laws governing the protection of the environment and human health and safety, including those relating to the use, handling and disposal of these materials. We cannot completely eliminate the risk of accidental contamination or injury from these hazardous materials. In the event of an accident or failure to comply with environmental or health and safety laws and regulations, we could be held liable for resulting damages, including damages to natural resources, fines and penalties, and any such liability could adversely affect our business, financial condition and results of operations.

Environmental laws and regulations are complex, change frequently and have tended to become stringent over time. While we have budgeted for future capital and operating expenditures to maintain compliance, we cannot assure you that environmental laws and regulations will not change or become more stringent in the future. Therefore, we cannot assure you that our costs of complying with current and future environmental and

We derive a significant portion of our revenue from US federal government contracts, which are subject to special funding restrictions, regulatory requirements and eligibility standards and which the government may terminate at any time or determine not to extend after their scheduled expiration. During fiscal 2006, we derived approximately 61% of our total revenue from contracts with the US Navy.

US federal government contracts are subject to funding restrictions that generally limit the government’s funding commitments to one federal fiscal year. There is no guarantee that our federal contracts will continue to be funded even if we perform successfully. If sufficient funds are not made available for subsequent contract periods of a multi-year program, the government’s obligations will end, which in turn will adversely affect our business, financial condition and results of operations.

Our contracts with the US Navy contain provisions permitting it to terminate the contract for its convenience, as well as for our default. A decision by a government agency not to exercise option periods or to terminate contracts could result in significant revenue shortfalls.

If the government terminates a contract for convenience, then we may recover only our incurred or committed costs, settlement expenses and profit on work completed prior to the termination. We cannot recover anticipated profit on terminated work. If the government terminates a contract for default, then we may not recover even those amounts, and instead we may be liable for excess costs incurred by the government in procuring undelivered items and services from another source. We cannot predict if the government will terminate or choose not to extend our Federal government contracts. The government has never terminated any of our contracts; however, it may do so at any time.

US federal government contracts are also subject to contractual and regulatory requirements that may increase our costs of doing business and could expose us to substantial contractual damages, civil fines and criminal penalties for noncompliance. These requirements include business ethics, equal employment opportunity, environmental, foreign purchasing, most-favored pricing and accounting provisions, among others. Payments that we receive under US federal government contracts are subject to audit and potential refunds for at least three years after the final contract payment is received.

Most of our federal contracts were awarded through a special US government program designed to promote innovative research by small businesses called Small Business Innovation Research, or SBIR. The SBIR program provides funds to qualified small businesses to further their technological research and development activities and provides incentives to these companies to profit from commercialization of their technology. SBIR funding represents both revenues and outside research and development investment dollars for companies that receive it. The program is open to companies that are majority owned and controlled by individual US citizens or permanent resident aliens, or by a parent entity that meets this standard. Our revenues from the SBIR program were approximately $0.8 million for the first nine months of fiscal 2007 and approximately $1.1 million for fiscal 2006.

Increased institutional, corporate or foreign ownership as a result of this offering will likely make us ineligible for the SBIR program, which may adversely affect our ability to win future government contracts. We intend to continue to seek research and development funding from other sources, including funding from existing government customers under non-SBIR programs. Our inability to replace SBIR contracts with funds from other sources could result in reduced revenues and higher internal research and development costs, and therefore adversely affect our operating results.

We market and sell, and plan to market and sell, our products in a number of foreign countries, including France, Spain, the United Kingdom, Australia and Japan, and we are therefore subject to risks associated with having international operations. International operations accounted for 4% of our revenues in fiscal 2005, 9% of our revenues in fiscal 2006 and 35% of our revenues for the first nine months of fiscal 2007. Risks inherent in international operations include, but are not limited to, the following:

Our business in foreign markets requires us to respond to rapid changes in market conditions in these countries. Our overall success as a global business depends, in part, on our ability to succeed in differing legal, regulatory, economic, social and political conditions. We may not be able to develop and implement policies and strategies that will be effective in each location where we do business, which in turn could adversely affect our business, financial condition and results of operations.

We have in the past needed to raise funds to operate our business, and we may need to raise additional funds to manufacture our PowerBuoy systems in commercial quantities. If we are unable to raise additional funds when needed, our ability to operate and grow our business could be impaired. We do not know whether we will be able to secure additional funding or funding on terms favorable to us. Our ability to obtain additional funding will be subject to a number of factors, including market conditions, our operating performance and investor sentiment. These factors may make the timing, amount, terms and conditions of additional funding unattractive. If we issue additional equity securities, our existing stockholders may experience dilution or be subordinated to any rights, preferences or privileges granted to the new equity holders.

Our financial results may fluctuate as a result of a number of factors, many of which are outside of our control. For these reasons, comparing our financial results on a period-to-period basis may not be meaningful, and you should not rely on our past results as an indication of our future performance. Our future quarterly and annual expenses as a percentage of our revenues may be significantly different from those we have recorded in the past or which we expect for the future. Our financial results in some quarters may fall below expectations. Any of these events could cause our stock price to fall. Each of the risk factors listed in this “Risk Factors” section, including the following factors, may adversely affect our business, financial condition and results of operations:

Our reporting currency is the US dollar, and we conduct our business and incur costs in the local currency of most countries in which we operate. As a result, we are subject to currency translation risk. In fiscal 2006, approximately 9% of our revenues were generated outside the United States and denominated in Euros and in the first nine months of fiscal 2007, 32% of our revenues were generated outside the United States and denominated in Euros and 3% of our revenues were generated outside the United States and denominated in Australian dollars. We expect a large percentage of our revenues to be generated outside the United States and denominated in foreign currencies in the future. Changes in exchange rates between foreign currencies and the US dollar could affect our revenues and cost of revenues, and could result in exchange losses. In addition, we incur currency transaction risk whenever one of our operating subsidiaries enters into either a purchase or a sales transaction using a different currency from our reporting currency. For example, our agreement with Iberdrola Cantabria for the first phase of the construction of a wave power station off the coast of Santoña, Spain is denominated in Euros, and we expect that we will enter into a number of purchase and supply contracts with local Spanish companies also denominated in Euros in connection with the project. We cannot accurately predict the impact of future exchange rate fluctuations on our results of operations. Currently, we do not engage in any exchange rate hedging activities and, as a result, any volatility in currency exchange rates may have an immediate adverse effect on our business, results of operations and financial condition.

The market for electricity generation equipment is heavily influenced by foreign, federal, state and local government regulations and policies concerning the electric utility industry, as well as policies promulgated by electric utilities. These regulations and policies often relate to electricity pricing and connection to the power grid. In the United States and in a number of other countries, these regulations and policies currently are being modified and may be modified again in the future. Utility company and independent power producer purchases of, or further investment in the research and development of, alternative energy sources, including wave energy technology, could be deterred by these regulations and policies, which could result in a significant reduction in the potential demand for our PowerBuoy systems.

As the renewable energy industry continues to develop and as the generation of power from wave energy in particular achieves commercial acceptance, we anticipate that wave energy technology and our PowerBuoy systems and their deployment will be subject to increased oversight and regulation. We are unable to predict the nature or extent of regulations that may be imposed or adopted. Any new government regulations or utility policies pertaining to wave energy or our PowerBuoy systems may result in significant additional expenses to us and our customers and, as a result, could adversely affect our business, financial condition and results of operations.

Offshore development of electric power generating facilities is heavily regulated. Each of our planned projects is subject to multiple permitting and approval requirements. With respect to our projects in Spain and France, we are dependent upon our customers to obtain any necessary permits and approvals, and with respect to our project in Cornwall, England, we are dependent on a regional government agency for such permits and approvals. Due to the unique nature of large scale commercial wave power stations, we would expect our projects to receive close scrutiny by permitting agencies, approval authorities and the public, which could result in substantial delay in the permitting process. Successful challenges by any parties opposed to our planned projects could result in conditions limiting the project size or in the denial of necessary permits and approvals.

If we are unable to obtain necessary permits and approvals in connection with any or all of our projects, those projects would not be implemented and our business, financial condition and results of operations would be adversely affected. Further, we cannot assure you that we have been or will be at all times in complete compliance with all such permits and approvals. If we violate or fail to comply with these permits and approvals, we could be fined or otherwise sanctioned by regulators.

Our PowerBuoy systems are deployed in the ocean where they are subject to many hazards including severe storms and hurricanes, which could damage them and result in service interruptions. Our systems are also subject to more frequent lock-downs caused by higher waves during winter storm and hurricane seasons, which will reduce annual energy output. We cannot predict whether we will be able to recover from our insurance providers the additional costs that we may incur due to damage caused to our PowerBuoy systems, or whether we will continue to be able to obtain insurance for hurricane- and storm-related damages or, if obtainable and carried, whether this insurance will be adequate to cover our liabilities. Any future hurricane-or storm-related costs could adversely affect our business, financial condition and results of operations.

Our systems are designed to work in sites with average annual wave energy of at least 20kW per meter of wave front. Not all coastal areas worldwide have appropriate natural resources for our PowerBuoy systems to harness wave energy. Seasonal and local variations, water depth and the effect of particular locations of islands and other geographical features may limit our ability to deploy our PowerBuoy systems in coastal areas. If we are unable to identify and deploy PowerBuoy systems at sufficient sites near major population centers, our ability to grow our business could be adversely affected.

Our success depends on the skills, experience and efforts of our senior management and other key development, manufacturing, and sales and marketing employees. We cannot be certain that we will be able to attract, retain and motivate such employees. The loss of the services of one or more of these employees could have a material adverse effect on our business. There is a risk that we will not be able to retain or replace these key employees. We have entered into employment agreements with Dr. George Taylor, our chief executive officer, Charles Dunleavy, our senior vice president and chief financial officer, Mark Draper, the chief executive officer of our UK subsidiary, and John Baylouny, our senior vice president, engineering; however, the agreements permit the employees to terminate their employment with little notice. Implementation of our expansion plans will be highly dependent upon our ability to hire and retain additional senior executives.

In addition, our anticipated growth will require us to hire a significant number of qualified technical, commercial and administrative personnel. In order to meet our short-term goals, by the end of 2007, we plan to add approximately 15 to 20 employees, including a vice president of business development. The remainder will primarily be engineers with varying areas of expertise. By the end of fiscal 2010, we will need to increase

From time to time, we evaluate potential strategic acquisitions of complementary businesses, products or technologies, as well as consider joint ventures and other collaborative projects. We may not be able to identify appropriate acquisition candidates or strategic partners, or successfully negotiate, finance or integrate any businesses, products or technologies that we acquire. We do not have any experience with acquiring companies or products. Any acquisition we pursue could diminish the proceeds from this offering available to us for other uses or be dilutive to our stockholders, and could divert management’s time and resources from our core operations.

Strategic acquisitions, investments and alliances with third parties could subject us to a number of risks, including risks associated with sharing proprietary information and loss of control of operations that are material to our business. In addition, strategic acquisitions, investments and alliances may be expensive to implement. For example, under the France project, our entitlement to retain our current percentage interest is subject to our ability to make a proportionate capital investment, which we may be unable to finance. Moreover, strategic acquisitions, investments and alliances subject us to the risk of non-performance by a counterparty, which may in turn lead to monetary losses that materially and adversely affect our business, financial condition and results of operations.

Section 404 of the Sarbanes-Oxley Act of 2002 will require us to document and test the effectiveness of our internal control over financial reporting in accordance with an established internal control framework and to report on our conclusion as to the effectiveness of our internal controls. It will also require an independent registered public accounting firm to test our internal control over financial reporting and report on the effectiveness of such controls for our fiscal year ending April 30, 2008 and subsequent years. An independent registered public accounting firm will also be required to test, evaluate and report on the completeness of our assessment. In addition, upon completion of this offering, we will be required under the Securities Exchange Act of 1934 to maintain disclosure controls and procedures and internal control over financial reporting. Moreover, it may cost us more than we expect to comply with these control- and procedure-related requirements.

We may in the future discover areas of our internal controls that need improvement, particularly with respect to businesses that we may acquire. We cannot be certain that any remedial measures we take will ensure that we implement and maintain adequate internal controls over our financial processes and reporting in the future. Any failure to implement required new or improved controls, or difficulties encountered in their implementation, could harm our operating results or cause us to fail to meet our reporting obligations. If we are unable to conclude that we have effective internal control over financial reporting, or if our independent registered public accounting firm is unable to provide us with an unqualified opinion regarding the effectiveness of our internal control over financial reporting as of April 30, 2008 and in future periods as required by Section 404, investors could lose confidence in the reliability of our consolidated financial statements, which could result in a decrease in the value of our common stock. Failure to comply with

Our success and ability to compete depends in part upon our ability to obtain protection in the United States and other countries for our products by establishing and maintaining intellectual property rights relating to or incorporated into our technology and products. We own a variety of patents and patent applications in the United States and corresponding patents and patent applications in several foreign jurisdictions. However, we have not obtained patent protection in each market in which we plan to compete. In addition, we do not know how successful we would be should we choose to assert our patents against suspected infringers. Our pending and future patent applications may not issue as patents or, if issued, may not issue in a form that will be advantageous to us. Even if issued, patents may be challenged, narrowed, invalidated or circumvented, which could limit our ability to stop competitors from marketing similar products or limit the length of term of patent protection we may have for our products. Changes in either patent laws or in interpretations of patent laws in the United States and other countries may diminish the value of our intellectual property or narrow the scope of our patent protection, which could in turn adversely affect our business, financial condition and results of operations.

Our agreements with the US Navy help fund research and development of our PowerBuoy system. When new technologies are developed with US federal government funding, the government obtains certain rights in any resulting patents, technical data and software, generally including, at a minimum, a nonexclusive license authorizing the government to use the invention, technical data or software for non-commercial purposes. These rights may permit the government to disclose our confidential information to third parties and to exercise “march-in” rights. March-in rights refer to the right of the US government to require us to grant a license to the technology to a responsible applicant or, if we refuse, the government may grant the license itself. US government-funded inventions must be reported to the government. US government funding must be disclosed in any resulting patent applications, and our rights in such inventions will normally be subject to government license rights, periodic post-contract utilization reporting, foreign manufacturing restrictions and march-in rights.

The government can exercise its march-in rights if it determines that action is necessary because we fail to achieve practical application of the technology or because action is necessary to alleviate health or safety needs, to meet requirements of federal regulations or to give preference to US industry. Our government-sponsored research contracts are subject to audit and require that we provide regular written technical updates on a monthly, quarterly or annual basis, and, at the conclusion of the research contract, a final report on the results of our technical research. Because these reports are generally available to the public, third parties may obtain some aspects of our sensitive confidential information. Moreover, if we fail to provide these reports or to provide accurate or complete reports, the government may obtain rights to any intellectual property arising from the related research. Funding from government contracts also may limit when and how we can deploy our technology developed under those contracts.

In addition to patented technology, we rely upon unpatented proprietary technology, processes and know-how, particularly with respect to our PowerBuoy control and electricity generating systems. We generally seek to protect this information in part by confidentiality agreements with our employees, consultants and third

Our products may infringe or be claimed to infringe patents or patent applications under which we do not hold licenses or other rights. Third parties may own or control these patents and patent applications in the United States and abroad. From time to time, we receive correspondence from third parties offering to license patents to us. Correspondence of this nature might be used to establish that we received notice of certain patents in the event of subsequent patent infringement litigation. Third parties could bring claims against us that would cause us to incur substantial expenses and, if successfully asserted against us, could cause us to pay substantial damages. Further, if a patent infringement suit were brought against us, we could be forced to stop or delay manufacturing or sales of the product or component that is the subject of the suit.

As a result of patent infringement claims, or in order to avoid potential claims, we may choose or be required to seek a license from the third party and be required to pay license fees or royalties or both. These licenses may not be available on acceptable terms, or at all. Even if we were able to obtain a license, the rights may be nonexclusive, which could result in our competitors gaining access to the same intellectual property. Ultimately, we could be forced to cease some aspect of our business operations if, as a result of actual or threatened patent infringement claims, we are unable to enter into licenses on acceptable terms. This could significantly and adversely affect our business, financial condition and results of operations.

In addition to infringement claims against us, we may become a party to other types of patent litigation and other proceedings, including interference proceedings declared by the United States Patent and Trademark Office and opposition proceedings in the European Patent Office, regarding intellectual property rights with respect to our products and technology. The cost to us of any patent litigation or other proceeding, even if resolved in our favor, could be substantial. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace. Patent litigation and other proceedings may also absorb significant management time.

After we reincorporate in Delaware, provisions of our certificate of incorporation and bylaws may discourage, delay or prevent a merger, acquisition or other change in control that stockholders may consider favorable, including transactions in which our stockholders might otherwise receive a premium for their shares. These provisions may also prevent or frustrate attempts by our stockholders to replace or remove our management. These provisions include:

The affirmative vote of the holders of at least 75% of our shares of capital stock entitled to vote is necessary to amend or repeal the above provisions of our certificate of incorporation. In addition, absent approval of our board of directors, our bylaws may only be amended or repealed by the affirmative vote of the holders of at least 75% of our shares of capital stock entitled to vote.

In addition, Section 203 of the Delaware General Corporation Law prohibits a publicly held Delaware corporation from engaging in a business combination with an interested stockholder, generally a person which

Prior to this offering, there has been no public market for shares of our common stock in the United States. Our common stock has been listed on the AIM market of the London Stock Exchange plc, referred to as the AIM market, under the symbol “OPT” since October 2003. However, there is currently a limited volume of trading in our common stock on the AIM market, which limits the liquidity of our common stock on that market. We cannot predict when or whether investor interest in our common stock on the AIM market might lead to an increase in its market price or the development of a more active trading market or how liquid that market might become.

The initial public offering price for our common stock was determined through negotiations with the underwriters based on a number of factors, including the historic trading prices of our common stock on the AIM market, that might not be indicative of prices that will prevail in the trading market for our common stock in the United States. An active trading market for our shares in the United States may never develop or be sustained following this offering. If an active market for our common stock does not develop, it may be difficult to sell shares you purchase in this offering without depressing the market price for the shares, or at all.

Following this offering and after our common stock is traded on The Nasdaq Global Market, we currently expect to continue to list our common stock on the AIM market. We cannot predict the effect of having our common stock traded or listed on both of these markets. However, the dual listing of our common stock may dilute the liquidity of our common stock in one or both markets and may adversely affect the development of an active trading market for our shares in the United States.

The price of our common stock has been volatile on the AIM market, and after this offering our stock price is likely to continue to be volatile. The stock market in general has experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility, investors may not be able to sell their common stock at or above the initial public offering price. The market price for our common stock may be influenced by many factors, including:

All of the shares being sold in this offering will be freely tradable without restriction or further registration under the federal securities laws, unless purchased by our “affiliates” as that term is defined in Rule 144 under the Securities Act. The approximately 2.4 million shares held by our directors and executive officers and the selling stockholders will be eligible for sale upon completion of this offering pursuant to Rule 144 subject to the volume limitations and other applicable conditions of Rule 144 upon the expiration of 180-day lock-up agreements described under “Underwriting”. The balance of our outstanding shares will be immediately eligible for sale after the completion of this offering pursuant to Rule 144(k) without regard to volume limitations and other applicable conditions of Rule 144 or pursuant to other exemptions, including the 2,000,000 shares of our common stock that were sold in an offering on the AIM market in 2003.

We also intend to register all shares of our common stock that we may issue under our employee benefit plans. Once we register these shares, they can be freely sold in the public market upon issuance, subject to the lock-up agreements described in “Underwriting.” Sales of a substantial number of shares of our common stock, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock.

Our management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our operating results or enhance the value of our common stock. Our stockholders may not agree with the manner in which our management chooses to allocate and spend the net proceeds. The failure by our management to apply these funds effectively could result in financial losses that could have a material adverse effect on our business and cause the price of our common stock to decline. Pending their use, we may invest our net proceeds from this offering in a manner that does not produce income or that loses value.

We have not paid any cash dividends on our common stock to date. We currently intend to retain our future earnings, if any, to fund the development and growth of our business. In addition, the terms of any future debt agreements may preclude us from paying dividends. As a result, capital appreciation, if any, of our common stock will be your sole source of gain for the foreseeable future.

The initial public offering price of our common stock is substantially higher than the net tangible book value per share of our common stock. Therefore, if you purchase shares of our common stock in this offering, your interest will be diluted immediately to the extent of the difference between the initial public offering price per share of our common stock and the net tangible book value per share of our common stock after this offering. See “Dilution.”

In accordance with the rules of the AIM market, we are required to disclose information regarding beneficial owners of three percent or more of our outstanding common stock to the AIM market. In order to allow us to comply with the AIM rules, our bylaws that will be in effect upon completion of the offering contain a provision requiring any beneficial owner of three percent or more of our outstanding common stock to notify us of his or her shareholdings, as well as of any change in his or her beneficial ownership of one percent or more of our outstanding common stock. Comparatively, none of US state or US federal laws that will be applicable to us after the offering or the rules of the SEC or The Nasdaq Global Market require stockholders to report this beneficial ownership information to us or us to disclose this information to the

As a public company in the United States, we will incur significant legal, accounting and other expenses that we have not incurred to date. In addition, the Sarbanes-Oxley Act of 2002, as well as new rules subsequently implemented by the SEC and The Nasdaq Stock Market, have required changes in corporate governance practices of public companies in the United States. We expect these new rules and regulations to increase our legal and financial compliance costs and to make some activities more time-consuming and costly. In addition, we will incur additional costs associated with our United States public company reporting requirements. We also expect these new rules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain qualified persons to serve on our board of directors or as executive officers. We are currently evaluating and monitoring developments with respect to these new rules, and we cannot predict or estimate the amount of additional costs we may incur or the timing of such costs.

This prospectus, including the sections titled “Prospectus Summary,” “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Business,” contains forward-looking statements. Forward-looking statements convey our current expectations or forecasts of future events. All statements contained in this prospectus other than statements of historical fact are forward-looking statements. Forward-looking statements include statements regarding our future financial position, business strategy, budgets, projected costs, plans and objectives of management for future operations. The words “may,” “continue,” “estimate,” “intend,” “plan,” “will,” “believe,” “project,” “expect,” “anticipate” and similar expressions may identify forward-looking statements, but the absence of these words does not necessarily mean that a statement is not forward-looking. These forward-looking statements include, among other things, statements about:

Any or all of our forward-looking statements in this prospectus may turn out to be inaccurate. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our financial condition, results of operations, business strategy and financial needs. They may be affected by inaccurate assumptions we might make or unknown risks and uncertainties, including the risk, uncertainties and assumptions described in “Risk Factors.” In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus may not occur as contemplated, and actual results could differ materially from those anticipated or implied by the forward-looking statements.

You should not unduly rely on these forward-looking statements, which speak only as of the date of this prospectus. Unless required by law, we undertake no obligation to publicly update or revise any forward-looking statements to reflect new information or future events or otherwise. You should, however, review the factors and risks we describe in the reports we will file from time to time with the SEC after the date of this prospectus. See “Where You Can Find More Information.”

We estimate that the net proceeds to us from the sale of the 5,000,000 shares of common stock we are offering will be approximately $94.8 million, assuming an initial public offering price of $21.00 per share, the midpoint of the estimated price range shown on the cover of this prospectus, and after deducting underwriting discounts and commissions and the estimated offering expenses payable by us. If the underwriters exercise their over-allotment option in full, we estimate the net proceeds to us from this offering will be approximately $107.6 million. We will not receive any proceeds from the sale of shares of common stock by the selling stockholders as a result of any exercise by the underwriters of their over-allotment option.

The principal purposes of this offering are to obtain additional capital resources to construct demonstration wave power stations and to fund minority investments in wave station projects to encourage market adoption of our wave power stations; to fund the continued development and commercialization of our PowerBuoy system, including increases in system output; to expand our international sales and marketing capabilities; and for working capital and general corporate purposes, including potential acquisitions of complementary businesses, products or technologies. We intend to use the net proceeds of this offering as follows:

We may also use a portion of the net proceeds to acquire complementary products, technologies or businesses, although we currently have no agreements or commitments with respect to any such transactions.

Assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, after deducting the estimated underwriting discounts and commissions and other estimated offering expenses payable by us in connection with the offering, a $1.00 increase (decrease) in the assumed public offering price of $21.00 per share of common stock would increase (decrease) our expected net proceeds by approximately $4.7 million.

As of the date of this prospectus, we cannot specify with certainty all of the particular uses for the net proceeds of this offering. The amounts and timing of our actual expenditures may vary significantly from our expectations depending upon numerous factors, including our development and commercialization efforts, our operating costs and capital expenditures, our future revenues and cash generated by operations. Accordingly, we will retain broad discretion to allocate the net proceeds of this offering among the identified uses described above, and we reserve the right to change the allocation of the net proceeds of this offering.

Pending use of the proceeds from this offering, we intend to invest the proceeds in short-term, investment-grade, interest-bearing instruments.

Prior to this offering, there has been no trading market for our common stock in the United States. Our common stock has been listed on the AIM market of the London Stock Exchange since October 2003 under the symbol “OPT.” The historical trading prices of our common stock on the AIM market may not be indicative of prices that will prevail in the trading market for our common stock in the United States.

The following table sets forth, for the periods indicated, the high and low closing sale prices for our common stock on the AIM market as reported by the London Stock Exchange. The sales prices have been adjusted to give effect to a one-for-ten reverse stock split of our common stock to be effective prior to this offering. The sales prices for our shares of common stock on the AIM market are quoted in pound sterling (£), the lawful currency of the United Kingdom. The following table also shows the high and low closing sales price of our common stock (as adjusted to give effect to a one-for-ten reverse split to be effective prior to this offering) expressed in dollars based upon the average noon buying rate for pound sterling for the periods indicated.

The following table sets forth, for the periods indicated, the high, low, average and period end noon buying rate for pound sterling, expressed in dollars per pound sterling in New York City as certified for customs purposes by the Federal Reserve Bank of New York.

The initial public offering price for the common stock being offered by this prospectus was determined by negotiation between us and the underwriters based on a number of factors which are described in “Underwriting — Determination of Offering Price.”

We have never declared or paid any cash dividends on our common stock, and we do not currently anticipate declaring or paying cash dividends on our common stock in the foreseeable future. We currently intend to retain all of our future earnings, if any, to finance the growth and development of our business. Any future determination relating to our dividend policy will be made at the discretion of our board of directors and will depend on a number of factors, including future earnings, capital requirements, financial conditions, future prospects, contractual restrictions and covenants and other factors that our board of directors may deem relevant.

The following table sets forth our cash, cash equivalents and short-term investments and capitalization as of January 31, 2007:

The table above should be read in conjunction with our consolidated financial statements and related notes appearing at the end of this prospectus and the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” section of this prospectus.

This table is based on 5,177,219 shares of our common stock outstanding as of January 31, 2007 (as adjusted to give effect to a one-for-ten reverse split to be effective prior to this offering) and excludes:

If you invest in our common stock, your interest will be diluted immediately to the extent of the difference between the initial public offering price per share you will pay in this offering and the net tangible book value per share of our common stock after this offering.

Our actual net tangible book value as of January 31, 2007 was $26.1 million, or $5.03 per share of common stock. Net tangible book value per share represents the amount of our total tangible assets less total liabilities, divided by the number of shares of common stock outstanding.

After giving effect to the issuance and sale by us of the 5,000,000 shares of common stock in this offering, at an assumed initial public offering price of $21.00 per share, the midpoint of the estimated price range set forth on the cover page of this prospectus, less the underwriting discounts and commissions and estimated offering expenses payable by us, our net tangible book value as of January 31, 2007 would have been $120.8 million, or $11.87 per share of common stock. This represents an immediate increase in net tangible book value per share of $6.84 to existing stockholders and immediate dilution of $9.13 per share to new investors purchasing shares in this offering. Dilution per share to new investors is determined by subtracting the net tangible book value per share after this offering from the initial public offering price per share paid by a new investor. The following table illustrates the per share dilution without giving effect to the over-allotment option granted to the underwriters:

A $1.00 increase (decrease) in the assumed public offering price of $21.00 per share would increase (decrease) the adjusted net tangible book value per share by $0.46, and the dilution per share to new investors by $0.54, assuming the number of shares offered by us in this offering as set forth on the cover page of this prospectus remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

If the underwriters exercise their over-allotment option in full, our net tangible book value will increase to $12.34 per share, representing an immediate increase to existing stockholders of $7.31 per share and an immediate dilution of $8.66 per share to new investors. If any shares are issued in connection with outstanding options, you will experience further dilution.

The following table summarizes as of January 31, 2007 the number of shares of common stock purchased or to be purchased from us, the total consideration paid or to be paid and the average price per share paid by (1) the stockholders that purchased our shares in our October 2003 offering on the AIM market of the London Stock Exchange, (2) other existing stockholders and (3) new investors in this offering, before deducting underwriting discounts and commissions and other estimated expenses of this offering.

The table above is based on shares outstanding as of January 31, 2007 and excludes:

If the underwriters exercise their over-allotment option in full, the following will occur:

You should read the following selected consolidated financial data in conjunction with our consolidated financial statements and the related notes appearing at the end of this prospectus and the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” section of this prospectus. We have derived the consolidated statement of operations data for the fiscal years ended April 30, 2004, 2005 and 2006 and the consolidated balance sheet data as of April 30, 2005 and 2006 from our audited consolidated financial statements, which are included in this prospectus, as audited by KPMG LLP, our independent registered public accounting firm for fiscal 2005 and 2006 and by Deloitte & Touche LLP for fiscal 2004. We have derived the consolidated statement of operations data for the fiscal years ended April 30, 2002 and 2003 and the consolidated balance sheet data as of April 30, 2002, 2003 and 2004 from our audited consolidated financial statements, which are not included in this prospectus. We have derived the consolidated statement of operations data for the nine months ended January 31, 2006 and 2007 and the consolidated balance sheet data as of January 31, 2007 from our unaudited consolidated financial statements, which are included in this prospectus. The unaudited summary consolidated financial statement data include, in our opinion, all adjustments, consisting only of normal recurring adjustments, that are necessary for a fair presentation of our financial position and results of operations for these periods. Our historical results for any prior period are not necessarily indicative of results to be expected for any future period.

You should read the following discussion and analysis of our financial condition and results of operations together with our consolidated financial statements and the related notes and other financial information included elsewhere in this prospectus. Some of the information contained in this discussion and analysis or set forth elsewhere in this prospectus, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. You should review the “Risk Factors” section of this prospectus for a discussion of important factors that could cause actual results to differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

We develop and are commercializing proprietary systems that generate electricity by harnessing the renewable energy of ocean waves. Our PowerBuoy systems use proprietary technologies to convert the mechanical energy created by the rising and falling of ocean waves into electricity. We currently offer two PowerBuoy products, our utility PowerBuoy system and our autonomous PowerBuoy system.

We market our utility PowerBuoy system, which is designed to supply electricity to a local or regional power grid, to utilities and other electrical power producers seeking to add electricity generated by wave energy to their existing electricity supply. We market our autonomous PowerBuoy system, which is designed to generate power for use independently of the power grid, to customers that require electricity in remote locations. We believe there are a variety of potential applications for our autonomous PowerBuoy system, including sonar and radar surveillance, offshore cellular phone service, tsunami warning, oceanographic data collection, offshore platforms and offshore aquaculture. We also offer our customers operations and maintenance services for our PowerBuoy systems, which are expected to provide a source of recurring revenues.

We were incorporated in New Jersey in April 1984 and began commercial operations in 1994. We currently have five wholly owned subsidiaries, Ocean Power Technologies Ltd., Reedsport OPT Wave Park LLC, Oregon Wave Energy Partners I, LLC, Oregon Wave Energy Partners II, LLC and Fairhaven OPT Ocean Power LLC, and we own approximately 88% of the ordinary shares of Ocean Power Technologies (Australasia) Pty Ltd. Our revenues have been generated from research contracts and development and construction contracts relating to our wave energy technology. The development of our technology has been funded by capital we raised and by development engineering contracts we received starting in fiscal 1995. In fiscal 1996, we received the first of several research contracts with the US Navy to study the feasibility of wave energy. As a result of those research contracts, we entered into our first development and construction contract with the US Navy in fiscal 2002 under a still on-going project for the development and construction of a grid-connected wave power station at the US Marine Corps Base in Oahu, Hawaii. We generated our first revenue relating to our autonomous PowerBuoy system from contracts with Lockheed Martin Corporation in fiscal 2003, and we entered into our first development and construction contract with Lockheed Martin in fiscal 2004 for the development and construction of a prototype demonstration autonomous PowerBuoy system. In fiscal 2005, we entered into a development agreement with an affiliate of Iberdrola S.A., a large electric utility company located in Spain and one of the largest renewable energy producers in the world, and other parties to jointly study the possibility of developing a wave power station off the coast of northern Spain. An affiliate of Total S.A., which is one of the world’s largest oil and gas companies, joined the development agreement in June 2005. In January 2006, we completed the assessment phase of the project, and in July 2006 we entered into an agreement with Iberdrola Energias Marinas de Cantabria, S.A. to complete the first phase of the construction of a 1.39 megawatt, or MW, wave power station. In addition, we have entered into a contract with affiliates of Iberdrola and Total to assess the viability of a 2 to 5MW power station off the coast of France.

Our fiscal year ends on April 30. For the nine months ended January 31, 2007, we generated revenues of $1.5 million and incurred a net loss of $5.5 million, and for fiscal 2006 we generated revenues of $1.7 million and incurred a net loss of $7.1 million. As of January 31, 2007, our accumulated deficit was $34.1 million. We have not been profitable since inception, and we do not know whether or when we will become profitable

The following describes certain line items in our statement of operations and some of the factors that affect our operating results.

We have historically generated revenues primarily from the development and construction of our PowerBuoy systems for demonstration purposes and, to a lesser extent, from customer-sponsored research and development. In fiscal 2006, we derived approximately 96% of our revenues from government and commercial development and construction contracts and 4% of our revenues from customer-sponsored research and development contracts. For the nine months ended January 31, 2007, we derived approximately 92% of our revenues from government and commercial development and construction contracts and 8% of our revenues from customer-sponsored research and development. Generally, we recognize revenue on the percentage-of-completion method based on the ratio of costs incurred to total estimated costs at completion. In certain circumstances, revenue under contracts that have specified milestones or other performance criteria may be recognized only when our customer acknowledges that such criteria have been satisfied. In addition, recognition of revenue (and the related costs) may be deferred for fixed-price contracts until contract completion if we are unable to reasonably estimate the total costs of the project prior to completion. Because we have a small number of contracts, revisions to the percentage of completion determination or delays in meeting performance criteria or in completing projects may have a significant effect on our revenue for the periods involved. Under our agreement for the first phase of construction of a wave power station off the coast of Santoña, Spain, our revenues are limited to reimbursement for our construction costs without any mark-up and we are required to bear the first €0.5 million of any cost overruns.

Our revenues increased in each of fiscal 2003, 2004 and 2005, but decreased significantly in fiscal 2006 as a result of delays in the timing of contract award and in the approval of the scope of work relating to our project for the US Navy for the development and construction of a wave power station in Hawaii, and the determination by Lockheed Martin and some of its subcontractors not to proceed with a project under consideration that would have utilized our autonomous PowerBuoy system.

The US Navy has been our largest customer since fiscal 2002. The US Navy accounted for approximately 57% of our revenues in the nine months ended January 31, 2007, approximately 61% of our revenues in fiscal 2006, 57% of our revenues in fiscal 2005 and approximately 95% of our revenues in fiscal 2004. We anticipate that the US Navy will continue to account for a substantial portion of our revenue in fiscal 2007 and, if our commercialization efforts are successful, its relative contribution to our revenue will decline thereafter. Lockheed Martin was also a significant customer in fiscal 2006 and 2005, accounting for approximately 22% of our revenues in fiscal 2006 and approximately 32% of our revenues in fiscal 2005.

We currently focus our sales and marketing efforts on coastal North America, the west coast of Europe, the coasts of Australia and the east coast of Japan. In fiscal 2006, we derived 9%, and for the nine months ended January 31, 2007, we derived 35%, of our revenues from outside the United States. The following table provides information regarding the breakdown of our revenues by geographical region for fiscal years 2004, 2005 and 2006 and for the nine months ended January 31, 2007:

Our cost of revenues consists primarily of material, labor and manufacturing overhead expenses, such as engineering expense, equipment depreciation and maintenance and facility related expenses, and includes the cost of PowerBuoy parts and services supplied by third-party suppliers. Cost of revenues also includes PowerBuoy system delivery and deployment expenses.

In the nine months ended January 31, 2007, we operated at a gross loss of approximately $0.6 million, while in fiscal 2006 we operated at a gross loss of $0.3 million and in fiscal 2005 we operated at a gross profit of $0.2 million. Our ability to operate at a gross profit will depend on our success at increasing sales of our PowerBuoy systems and on our ability to manage costs incurred on fixed price commercial contracts.

Our product development costs consist of salaries and other personnel-related costs and the costs of products, materials and outside services used in our product development and research activities. Our product development costs primarily relate to our efforts to increase the output of our current 40 kilowatt, or kW, utility PowerBuoy system to 150kW in 2007, then to 250kW in 2008 and ultimately to 500kW in 2010 and, to a lesser extent, to our research and development of new products, product applications and complementary technologies. We expense all of our product development costs as incurred, except for external patent costs, which we amortize over a 17-year period commencing with the issuance date of each patent.

Our product development costs increased significantly in each of fiscal 2005 and 2006 as a result of the development of our current 40kW utility PowerBuoy system, which was introduced in fiscal 2006. We expect our product development costs to increase in absolute dollars as we continue to increase the output and efficiency of our PowerBuoy systems.

During fiscal 2006, we refocused many of our engineering and development resources that had previously been deployed on our commercial research or product development contracts on the development effort for our current 40kW PowerBuoy system, including the development of the buoy structure, the power take off system and the power grid connection. We introduced our current 40kW PowerBuoy system in fiscal 2006 — one system has been deployed for twelve months off the coast of New Jersey, one system is expected to be deployed in Hawaii for the US Navy project in April 2007 and another system is expected to be deployed for the wave power station off the coast of Spain by October 2007.

Our selling, general and administrative costs consist primarily of salaries and other personnel-related costs for employees engaged in sales and marketing and support of our PowerBuoy systems, promotional and public relations expenses and management and administration expenses in support of sales and marketing, as well as costs for executive, accounting and administrative personnel, professional fees and other general corporate expenses.

We expect our selling, general and administrative costs to increase in absolute dollars as we expand our sales and marketing capabilities, including increased headcount, and as a result of our becoming a public company in the United States.

Interest income, net consists primarily of interest received on cash and cash equivalents and investments in commercial bank-issued certificates of deposit. Most of our cash, cash equivalents and bank-issued certificates of deposit result from the remaining proceeds of our October 2003 offering on the AIM market. Total cash, cash equivalents and certificates of deposit were $26.7 million as of January 31, 2007, $32.4 million as of April 30, 2006 and $38.8 million as of April 30, 2005. We expect that interest income will generally increase during periods of increasing interest rates and decrease during periods of declining interest rates, net of changes in invested balances. We anticipate that our interest income will increase significantly as a result of the investment of the proceeds from this offering pending the application of the proceeds as described in “Use of Proceeds.”

We transact business in various countries and have exposure to fluctuations in foreign currency exchange rates. Foreign exchange gains and losses arise in the translation of foreign-denominated assets and liabilities, which may result in realized and unrealized gains or losses from exchange rate fluctuations. Since we conduct our business in US dollars and our functional currency is the US dollar, our main foreign exchange exposure, if any, results from changes in the exchange rate between the US dollar and the British pound sterling, the Euro and the Australian dollar.

We invest in certificates of deposit and maintain cash accounts that are denominated in British pounds, Euros and Australian dollars. These foreign denominated certificates of deposit and cash accounts had a balance of $17.0 million as of January 31, 2007 and $16.7 million as of April 30, 2006, compared to our total certificates of deposits and cash account balances of $26.7 million as of January 31, 2007 and $32.4 million as of April 30, 2006. These foreign currency balances are translated at each month end to our functional currency, the US dollar, and any resulting gain or loss is recognized in our results of operations.

In addition, a portion of our operations is conducted through our subsidiaries in countries other than the United States, specifically Ocean Power Technologies Ltd. in the United Kingdom, the functional currency of which is the British pound sterling, and Ocean Power Technologies (Australasia) Pty Ltd. in Australia, the functional currency of which is the Australian dollar. Both of these subsidiaries have foreign exchange exposure that results from changes in the exchange rate between their functional currency and other foreign currencies in which they conduct business. All of our international revenues for the year ended April 30, 2006 were recorded in Euros or British pounds.

We currently do not hedge exchange rate exposure. However, we assess the anticipated foreign currency working capital requirements and capital asset acquisitions of our foreign operations and attempt to maintain a portion of our cash, cash equivalents and certificates of deposit denominated in foreign currencies sufficient to satisfy these anticipated requirements. We also assess the need and cost to utilize financial instruments to hedge currency exposures on an ongoing basis and may hedge against exchange rate exposure in the future.

As of April 30, 2006, we had federal research and development tax credits of $0.5 million and federal net operating losses of approximately $19.5 million to offset future federal taxable income. If not utilized, the credit carryforwards will expire at various dates through 2026, and the net operating loss carryforwards will expire at various dates through 2026. We may not achieve profitability in time to utilize the tax credit and net operating loss carryforwards in full or at all. In addition, the future utilization of our net operating loss carryforwards may be limited based upon changes in ownership, including changes resulting from this offering and the AIM offering in 2003, pursuant to regulations promulgated under the Internal Revenue Code. These limitations may result in the expiration of net operating losses and credits prior to utilization. As discussed in

In fiscal 2004, 2005 and 2006, we sold a portion of our New Jersey state net operating losses and a portion of our New Jersey research and development credits under a program offered by the State of New Jersey, and recognized income tax benefits of approximately $0.1 million in fiscal 2004, $29,000 in fiscal 2005 and approximately $0.1 million in fiscal 2006. Because we believe we are no longer eligible to participate in this program, we do not expect to sell any additional New Jersey state net operating losses or research and development credits in the future.

The following table contains selected unaudited statement of operations information, which serves as the basis of the discussion of our results of operations for the nine months ended January 31, 2006 and 2007:

Revenues of $1.5 million in the first nine months of fiscal 2007 were relatively unchanged from revenues in the same period of fiscal 2006. The change in composition of revenues between the two periods reflected the following factors:

Cost of revenues increased by $0.2 million, or 9%, to $2.1 million in the first nine months of fiscal 2007, as compared to $1.9 million in the same period of fiscal 2006. The decrease in gross margin in the nine months ended January 31, 2007 as compared to the same period of fiscal 2006 was primarily due to an anticipated loss of $0.5 million that was recognized in the nine months ended January 31, 2007 on our contract for a wave power station off the coast of Spain. The loss was recognized based on a change in estimated costs associated with this contract. In addition, $0.2 million of compensation expense was recorded as cost of revenues under Statement of Financial Accounting Standards, or SFAS, No. 123(R), Share-Based Payment, or SFAS 123(R), which requires companies to recognize compensation expense for all stock-based payments to employees. Because we adopted SFAS 123(R) effective May 1, 2006, we did not record similar compensation expense in the first nine months of fiscal 2006.

Product development costs increased $1.5 million, or 56%, to $4.1 million in the nine months ended January 31, 2007, as compared to $2.6 million in the same period of fiscal 2006. The substantial increase in product development costs was primarily attributable to our efforts to increase the power output of our utility PowerBuoy system. In addition, we recorded $0.2 million of compensation expense as product development costs under SFAS 123(R). Because we adopted SFAS 123(R) effective May 1, 2006, we did not record similar compensation expense in the first nine months of fiscal 2006. As a percentage of revenues, product development costs increased to 271% in the nine months ended January 31, 2007 from 179% in the same period in fiscal 2006. We anticipate that our product development costs related to the planned increase in the output of our utility PowerBuoy system will increase significantly over the next several years and that the amount of these expenditures will not necessarily be affected by the level of revenue generated over that time period. Accordingly, comparisons of product development costs as a percentage of revenue may not be meaningful.

Selling, general and administrative costs increased $0.9 million, or 42%, to $3.1 million in the nine months ended January 31, 2007, as compared to $2.2 million in the same period of fiscal 2006. The increase was primarily attributable to an increase of $0.2 million related to additional marketing expenses and consulting costs, $0.3 million in professional fees, and $0.5 million of compensation expense recorded under SFAS 123(R). Because we adopted SFAS 123(R) effective May 1, 2006, we did not record similar compensation expense in the first nine months of fiscal 2006.

Interest income, net remained relatively flat at $1.1 million in the nine months ended January 31, 2007, compared to the same period of fiscal 2006, due to a reduction in the balance of our cash, cash equivalents and certificates of deposit between the two periods of $3.8 million, offset by higher interest rates.

Foreign exchange gain was $1.2 million in the nine months ended January 31, 2007, compared to a foreign exchange loss of $1.5 million in the same period of fiscal 2006. The gain in the first nine months of fiscal 2007 was primarily attributable to the appreciation of the British pound compared to the US dollar.

The following table contains selected statement of operations information, which serves as the basis of the discussion of our results of operations for the years ended April 30, 2005 and 2006: