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ASPEN TECHNOLOGY, INC. AND SUBSIDIARIES INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

As filed with the Securities and Exchange Commission on July 30,September 15, 2010

Registration No. 333-          333-168409

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Amendment No. 1
to

FORM S-1
REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933

ASPEN TECHNOLOGY, INC.
(Exact name of registrant as specified in its charter)

200 Wheeler Road
Burlington, Massachusetts 01803
(781) 221-6400
(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)

Mark E. Fusco
President and Chief Executive Officer
Aspen Technology, Inc.
200 Wheeler Road
Burlington, Massachusetts 01803
(781) 221-6400
(Name, address, including zip code, and telephone number, including area code, of agent for service)

          Approximate date of commencement of proposed sale to public:As soon as practicable after this registration statement becomes effective.

          If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box:    o

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

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

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

          Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

Calculation of Registration Fee

(1)

Estimated solely for the purpose of calculating the registration fee in accordance with Rule 457(c) under the Securities Act of 1933, and based upon the average of the high and low prices of the registrant's common stock on The NASDAQ Global Select Market on July 29, 2010. Includes the offering price attributable to 2,250,000 shares available for purchase by the underwriters to cover over-allotments, if any.

(2)

An aggregate of $8,313 was previously paid by the registrant in connection with the registration of shares under Registration Statement on Form S-1 (Registration No. 333-141959) filed with the Securities and Exchange Commission on April 9, 2007, which registration was terminated on July 31, 2008.

          The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

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SUBJECT TO COMPLETION, DATED JULY 30,SEPTEMBER 15, 2010

The information in this prospectus is not complete and may be changed. The selling stockholders may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities, and the selling stockholders are not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Preliminary Prospectus

15,000,000 Shares

ASPEN TECHNOLOGY, INC.

Common Stock

        The selling stockholders identified in this prospectus, which consist of funds managed by Advent International Corporation, are selling all of the shares of common stock offered by this prospectus and will receive all of the proceeds from this offering. We will not receive any proceeds from the sale of shares of common stock in this offering.

        Our common stock is traded on The NASDAQ Global Select Market under the symbol "AZPN." On July 29,September 14, 2010, the last reported sale price of our common stock on The NASDAQ Global Select Market was $10.92$10.37 per share.

        Investing in our common stock involves a high degree of risk. See "Risk Factors" beginning on page 9.10.

        The underwriters have an option to purchase a maximum of 2,250,000 additional shares of common stock from usthe selling stockholders at the public offering price, less the underwriting discounts and commissions, to cover over-allotment of shares, if any. The underwriters can exercise this option at any time within 30 days from the date of this prospectus.

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

        The underwriters expect to deliver the shares of common stock to purchasers on                        , 2010.

                        , 2010

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        You should rely only on the information contained in this prospectus or in any free writing prospectus we may authorize to be delivered to you. Neither we nor the selling stockholders have authorized anyone to provide you with information different from that contained in this prospectus. This prospectus is not an offer to sell, nor is it seeking an offer to buy, these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that information appearing in this prospectus is accurate as of any date other than the date of this prospectus.

        No action is being taken in any jurisdiction outside the United States to permit a public offering of our common stock or possession or distribution of this prospectus in that jurisdiction. Persons who come into possession of this prospectus in a jurisdiction outside the United States are required to inform themselves about and to observe any restrictions as to this offering and the distribution of this prospectus applicable to that jurisdiction.

        ASPENONE, ASPENTECH, the AspenTech logo, DMCPLUS, HTFS, HYSYS and INFOPLUS.21 are our registered trademarks, and ASPEN BASIC ENGINEERING, ASPEN CAPITAL COST ESTIMATOR, ASPEN COLLABORATIVE DEMAND MANAGER, ASPEN ECONOMIC EVALUATION, ASPEN EXCHANGER DESIGN AND RATING, ASPEN FLEET OPTIMIZER, ASPEN INVENTORY MANAGEMENT & OPERATIONS SCHEDULING, ASPEN OLEFINS SCHEDULER, ASPEN PETROLEUM SCHEDULER, ASPEN PETROLEUM SUPPLY CHAIN PLANNER, ASPEN PIMS, ASPEN PLANNING & SCHEDULING FOR OLEFINS, ASPEN PLANT SCHEDULER, ASPEN RETAILPLUS and ASPEN SUPPLY CHAIN PLANNER are our trademarks. All other trademarks, trade names and service marks appearing in this prospectus are the property of their respective owners.

        Except as otherwise indicated, or as the context may otherwise require, the words "we," "our," "us," and "our company" refer to Aspen Technology, Inc. and its subsidiaries.

        Our fiscal year ends on June 30, and references to a specific fiscal year are to the twelve months ended June 30 of that year. For example, "fiscal 2010" refers to the year ended June 30, 2010.

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PROSPECTUS SUMMARY

        This summary highlights selected information contained in this prospectus. This summary does not contain all the information you should consider before investing in our common stock. Before deciding whether to buy shares of our common stock, you should read the entire prospectus carefully, including "Risk Factors" beginning on page 910 and our consolidated financial statements and related notes beginning on page F-1.

Aspen Technology

        We are a leading global provider of mission-critical process optimization software solutions, which are designed to manage and optimize plant and process design, operational performance, and supply chain planning. Our aspenONE software and related services have been developed specifically for companies in the process industries, including the energy, chemicals, pharmaceuticals, and engineering and construction industries. Customers use our solutions to improve their competitiveness and profitability by increasing throughput and productivity, reducing operating costs, enhancing capital efficiency, and decreasing working capital requirements.

        Our software incorporates our proprietary empirical models of manufacturing and planning processes and reflects the deep domain expertise we have amassed from focusing on solutions for the process industries for nearly 30 years. We have developed our applications to design and optimize processes across three principal business areas: engineering, manufacturing and supply chain. We are a recognized market and technology leader in providing process optimization software for each of these business areas.

        We have more than 1,500 customers globally. Our customers include manufacturers in process industries such as energy, chemicals, pharmaceuticals, consumer packaged goods, power, metals and mining, pulp and paper, and biofuels, as well as engineering and construction firms that help design process manufacturing plants. As of June 30, 2010, our installed base included 19 of the 20 largest petroleum companies, all of the 20 largest chemical companies, and 15 of the 20 largest pharmaceutical companies. Customers outside the United States accounted for a majority of our total revenue in each of fiscal 2007,2010, 2009 and 2008, and 2009, and no single customer represented 10% or more of our total revenue in fiscal 2007, 20082010, 2009 or 2009.2008.

        We have established sustainable competitive advantages based on the breadth, flexibility and return on investment associated with our software offerings, as well as our market leadership position, our extensive process industry expertise and our established, diversified customer base. We consult and collaborate with customers to identify new applications, which leads to innovative, targeted solutions and fosters long-term customer relationships. This approach has helped us develop software solutions that are embedded in our customers' operations and integrated with their core business processes.

        In July 2009 we introduced our aspenONE licensing model under which license revenue is recognized over the term of a license contract. Our new licensing model provides customers with increased access to our applications, and we believe this flexibility will lead to increased usage and revenue over time. Because we previously recognized a substantial majority of our license revenue upon shipment of software, our revenue for fiscal 2010 was significantly less than in the preceding fiscal years. We expect that our revenue will increase as customers renew their licensing arrangements under our new licensing model. We do not expect to recognize levels of revenue comparable to prior fiscal years unless and until a significant majority of our existing license agreements have been renewed under our new licensing model.

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        Our new aspenONE licensing model has not changed the method or timing of our revenue will increase gradually overcustomer billing or cash collections. Our management uses several key financial metrics in operating and assessing our business, including the next severalfollowing:

•

Total term contract value, or TCV, was $1.2 billion as of June 30, 2010 and $1.0 billion as of June 30, 2009. TCV is an estimate of the renewal value of our active portfolio of term license agreements, and it did not include software maintenance and support, or SMS, prior to fiscal years.2010. We estimate that TCV grew by approximately 10% during fiscal 2010 on a comparable "license-only" basis, after removing the SMS portion of TCV as of June 30, 2010.



•

Free cash flow totaled $35.3 million in fiscal 2010, $27.7 million in fiscal 2009 and $61.3 million in fiscal 2008.

Free cash flow is a non-GAAP financial measure. For important information regarding the above metrics, see "—Summary Consolidated Financial Data" and "Management's Discussion and Analysis of Financial Condition and Results of Operations—Key Business Metrics."

Industry Background

        The process industries consist of companies that typically manufacture finished products by applying a controlled chemical process either to a raw material that is fed continuously through the plant or to a specific batch of raw material. The process industries include energy, chemicals,

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pharmaceuticals, consumer packaged goods, power, metals and mining, pulp and paper, and biofuels as well as engineering and construction firms that design process manufacturing plants.

        Process manufacturing is often complex because small changes in the feedstocks used, or to the chemical process applied, can have a significant impact on the efficiency and cost-effectiveness of manufacturing operations. Companies in the process industries have extensive technical requirements and need a combination of software, services and domain expertise to help design, operate and manage manufacturing environments. The unique characteristics associated with process manufacturing create special demands for business applications that frequently exceed the capabilities of generic or non-process manufacturing software.

        In addition to the technical requirements associated with the process industries, several industry trends are driving the growing complexity of these industries:

•

Globalization of markets.  Growing demand and available feedstock in emerging markets are leading process companies to design, build and operate plants in China, India, Russia, Latin America and the Middle East.



•

Volatile markets.  Unpredictable commodity markets are straining the manufacturing and supply chain operations of process manufacturers, which must react quickly to frequent changes in the prices and availability of feedstock and in the pricing of finished products.



•

Increased margin pressure.  Increasingly competitive global markets are driving process companies to design more efficient plants while increasing throughput and reducing costs at existing plants.



•

Shrinking engineering workforce.  Decreasing numbers of chemical engineers in mature markets are driving process companies to adopt technology solutions that can capture knowledge and automate tasks.



•

Environmental and safety regulations.  Expanding regulatory requirements are presenting compliance challenges for process companies, which face heightened scrutiny because of the environmental, safety and other implications of their products and manufacturing processes.

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Market Opportunity

        Technology solutions historically have played a major role in helping companies in the process industries improve their manufacturing productivity. In the 1980s process manufacturers implemented distributed control systems, or DCS, to automate the management of plant hardware. In the 1990s they adopted enterprise resource planning, or ERP, systems to streamline back office functions and interact with DCS. Many process manufacturers have implemented both DCS and ERP systems but have realized that these systems are incapable of optimizing what is produced, how it is produced or where it is produced.

        Process optimization software addresses the gap between DCS and ERP systems by optimizing the manufacturing process itself: how the process is run and the economics of that process. By connecting DCS and ERP systems with intelligent, dynamic applications, process optimization software allows a manufacturer to make better, faster economic decisions closer to the process. This software can optimize a manufacturing environment by, for example, incorporating process manufacturing domain knowledge, supporting real-time decision making, and providing the ability to forecast and simulate potential actions. Furthermore, these solutions can optimize the supply chain by helping a manufacturer to understand the operating conditions in each plant, which enables a manufacturer to decide where to manufacture products based on economics.

        The market for engineering, manufacturing and supply chain process optimization software and services for the energy, chemicals and pharmaceuticals industries was $2.4 billion in 2008, based on

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information from reports issued in 2009 by ARC Advisory Group. More specifically, based on this information, it is estimated that:

•

the engineering market was $443 million in 2008 and will grow 8% annually through 2013;



•

the manufacturing market was $1.7 billion in 2008 and will grow 12% annually through 2013; and



•

the supply chain market was $279 million in 2008 and will grow 5% annually through 2013.

aspenONE Solutions

        We provide integrated process optimization software solutions designed and developed specifically for the process industries. We also offer customer support, professional services and training services. Our aspenONE software applications are organized into two suites, which are centered on our principal business areas of engineering, manufacturing and supply chain:

•

aspenONE Engineering.  Our engineering software is used on an engineer's desktop to design new plants, re-design existing plants, and simulate and optimize plant processes.



•

aspenONE Manufacturing and Supply Chain.  Our manufacturing software is designed to optimize day-to-day processing activities, enabling process manufacturers to make better, more profitable decisions and to improve plant performance. Our supply chain management software is designed to enable process manufacturers to reduce inventory levels, increase asset efficiency and optimize supply chain decisions.

        The key benefits of our aspenONE solutions include:

        Broad and comprehensive software suites.    We are the only software provider that has developed comprehensive suites of software applications addressing the engineering, manufacturing and supply chain requirements of process manufacturers.

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        Mission-critical, integrated software solutions.    aspenONE provides a standards-based framework that integrates applications, data and models within each of our software suites. Process manufacturers seeking to improve their mission-critical business operations can use our integrated applications to support real-time decision-making—both for individual production facilities and across multiple sites.

        Flexible commercial model.    Our new aspenONE licensing model provides customersa customer with access to all of the applications within a licensed aspenONE suite, enabling themthe customer to use those applications whenever required and to test themexperiment with different applications to best solve and optimize whatever critical business challenges the customers face. Customerscustomer faces. The customer can easily increase theirits usage of our software as theirits business requirements evolve, without disrupting theirits business processes.

        Hardware-independent technology.    Our software can be easily integrated and used with equipment manufactured by any major process manufacturing hardware vendor. Because of our hardware-independent approach, customers can use our software to create a unified view of their operations across plants with hardware from different vendors.

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Our Competitive Strengths

        We believe our key competitive advantages include, in addition to the comprehensive breadth of our integrated software solutions and the flexibility of our new aspenONE licensing model, the following:

        Market leadership.    We are a leader in each of the markets addressed by our software. Based on information presented in reports of ARC Advisory Group relating to performance in 2008, in our core process manufacturing industries of energy, chemicals and pharmaceuticals we ranked:

•

#1 in the market addressed by our engineering software;



•

#2 in the market addressed by our manufacturing software; and



•

#1 in the market addressed by our supply chain software.

        Industry-leading innovation based on substantial process expertise.    Over the past 30 years, we have designed a number of major process engineering advances considered to be industry-standard applications. As of June 30, 2010, approximately 50% of our software development personnel had degrees in chemical engineering or a similar discipline, which helps us address the specific challenges of the process industries.

        Rapid, high return on investment.    Many customers purchase our software because they believe it will provide rapid, demonstrable and significant returns on their investment. For some customers, cost reductions in the first year following installation have exceeded the total cost of our software. For many customers, even a relatively small improvement in productivity can generate substantial recurring benefits due to the large production volumes and limited profit margins typical in process industries.

        Established, diversified customer base.    As of June 30, 2010, our installed base of more than 1,500 customers included 19 of the 20 largest petroleum companies, all of the 20 largest chemical companies, and 15 of the 20 largest pharmaceutical companies. We consult and collaborate with customers to identify new applications, which leads to innovative, targeted solutions and fosters long-term customer relationships.

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Growth Strategy

        Our objective is to further establish and extend our position as a leading global provider of process optimization software and related services to the process industries. We intend to build upon our market and technology leadership position by pursuing the following:

•

continue to provide innovative, market-leading solutions;



•

further penetrate our existing customer base;



•

expand our presence in emerging markets; and



•

extend our vertical reach and indirect sales channel.

Risk Factors

        Our business is subject to a number of risks that you should understand before deciding to invest in our common stock. These risks are discussed more fully in "Risk Factors" beginning on page 9,10, and they include:

•

we depend on our aspenONE software for a substantial portion of our revenue, and our business will suffer if demand for, or usage of, our software declines for any reason or if existing customers do not renew under our new aspenONE licensing model;

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•

our operating resultsrevenue and net income for fiscal 2010 have been,were, and for the foreseeable future will be, adversely affected by the transition to our new licensing model;



•

in preparing our consolidated financial statements for fiscal 2009,2010, our management identified fourtwo material weaknesses in our internal control over financial reporting, and our failure to remedy these or other material weaknesses could result in material misstatements in our financial statements and the loss of investor confidence in our reported financial information;



•

arbitration and litigation involving a former reseller in the Middle East may subject us to substantial damages and expenses;



•

our operating results may suffer if customers in the energy, chemicals, engineering and construction, or pharmaceuticals industries experience an economic downturn or other adverse events; and



•

unfavorable economic and market conditions and a lessening demand in the market for process optimization software could adversely affect our operating results.

Corporate Information

        We were incorporated in Massachusetts in 1981 and reincorporated in Delaware in 1998. Our principal executive offices are located at 200 Wheeler Road, Burlington, Massachusetts 01803, and our telephone number at that address is (781) 221-6400. Our website address iswww.aspentech.com. The information on our website is not part of this prospectus.

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The Offering

        The number of shares of common stock outstanding as of June 30,September 1, 2010 excludes:

•

630,640 shares issuable upon the exercise of warrants outstanding and exercisable as of June 30, 2010, at an exercise price of $3.33 per share;



•

5,266,3545,247,039 shares issuable upon the exercise of options outstanding and vested as of June 30,September 1, 2010, at a weighted average exercise price of $7.11$6.94 per share;



•

129,5161,057,529 shares issuable upon the exercise of options outstanding but not vested as of June 30,September 1, 2010, at a weighted average exercise price of $10.24$10.84 per share;



•

1,512,2632,214,431 shares issuable upon the vesting of restricted stock units outstanding as of June 30,September 1, 2010, without payment of an exercise price; and



•

8,348,8036,348,233 shares authorized and available as of June 30,September 1, 2010, for future issuance under our equity compensation plans.

        Except as otherwise noted, the information in this prospectus assumes no exercise by the underwriters of their over-allotment option.

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Summary Consolidated Financial Data

        The following tables summarize our consolidated financial data for the periods presented. You should read these data together with the consolidated financial statements beginning on page F-1, as well as "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the other financial information included elsewhere in this prospectus.

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        In the following table, as adjusted data reflect the estimated offering expenses we expect to incur in connection with this offering.

        Following the introduction of our new aspenONE licensing model, management focuses on certain metrics, including the key metrics set forth below, to assist in operating and assessing our business. We believe these metrics are useful to investors in evaluating our operating performance following the introduction of our new licensing model. None of these metrics should be considered as an alternative to any measure of financial performance calculated in accordance with U.S. generally accepted accounting principles or GAAP, including net cash provided by operating activities, which is the GAAP financial measure most directly comparable to free cash flow. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Key Business Metrics."

(1)

Software maintenance and support, or SMS, was not included as part of our term license arrangements prior to fiscal 2010, and no SMS was included in estimated TCV as of June 30, 2009. For comparability purposes, we estimated "license-only" TCV growth for fiscal 2010 by removing the SMS portion of TCV as of June 30, 2010. On this comparable "license-only" basis, we estimate that TCV grew by approximately 10% during fiscal 2010. Overall, we estimate that TCV, with SMS included as of June 30, 2010, increased by approximately 17% during fiscal 2010.

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For these purposes:

•

Total term contract value,or TCV, is an estimate of the renewal value, as of a specific date, of our active portfolio of term license agreements. TCV is calculated by multiplying the terminal annual payment for each active term license agreement by the original length of the existing license term, and then aggregating this amount for all active term license agreements. TCV includes the value of SMS for license agreements under our new aspenONE licensing model, in which SMS is committed for the entire license term. TCV does not include any amounts for perpetual licenses, professional services, training or standalone renewal SMS.



•

Bookings represent the amount of contractually committed subscription and software fees, including any bundled software maintenance and support or SMS. Bookings do not include (a) the amount of fees for professional services, training and standalone renewal SMS or (b) the amount of subscription and software fees remaining under existing license agreements that are replaced prior to the scheduled expiration date.



•

Billings backlog represents the aggregate value of uninvoiced bookings from prior and current periods. Billings backlog is not reflected on our consolidated balance sheets.

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RISK FACTORS

        Investing in our common stock involves a high degree of risk. You should carefully consider the risks and uncertainties described below before purchasing our common stock. The risks and uncertainties described below are not the only ones facing our company. Additional risks and uncertainties may also impair our business operations. If any of the following risks actually occurs, our business, financial condition, results of operations or cash flows would likely suffer. In that case, the trading price of our common stock could fall, and you may lose all or part of your investment in our common stock.

Risks Related to Our Business

We depend on our aspenONE software for a substantial portion of our revenue, and our business will suffer if demand for, or usage of, our software declines for any reason or if existing customers do not renew under our new aspenONE licensing model.

        Our aspenONE suites account for a significant majority of our license revenue and will continue to do so for the foreseeable future. If demand for, or usage of, our software declines for any reason or if existing customers do not renew under our new aspenONE licensing model, our revenue would decline and our operating results would suffer. As a result, our revenue could be adversely affected by:

•

any decline in demand for or usage of our aspenONE suites;



•

the failure of our aspenONE suites to achieve continued market acceptance;



•

the introduction of products and technologies that serve as a replacement or substitute for, or represent an improvement over, our aspenONE suites;



•

technological innovations that our aspenONE suites do not address; and



•

our inability to release enhanced versions of our aspenONE suites on a timely basis.

        In July 2009 we introduced our aspenONE licensing model under which we recognize license revenue over the term of a license contract. Our future success depends substantially on our customers' acceptance of our new licensing model. We are not able to predict the rate at which customers will renew under our new licensing model and therefore cannot predict the timing or amount of our future revenue or profitability. If customers fail to renew under our new licensing model, we may lose customers, which would negatively impact our financial performance. We intend to expend significant resources to continue to improve our aspenONE solutions and to train our customers in using our solutions, but the successful development of our new licensing model cannot be predicted and we cannot guarantee we will succeed in these goals. Furthermore, customers may elect to continue to purchase our applications on a point product basis, which could limit our ability to grow our business successfully.

Our revenue and net income for fiscal 2010 have been,were, and for the foreseeable future will be, adversely affected by the transition to our new aspenONE licensing model.

        Our new aspenONE licensing model, which we introduced in July 2009, provides customers with access to all of the applications within the aspenONE suite or suites they license and includes software maintenance and support, or SMS, for the term of the license contract. Prior to July 2009 we primarily recognized license revenue "upfront," upon shipment of software, on a net present value basis in the period in which a license contract was signed, not over the license term.

        As a result of the transition to our new aspenONE licensing model, our revenue for 2010 was significantly less than the level achieved in the preceding years and we expect our license revenue will remain below that level for several more years. Our new licensing model makes it difficult for us to increase our license revenue rapidly through additional bookings in a period, as license revenue from

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new customers will be recognized over the applicable license term. Similarly, the full effect of a decline in bookings in any period would not be fully recognized in our revenue for that period, but would

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negatively affect revenue in subsequent quarters. Moreover, the marked decrease in revenue levels following our introduction of our new licensing model will not result in, or be accompanied by, a corresponding reduction in operating costs.expenses. As a result, the change to our new licensing model will result in our reporting not only significantly lower revenue but also large operating losses for at least the near term and potentially several years. A number of the measures of financial performance calculated in accordance with U.S. generally accepted accounting principles or GAAP and typically considered by investors for technology companies like ours will be of limited value in assessing our performance, growth and financial condition for the foreseeable future. Our announcement of GAAP-based operating results, as well as our lack of visibility into future operating results, may have a significant adverse effect on the price of our common stock.

In preparing our consolidated financial statements for fiscal 2009,2010, our management identified fourtwo material weaknesses in our internal control over financial reporting, and our failure to remedy these or other material weaknesses could result in material misstatements in our financial statements and the loss of investor confidence in our reported financial information.

        Our management is responsible for establishing and maintaining adequate internal control over our financial reporting, as defined in Rule 13a-15(f) under the Securities Exchange Act. Our management identified fourtwo material weaknesses in our internal control over financial reporting as of June 30, 2009.2010. A material weakness is defined as a deficiency, or combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.

        The material weaknesses identified by management as of June 30, 20092010 consisted of inadequate and ineffective:

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monitoring controls;



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controls over the periodic financial close process;



•

ineffective controls over income tax accounting and disclosure;disclosure and



•

controls over the recognition of professional services revenue.

As a result of these material weaknesses, our management concluded as of June 30, 20092010 that our internal control over financial reporting was not effective based on criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission inInternal Control—An Integrated Framework (September 1992).

        We have been implementing and continue to implement remedial measures designed to address these material weaknesses. We cannot be certain that the measures we have taken since these restatements are effective or will ensure that restatements will not occur in the future. If these remedial measures are insufficient to address these material weaknesses, or if additional material weaknesses or significant deficiencies in our internal control are discovered or occur in the future, our consolidated financial statements may contain material misstatements and we could be required to restate our prior period financial results. We restated our consolidated financial statements for each of the fiscal years from fiscal 2002 to fiscal 2007 and for the first quarter of fiscal 2008. Any future restatement of consolidated financial statements could place a significant strain on our internal resources and harm our operating results. Further, any additional or unremedied material weakness may preclude us from meeting our reporting obligations on a timely basis. We have previously not been in compliance with SEC reporting requirements and NASDAQ listing requirements. As a result of the restatements of our consolidated financial statements, we did not maintain our status as a timely filer with the SEC during the period from September 2007 to November 9, 2009 and from November 10,16, 2009 to December 21, 2009, and as a result our common stock was delisted from The NASDAQ Global Select Market in February 2008 and not relisted until February 2010. If we again fail to remain in compliance with SEC

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reporting requirements and NASDAQ continued listing requirements, there may be a material adverse effect on our business and the market for our common stock. If we were required to restate our consolidated financial statements, we could be subject to class action litigation and SEC proceedings and could incur monetary

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judgments, penalties or other sanctions that could adversely affect our financial condition and could cause our stock price to decline.

        Any failure to address the identified material weaknesses or any additional material weaknesses in our internal control could also adversely affect the results of the periodic management evaluations regarding the effectiveness of our internal control over financial reporting that are required to be included in our annual reports on Form 10-K. Internal control deficiencies could also cause investors to lose confidence in our reported financial information. We can give no assurance that the measures we have taken and plan to take in the future will remediate the material weaknesses identified or that any additional material weaknesses or additional restatements of financial results will not arise in the future due to a failure to implement and maintain adequate internal control over financial reporting or circumvention of these controls. In addition, even if we are successful in strengthening our controls and procedures, in the future those controls and procedures may not be adequate to prevent or identify irregularities or errors or to facilitate the fair presentation of our consolidated financial statements.

Arbitration and litigation involving a former reseller in the Middle East may subject us to substantial damages and expenses.

        Prior to October 6, 2009, we had an exclusive reseller relationship covering certain countries in the Middle East with AspenTech Middle East W.L.L., a Kuwaiti corporation (now known as Advanced Technology Middle East W.L.L.) that we refer to below as ATME. Under the reseller agreement, we had the right to terminate for, among other things, a material breach in the event of ATME's willful misconduct or fraud. Effective October 6, 2009, we terminated the reseller relationship for material breach by ATME, based on certain actions of ATME.

        On November 2, 2009, ATME commenced an action in the Queen's Bench Division (Commercial Court) of the High Court of Justice (England & Wales) captioned In The Matter Of An Intended Arbitration Between AspenTech Middle East W.L.L. and Aspen Technology, Inc., 2009 Folio 1436, seeking preliminary injunctive relief restraining us from taking any steps to impede ATME from serving as our exclusive reseller in the countries covered by the reseller agreement with ATME. We filed evidence in opposition to that request for relief on November 12, 2009. At a hearing on November 13, 2009, the court dismissed ATME's application for preliminary injunctive relief. The court sealed an Order to this effect on November 23, 2009, and further ordered that ATME pay our costs of claim.

        Relatedly, on November 11, 2009, we filed a request for arbitration against ATME in the International Court of Arbitration of the International Chamber of Commerce, captioned Aspen Technology, Inc. v. AspenTech Middle East W.L.L., Case No. 16732/VRO. Our request for arbitration asserted claims against ATME seeking a declaration that ATME committed a material breach of our agreement and that our termination of our agreement was lawful, and seeking damages for ATME's willful misconduct in connection with the reseller relationship. On November 18, 2009, ATME filed its answer to that request for arbitration and asserted counterclaims against us seeking a declaratory judgment that we unlawfully terminated our agreement with ATME and seeking damages for breach of contract by reason of our purported unlawful termination of our agreement. Our reply to those counterclaims was filed on December 18, 2009.

        We expect a determination to be made in the second half of calendar yearfiscal 2011 with respect to the pending arbitration. However, we can provide no assurance as to the actual timing or outcome of the arbitration. In general, neither party will have the ability to appeal the determination reached. Regardless of the outcome, the proceedings may result in significant legal expenses and may require significant attention and resources of management, all of which could result in losses and damages that have a material adverse effect on our business. The reseller agreement with ATME contained a

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provision whereby we could be liable for a termination fee if the agreement were terminated other than for material breach. This fee is to be calculated based on a formula contained in the reseller agreement

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that we believe was originally developed based on certain assumptions about the future financial performance of ATME, as well as ATME's actual financial performance. Based on the formula and the financial information provided to us by ATME, which we have not yet verified independently, a recent calculation based on the formula would result in a termination fee of between $60 million and $77 million. Under the terminated reseller agreement, no termination fee is owed on termination for material breach. If we are found to have breached the terms of our agreement with ATME, we could be found liable for the termination fee, the amount of which may be greater or less than the number indicated above. If we are found liable, we would incur damages that could have a material adverse effect on our cash flow and cash position.

        On March 11, 2010, a Kuwaiti entity (known as ATME Group and affiliated with ATME) filed a lawsuit in a Kuwaiti court naming as defendants ATME, us and a reseller newly appointed by us in Kuwait. In this lawsuit, ATME Group claims that it was an exclusive reseller for ATME in Kuwait and that it therefore is entitled to damages resulting from purported customer contracts in Kuwait.

Our operating results may suffer if customers in the energy, chemicals, engineering and construction, or pharmaceuticals industries experience an economic downturn or other adverse events.

        We derive a majority of our revenue from companies in the energy, chemicals, engineering and construction, and pharmaceutical industries. Accordingly, our future success depends upon the continued demand for process optimization software and related services by companies in these process industries. These industries are highly cyclical and highly reactive to the price of oil, as well as general economic conditions. Adverse changes in these industries could and have caused delays and reductions in information technology spending by our customers, which could lead to reductions, delays, postponements or cancellations of customer purchases of our products and services, particularly the aspenONE Manufacturing and Supply Chain suite, and in turn could negatively impact our operating results.

        Because of the nature of their products and manufacturing processes, companies in these process industries are subject to heightened risk of adverse or even catastrophic environmental, safety and health accidents or incidents, such as the recent oil spill in the U.S. Gulf of Mexico. Further, our customers are often subject to ever-changing standards and regulations, and the global nature of their operations can subject them to numerous regulatory regimes. Legislation or regulations regarding these areas may require us to make rapid changes in our products and services, and our inability to effect those changes could adversely impact our revenue, operating margins and other operating results. Any of the foregoing types of events that affects our customers may adversely impact their operations and information technology spending, which could have an adverse effect on our operating results.

        In addition, in the past, worldwide economic downturns and pricing pressures experienced by energy, chemical, pharmaceutical and other process industries have led to consolidations and reorganizations. These downturns, pricing pressures and reorganizations have caused delays and reductions in capital and operating expenditures by many of these companies. These delays and reductions have reduced demand for products and services like ours.

        In addition, as the global economy deteriorated in 2009, some of our customers elected to change from paying for term licenses upfront to paying in installments over the contract term, which deferred our receipt of cash from those customers. A recurrence of these industry patterns, including any recurrence that may occur in connection with current global economic events, as well as general domestic and foreign economic conditions and other factors that reduce spending by companies in these industries, could harm our operating results in the future. There is no assurance that customers may not seek bankruptcy or other similar relief from creditors, fail to pay amounts due to us, or pay those amounts more slowly, any of which could adversely affect our results of operations.

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Unfavorable economic and market conditions or a lessening demand in the market for process optimization software could adversely affect our operating results.

        Our business is influenced by a range of factors that are beyond our control and difficult or impossible to predict. If the market for process optimization software grows slowermore slowly than we anticipate, demand for our products and services could decline and our operating results could be impaired. Further, the state of the economy, which deteriorated in the recent broad recession, may deteriorate further in the future. Our operating results may be adversely affected by unfavorable global economic and market conditions as well as a lessening demand for process optimization software generally. Customer demand for our products is intrinsically linked to the strength of the economy. If weakness in the economies of the United States and other countries persists, many customers may delay or reduce technology purchases. This could result in reductions in sales of our products, longer sales cycles, slower adoption of new technologies, increased price competition or reduced use of our products by our customers. We will lose revenue if demand for our products is reduced because potential customers experience weak or deteriorating economic conditions, catastrophic environmental or other events and our business, results of operations, financial condition and cash flow from operations would likely be adversely affected.

The majority of our revenue and an increasing percentage of our operations are attributable to operations outside the United States, and our operating results therefore may be materially affected by the economic, political, regulatory and other risks of foreign operations.

        As of June 30, 2010, we had 26 offices in 22 countries. We sell our products primarily through a direct sales force located throughout the world. In the event that we are unable to adequately staff and maintain our foreign operations, we could face difficulties managing our international operations.

        Customers outside the United States accounted for a significant amount of our total revenue in fiscal 2007, 2008, and2010, 2009 and in the nine months ended March 31, 2010.2008. We anticipate that revenue from customers outside the United States will continue to account for a significant portion of our total revenue for the foreseeable future. Our operations outside the United States are subject to additional risks, including:

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unexpected changes in regulatory requirements, exchange rates, tariffs and other barriers;



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political and economic instability and possible nationalization of property by governments without compensation to the owners;



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less effective protection of intellectual property;



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requirements of foreign laws and other governmental controls;



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difficulties and delays in translating products and product documentation into foreign languages;



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difficulties and delays in negotiating software licenses compliant with accounting revenue recognition requirements in the United States;



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difficulties in collecting trade accounts receivable in other countries;



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adverse tax consequences; and



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the challenges of handling legal disputes in foreign jurisdictions.

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Competition from software offered by current competitors and new market entrants, as well as from internally developed solutions by our customers, could adversely affect our ability to sell our software products and related services and could result in pressure to price our products in a manner that reduces our margins.

        Our markets in general are highly competitive and differ among our principal product areas: engineering, manufacturing, and supply chain management. Our engineering software competes with

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products of businesses such as ABB Ltd., Chemstations, Inc., Honeywell International, Inc., Invensys plc, KBC Advanced Technologies plc, and Shell Global Solutions International BV. Our manufacturing software competes with products of companies such as ABB Ltd., Honeywell International, Inc., Invensys plc, OSIsoft, Inc., Rockwell Automation, Inc., Siemens AG, SAP AG and Yokogawa Electric Corporation. Our supply chain management software competes with products of companies such as JDA Software Group, Inc., Oracle Corporation and SAP AG. In addition, we face challenges in selling our solutions to large companies in the process industries that have internally developed their own proprietary software solutions.

        Many of our current and potential competitors have greater financial, technical, marketing, service and other resources than we have. As a result, these companies may be able to offer lower prices, additional products or services, or other incentives that we cannot match or offer. These competitors may be in a stronger position to respond more quickly to new technologies and may be able to undertake more extensive marketing campaigns. We believe they also have adopted and may continue to pursue more aggressive pricing policies and make more attractive offers to potential customers, employees and strategic partners. For example, some competitors may be able to initiate relationships through sales and installations of hardware and then seek to expand their customer relationships by offering process optimization software at a discount. In addition, many of our competitors have established, and may in the future continue to establish, cooperative relationships with third parties to improve their product offerings and to increase the availability of their products in the marketplace. Competitors with greater financial resources may make strategic acquisitions to increase their ability to gain market share or improve the quality or marketability of their products.

        Competition could seriously impede our ability to sell additional software products and related services on terms favorable to us. Businesses may continue to enhance their internally developed solutions, rather than investing in commercial software such as ours. Our current and potential commercial competitors may develop and market new technologies that render our existing or future products obsolete, unmarketable or less competitive. In addition, if these competitors develop products with similar or superior functionality to our products, we may need to decrease the prices for our products in order to remain competitive. If we are unable to maintain our current pricing due to competitive pressures, our margins will be reduced and our operating results will be negatively affected. We cannot assure you that we will be able to compete successfully against current or future competitors or that competitive pressures will not materially adversely affect our business, financial condition and operating results.

If we fail to develop new software products, enhance existing products and services, or penetrate new vertical markets, we will be unable to implement our growth strategy successfully and our business could be seriously harmed.

        The maintenance and extension of our market leadership and our future growth is largely dependent upon our ability to develop new software products that achieve market acceptance with acceptable operating margins. Enterprises are requiring their application software vendors to provide greater levels of functionality and broader product offerings. Moreover, our industry is characterized by rapidly changing technologies and evolving industry standards and operating platforms. Competitors continue to make rapid technological advances in computer hardware and software technology and frequently introduce new products, services and enhancements. We must continue to enhance our current product line and develop and introduce new products and services that keep pace with

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increasingly sophisticated customer requirements and the technological developments of our competitors. Our business and operating results could suffer if we cannot successfully respond to the technological advances of competitors, or if our new products or product enhancements and services do not achieve market acceptance.

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        Under our business plan, we are implementing a product strategy that unifies our software solutions under the aspenONE brand with differentiated aspenONE vertical solutions targeted at specific process industry segments. We cannot assure you that our product strategy will result in products that will meet market needs and achieve significant market acceptance. If we fail to introduce new products that meet the demands of our customers or our target markets, or if we fail to penetrate new vertical markets in the process industries, our revenue will likely grow at a slower rate than we anticipate and our financial condition could suffer.

Defects or errors in our software products could harm our reputation, impair our ability to sell our products and result in significant costs to us.

        Our software products are complex and may contain undetected defects or errors. We have not suffered significant harm from any defects or errors to date, but we have from time to time found defects in our products and we may discover additional defects in the future. We may not be able to detect and correct defects or errors before releasing products. Consequently, we or our customers may discover defects or errors after our products have been implemented. We have in the past issued, and may in the future need to issue, corrective releases of our products to remedy defects or errors. The occurrence of any defects or errors could result in:

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lost or delayed market acceptance and sales of our products;



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delays in payment to us by customers;



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product returns;



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injury to our reputation;



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diversion of our resources;



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legal claims, including product liability claims, against us;



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increased service and warranty expenses or financial concessions; and



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increased insurance costs.

Defects and errors in our software products could result in an increase in service and warranty costs or claims for substantial damages against us.

We are subject to a number of lawsuits and disputes arising out of the conduct of our business.

        We are subject to a number of lawsuits and disputes arising out of the conduct of our business. Resolution of these matters can be prolonged and costly, and the ultimate results or judgments are uncertain due to the inherent uncertainty in litigation and other proceedings. Moreover, our potential liabilities are subject to change over time due to new developments, changes in settlement strategy or the impact of evidentiary requirements, and we may be required to pay damage awards or settlements that could have a material adverse effect on our results of operations, cash flows and financial condition.

        In March 2006, we settled class action litigation, including related derivative claims, arising out of our originally filed consolidated financial statements for fiscal 2000 through 2004, the accounting for which we restated in March 2005. Certain members of the class (representing 1,457,969 shares of common stock, or less than 1% of the shares putatively purchased during the class action period) opted

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out of the settlement and had the right to bring their own state or federal law claims against us, referred to as "opt-out" claims. Opt-out claims were filed on behalf of the holders of approximately 1.1 million of such shares. One of these actions was settled and three were dismissed. The claims in the remaining actions (described below) include claims against us and one or more of our former officers alleging securities and common law fraud, breach of contract, deceptive practices and/or rescissory

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damages liability, based on the restated results of one or more fiscal periods included in our restated consolidated financial statements referenced in the class action.

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Herbert G. and Eunice E. Blecker, et al. v. Aspen Technology, Inc., et al., filed in June 2006 in the Business Litigation Session of the Massachusetts Superior Court for Suffolk County and docketed as Civ. A. No. 06-2357-BLS1, was an opt-out claim asserted by persons who received 248,411 shares of our common stock in an acquisition. Fact discovery in this action closed in July 2008, and a non-jury trial was conducted in November 2009. In January 2010, the court issued its order granting judgment in our favor and dismissing the case. In February 2010, the plaintiffs filed a notice of appeal of the judgment.



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380544 Canada, Inc., et al. v. Aspen Technology, Inc., filed on February 15, 2007 in the federal district court for the Southern District of New York and docketed as Civ. A. No. 1:07-cv-01204-JFK in that court, is a claim asserted by persons who purchased 566,665 shares of our common stock in a private placement. Certain motions to dismiss filed by other defendants were resolved on May 5, 2009, and discovery is in process. The claims in the 380544 Canada action are for damages totaling at least $4.0 million, not including claims for attorneys' fees. We plan to defend the 380544 Canada action vigorously.

        We can provide no assurance as to the outcome of these cases or the likelihood of the filing of additional opt-out claims, and these claims may result in judgments against us for significant damages. Regardless of the outcome, such litigation has resulted in the past, and may continue to result in the future, in significant legal expenses and may require significant attention and resources of management, all of which could result in losses and damages that have a material adverse effect on our business.

We may be subject to significant expenses and damages because of pending liability claims and other claims related to our products and services.

        The sale and implementation of certain of our software products and services, particularly in the areas of advanced process control and supply chain management, entail the risk of product liability claims and associated damages. Our software products and services are often integrated with our customers' networks and software applications and are used in the design, operation and management of manufacturing and supply chain processes at large facilities, often for mission critical applications.

        Any errors, defects, performance problems or other failures of our software could result in significant liability to us for damages or for violations of environmental, safety and other laws and regulations. Our software products and implementation services could give rise to warranty and other claims. We are unable to determine whether resolution of any of these matters will have a material adverse impact on our financial position, cash flows or results of operations, or, in many cases, reasonably estimate the amount of the loss, if any, that may result from the resolution of these matters.

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        Our agreements with customers generally contain provisions designed to limit our exposure to potential product liability claims. It is possible, however, that the limitation of liability provisions in our agreements may not be effective as a result of federal, foreign, state or local laws or ordinances or unfavorable judicial decisions. A substantial product liability judgment against us could materially and adversely harm our operating results and financial condition. Even if our software is not at fault, a product liability claim brought against us could be time-consuming, costly to defend and harmful to our operations.

Implementation of some of our products can be difficult and time-consuming, and customers may be unable to implement those products successfully or otherwise achieve all of the potential benefits of the products.

        Some of our scheduling, production management and execution, and supply chain products must integrate with the existing computer systems and software programs of our customers. This process can

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be complex, time-consuming and expensive. As a result, some customers may have difficulty in implementing those products or be unable to implement them successfully or otherwise achieve the products' potential benefits. Delayed or ineffective implementation of those software products or related services may limit our revenue or may result in customer dissatisfaction, harm to our reputation and customer unwillingness to pay the fees associated with these products.

We may suffer losses on fixed-price professional service engagements.

        We undertake a portion of our professional service engagements on a fixed-price basis. Under these types of engagements, we bear the risk of cost overruns and inflation. In the past we have experienced cost overruns, which on occasion have been significant. Should the number of our fixed-price engagements increase in the future, we may experience additional cost overruns that could have a pronounced impact on our operating results.

Fluctuations in foreign currency exchange rates could result in declines in our reported revenue and operating results.

        In fiscal 2009, 14%2010, 24% of our total revenue was denominated in a currency other than the U.S. dollar. In addition, certain of our operating costsexpenses incurred outside the United States are denominated in currencies other than the U.S. dollar. Our reported revenue and operating results are subject to fluctuations in foreign exchange rates. Foreign currency risk arises primarily from the net difference between non-U.S. dollar receipts from customers outside the United States and non-U.S. dollar operating costsexpenses for subsidiaries in foreign countries. Currently, our largest exposures to foreign exchange rates exist primarily with the Euro, Pound Sterling, Canadian dollar and Japanese Yen against the U.S. dollar. Over recent months, the value of foreign currencies against the U.S. dollar has fluctuated dramatically. Since late fiscal 2008, we have not entered into derivative financial instruments, such as forward currency exchange contracts, intended to manage the volatility of these market risks. We cannot predict the impact of foreign currency fluctuations, and foreign currency fluctuations in the future may adversely affect our revenue and operating results. Any hedging policies we may implement in the future may not be successful, and the cost of those hedging techniques may have a significant negative impact on our operating results.

If we fail to comply or are deemed to have failed to comply, with our ongoing Federal Trade Commission, or FTC, consent decree, our business may suffer.

        In December 2004, we entered into a consent decree with the FTC with respect to a civil administrative complaint filed by the FTC in August 2003 alleging that our acquisition of Hyprotech in May 2002 was anticompetitive in violation of Section 5 of the Federal Trade Commission Act and Section 7 of the Clayton Act. In July 2009, we announced that the FTC closed an investigation relating to the alleged violations of the decree and issued an order modifying the consent decree, which

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became final in August 2009. We are subject to ongoing compliance obligations under the FTC consent decree. There is no assurance that the actions required by the FTC's modified order and related settlement with Honeywell will not require significant attention and resources of management, which could have a material adverse effect on our business. Further, if we fail to comply, or are deemed to have failed to comply, with such consent decree, our business may suffer.

We may not be able to protect our intellectual property rights, which could make us less competitive and cause us to lose market share.

        We regard our software as proprietary. Our strategy is to rely on a combination of copyright, patent, trademark and trade secret laws in the United States and other jurisdictions, and to rely on license and confidentiality agreements and software security measures to further protect our proprietary technology and brand. We have obtained or applied for patent protection with respect to some of our

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intellectual property, but generally do not rely on patents as a principal means of protecting our intellectual property. We have registered or applied to register some of our trademarks in the United States and in selected other countries. We generally enter into non-disclosure agreements with our employees and customers, and historically have restricted third-party access to our software source code and licenses, which we regard as proprietary information. In certain cases, we have provided copies of source code to customers for the purpose of special product customization or have deposited copies of the source code in third-party escrow accounts as security for ongoing service and license obligations. In these cases, we rely on non-disclosure and other contractual provisions to protect our proprietary rights.

        The steps we have taken to protect our proprietary rights may not be adequate to deter misappropriation of our technology or independent development by others of technologies that are substantially equivalent or superior to our technology. Our intellectual property rights may expire or be challenged, invalidated or infringed upon by third parties or we may be unable to maintain, renew or enter into new licenses on commercially reasonable terms. Any misappropriation of our technology or development of competitive technologies could harm our business and could diminish or cause us to lose the competitive advantages associated with our proprietary technology, and could subject us to substantial costs in protecting and enforcing our intellectual property rights and/or temporarily or permanently disrupt our sales and marketing of the affected products or services. The laws of some countries in which our products are licensed do not protect our intellectual property rights to the same extent as the laws of the United States. Moreover, in some non-U.S. countries, laws affecting intellectual property rights are uncertain in their applications,application, which can affect the scope of enforceability of our intellectual property rights.

Third-party claims that we infringe the intellectual property rights of others may be costly to defend or settle and could damage our business.

        We cannot be certain that our software and services do not infringe issued patents, copyrights, trademarks or other intellectual property rights of third parties. Litigation regarding intellectual property rights is common in the software industry, and we may be subject to legal proceedings and claims from time to time, including claims of alleged infringement of intellectual property rights of third parties by us or our licensees concerning their use of our software products and integration technologies and services. Although we believe that our intellectual property rights are sufficient to allow us to market our software without incurring liability to third parties, thirdThird parties may bring claims of infringement against us. Because our software is integrated with our customers' networks and business processes, as well as other software applications, third parties may bring claims of infringement against us, as well as our customers and other software suppliers, if the cause of the alleged infringement cannot easily be determined.

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        Claims of alleged infringement may have a material adverse effect on our business and may discourage potential customers from doing business with us on acceptable terms, if at all. Defending against claims of infringement may be time-consuming and may result in substantial costs and diversion of resources, including our management's attention to our business. Furthermore, a party making an infringement claim could secure a judgment that requires us to pay substantial damages. A judgment could also include an injunction or other court order that could prevent us from selling our software or require that we re-engineer some or all of our products. Claims of intellectual property infringement also might require us to enter costly royalty or license agreements. We may be unable to obtain royalty or license agreements on terms acceptable to us or at all. Our business, operating results and financial condition could be harmed significantly if any of these events occurred, and the price of our common stock could be adversely affected. Furthermore, former employers of our current and future employees may assert that our employees have improperly disclosed confidential or proprietary information to us. In addition, we have agreed, and may agree in the future, to indemnify certain of our customers against claims that our software infringes upon the intellectual property rights of others. Although we carry general liability insurance, our current insurance coverage may not apply to, and likely would not protect us from, liability that may be imposed under any of the types of claims described above.

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If we are not successful in attracting, integrating and retaining highly qualified personnel, we may not be able to successfully implement our business strategy.

        Our ability to establish and maintain a position of technology leadership in the highly competitive software market depends in large part upon our ability to attract, integrate and retain highly qualified managerial, sales, technical and accounting personnel. Competition for qualified personnel in the software industry is intense. We have from time to time in the past experienced, and we expect to continue to experience in the future, difficulty in hiring and retaining highly skilled employees with appropriate qualifications. Our future success will depend in large part on our ability to attract, integrate and retain a sufficient number of highly qualified personnel, and there can be no assurance that we will be able to do so.

Our ability to raise capital in the future may be limited, and our failure to raise capital when needed could prevent us from executing our business plan.

        We expect that our current cash and cash equivalents and cash flows from operations will be sufficient to meet our anticipated cash needs for at least the next twelve months. We may need to obtain additional financing thereafter or earlier, however, if our current plans and projections prove to be inaccurate or our expected cash flows prove to be insufficient to fund our operations because of lower-than-expected revenue, fewer sales of installment receivable contracts, unanticipated expenses or other unforeseen difficulties.

        Our ability to obtain additional financing will depend on a number of factors, including market conditions, our operating performance, the quality of our receivables, and the availability of capital in the credit markets. These factors may make the timing, amount, terms and conditions of any financing unattractive. If adequate funds are not available, or are not available on acceptable terms, we may have to forego strategic acquisitions or investments, reduce or defer our development activities or delay our introduction of new products and services.

        Any additional capital raised through the sale of equity or convertible debt securities may dilute the existing stockholder percentage ownership of our common stock. Furthermore, any new securities we issue may have rights, preferences and privileges superior to our common stock. Capital raised through debt financings may require us to make periodic interest and principal payments and may impose potentially restrictive covenants on the conduct of our business.

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Risks Related to Our Common Stock

Our stock price may be adversely affected as more shares of our common stock become available for resale upon, or following, this offering.

        There may be negative pressure on our stock price as more shares of our common stock become available for resale as a consequence of this offering.

        In addition, other shares of our common stock held by the selling stockholders and not included in this offering will be eligible for resale in the public market, subject to volume limitations pursuant to Rule 144 under the Securities Act, although each of the selling stockholders has agreed to certain restrictions on transfers of our common stock during the 90-day period following the date of this prospectus except with the prior written consent of J.P. Morgan Securities Inc.LLC and Deutsche Bank Securities Inc. We previously granted to the selling stockholders rights to require that we register up to all of those shares under the Securities Act, although the selling stockholders will not be able to request a registration in connection with an additional underwritten public offering for a period of 18 months following completion of this offering. Sales by the selling stockholders, or other holders of a large number of our shares, of substantial amounts of our common stock in the public market after the completion of this offering, or the perception that those sales could occur, could adversely affect the

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market price of our common stock and could materially impair our future ability to raise capital through offerings of our common stock. Further, if a large number of shares of our common stock are sold in the public market after they become eligible for sale as a result of this offering, these sales could reduce the trading price of our common stock.

Following completion of this offering, the selling stockholders will continue to own a substantial portion of our capital stock and may have significant influence over our affairs.

        Upon completion of this offering, the selling stockholders collectively will own 14,512,336 shares of common stock, or 15.7%15.6% of our outstanding common stock, based upon shares outstanding as of July 2,August 16, 2010, assuming no exercise of the underwriters' overallotment option. In addition, two of our seven current directors previously were elected by the selling stockholders in their prior capacities as holders of shares of Series D-1 convertible preferred stock. As a result, the selling stockholders may exercise significant influence over corporate actions requiring stockholder approval, irrespective of how our other stockholders may vote, including:

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any amendment of our charter or bylaws;



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the approval of some mergers and other significant corporate transactions, including a sale of substantially all of our assets; or



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the defeat of any non-negotiated takeover attempt that might otherwise benefit the other stockholders.

Our common stock may experience substantial price and volume fluctuations.

        The equity markets have from time to time experienced extreme price and volume fluctuations, particularly in the high technology sector, and those fluctuations often have been unrelated to the operating performance of particular companies. In addition, factors such our new aspenONE licensing model, our financial performance, announcements of technological innovations or new products by us or our competitors, and market conditions in the computer software or hardware industries, may have a significant impact on the market price of our common stock.

        In the past, following periods of volatility in the market price of a public company's securities, securities class action litigation has often been instituted against that company. This type of litigation

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against us could result in substantial liability and costs and divert management's attention and resources.

Our corporate documents and provisions of Delaware law may prevent a change in control or management that stockholders may consider desirable.

        Section 203 of the Delaware General Corporation Law, our charter and our by-laws contain provisions that might enable our management to resist a takeover of our company. These provisions include:

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limitations on the removal of directors;



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a classified board of directors, so that not all members of the board are elected at one time;



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advance notice requirements for stockholder proposals and nominations;



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the inability of stockholders to act by written consent or to call special meetings;



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the ability of the board to make, alter or repeal our by-laws; and



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the ability of the board to designate the terms of and issue new series of preferred stock without stockholder approval.

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        These provisions could:

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have the effect of delaying, deferring or preventing a change in control of our company or a change in our management that stockholders may consider favorable or beneficial;



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discourage proxy contests and make it more difficult for stockholders to elect directors and take other corporate actions; and



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limit the price that investors might be willing to pay in the future for shares of our common stock.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS AND INDUSTRY DATA

        This prospectus contains forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act. Forward-looking statements relate to future events or our future financial performance. We generally identify forward-looking statements by terminology such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "potential," "should," "target," or the negative of these terms or other similar words. These statements are only predictions. The outcome of the events described in these forward-looking statements is subject to known and unknown risks, uncertainties and other factors that may cause our, our customers' or our industry's actual results, levels of activity, performance or achievements expressed or implied by these forward-looking statements, to differ. "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations" and "Business," as well as other sections in this prospectus, discuss some of the factors that could contribute to these differences. The forward-looking statements made in this prospectus relate only to events as of the date on which the statements are made. We undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which the statement is made or to reflect the occurrence of unanticipated events. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.

        This prospectus also contains estimates and other information concerning our industry, including market size and growth rates, that are based on industry publications, surveys and forecasts, including those generated by ARC Advisory Group. This information involves a number of assumptions and limitations, and you are cautioned not to give undue weight to these estimates. Although we believe the information in these industry publications, surveys and forecasts is reliable, we have not independently verified the accuracy or completeness of the information. The industry in which we operate is subject to a high degree of uncertainty and risk due to variety of factors, including those described in "Risk Factors."

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USE OF PROCEEDS

        The selling stockholders are offering all of the shares of common stock offered by this prospectus and will receive all of the proceeds from this offering. For information about the selling stockholders, see "Principal and Selling Stockholders—Selling Stockholders."

        We will not receive any of the proceeds from this offering. We are obligated to pay all expenses we incur in connection with this offering, including all registration and filing fees, printing expenses, fees and expenses of our counsel and of one separate counsel designated by the selling stockholders, and state Blue Sky fees and expenses. The selling stockholders will pay other expenses they incur in connection with this offering, including all underwriting discounts and commissions.

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MARKET PRICE OF COMMON STOCK

        Our common stock is traded on The NASDAQ Global Select Market under the symbol "AZPN." Our common stock was traded on The NASDAQ Global Select Market (and its predecessors, the NASDAQ National Market and NASDAQ Global Market) from our initial public offering in 1994 through February 18, 2008, and then was quoted on the over the counter Pink OTC Markets under the symbol "AZPN.PK" until being relisted on The NASDAQ Global Select Market on February 10, 2010. The following table sets forth, for the periods indicated, the high and low sales prices per share of our common stock as reported by The NASDAQ Global Select Market or the Pink OTC Markets, as applicable:

        On July 29,September 14, 2010, the last reported sale price for our common stock on The NASDAQ Global Select Market was $10.92$10.37 per share. On July 15,August 16, 2010, there were 785784 holders of record of our common stock. The number of record holders does not include persons who held our common stock in nominee or "street name" accounts through brokers.

DIVIDEND POLICY

        We have never declared or paid cash dividends on our common stock. We currently intend to retain all earnings, if any, to finance the development and growth of our business and do not anticipate paying cash dividends on our common stock in the foreseeable future. Any future determination relating to our dividend policy will be made at the discretion of the board of directors and will depend on a number of factors, including our future earnings, capital requirements, financial condition and future prospects and such other factors as the board may deem relevant. In addition, under the terms of our credit facility, we may not declare or pay any cash dividends on our common stock without the prior approval of the lender, Silicon Valley Bank.

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CAPITALIZATION

        The following table describes our current portion of secured borrowing and our capitalization as of March 31,June 30, 2010. You should read this table together with the other financial information contained in this prospectus, including "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the consolidated financial statements and related notes beginning at page F-1.

        The number of shares of common stock issued and outstanding as of March 31,June 30, 2010 excludes:

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630,640 shares issuable upon the exercise of warrants outstanding and exercisable as of March 31,June 30, 2010, at an exercise price of $3.33 per share;



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5,410,2625,266,354 shares issuable upon the exercise of options outstanding and vested as of March 31,June 30, 2010, at a weighted average exercise price of $7.12$7.11 per share;



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200,599129,516 shares issuable upon the exercise of options outstanding but not vested as of March 31,June 30, 2010, at a weighted average exercise price of $10.31$10.24 per share;



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1,706,3541,512,263 shares issuable upon the vesting of restricted stock units outstanding as of March 31,June 30, 2010, without payment of an exercise price; and



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1,278,3658,348,803 shares authorized and available as of March 31,June 30, 2010, for future issuance under our equity compensation plans.

A total of 7,000,000 additional shares were authorized and became available for future issuance as of April 15, 2010 under a newly adopted equity compensation plan.

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SELECTED CONSOLIDATED FINANCIAL DATA

        The data set forth below should be read in conjunction with our consolidated financial statements, "Management's Discussion and Analysis of Financial Condition and Results of Operations," and the other financial information presented in this prospectus. The consolidated statementsstatement of operations data for the years ended June 30, 20082010, 2009 and 20092008 and the consolidated balance sheet data as of June 30, 20082010 and 2009 are derived from consolidated financial statements included in this prospectus in reliance on the report of KPMG LLP. The consolidated statements of operations data for the yearyears ended June 30, 2007 are derived from consolidated financial statements included in this prospectus in reliance on the report of Deloitte & Touche LLP. The consolidated statements of operations data for the years ended June 30, 2005 and 2006 and the consolidated balance sheet data as of June 30, 2005,2008, 2007 and 2006 and 2007 are derived from audited consolidated financial statements not included in this prospectus. The consolidated statements of operations data for the nine months ended March 31, 2009 and 2010 and the consolidated balance sheet data as of March 31, 2010 are derived from unaudited consolidated financial statements included in this prospectus that, in the opinion of management, have been prepared on the same basis as the audited consolidated financial statements and reflect all adjustments, consisting only of normal recurring adjustments, necessary for the fair presentation of the information for the periods presented. Historical results are not necessarily indicative of operating results to be expected in the future. Basic and diluted income (loss) per share and weighted average shares outstanding have been computed as described in note 3(i)2(i) to the consolidated financial statements beginning on page F-1.

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        Following the introduction of our new aspenONE licensing model, management focuses on certain metrics, including the key metrics set forth below, to assist in operating and assessing our business. We believe these metrics are useful to investors in evaluating our operating performance following the introduction of our new licensing model. None of these metrics should be considered as an alternative to any measure of financial performance calculated in accordance with U.S. generally accepted accounting principles or GAAP, including net cash provided by operating activities, which is the GAAP financial measure most directly comparable to free cash flow. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Key Business Metrics."

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For these purposes:

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Total term contract value,or TCV, is an estimate of the renewal value, as of a specific date, of our active portfolio of term license agreements. TCV is calculated by multiplying the terminal annual payment for each active term license agreement by the original length of the existing license term, and then aggregating this amount for all active term license agreements. TCV includes the value of SMS for license agreements under our new aspenONE licensing model, in which SMS is committed for the entire license term. TCV does not include any amounts for perpetual licenses, professional services, training or standalone renewal SMS.



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Bookings represent the amount of contractually committed subscription and software fees, including any bundled software maintenance and support or SMS. Bookings do not include (a) the amount of fees for professional services, training and standalone renewal SMS or (b) the amount of subscription and software fees remaining under existing license agreements that are replaced prior to the scheduled expiration date.



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Billings backlog represents the aggregate value of uninvoiced bookings from prior and current periods. Billings backlog is not reflected on our consolidated balance sheets.

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MANAGEMENT'S DISCUSSION AND ANALYSIS OF
FINANCIAL CONDITION AND RESULTS OF OPERATIONS

        You should read the following discussion in conjunction with our consolidated financial statements and related notes beginning on page F-1. In addition to historical information, this discussion contains forward-looking statements that involve risks and uncertainties. You should read "Risk Factors" for a discussion of important factors that could cause our actual results to differ materially from our expectations.

        Our fiscal year ends on June 30, and references to a specific fiscal year are to the twelve months ended June 30 of that year. For example, "fiscal 2010" refers to the year ended June 30, 2010.

Business Overview

        We are a leading global provider of mission-critical process optimization software solutions, which are designed to manage and optimize plant and process design, operational performance, and supply chain planning. Our aspenONE software and related services have been developed specifically for companies in the process industries. Customers use our solutions to improve their competitiveness and profitability by increasing throughput and productivity, reducing operating costs, enhancing capital efficiency, and decreasing working capital requirements.

        We have more than 1,500 customers globally. Our customers include manufacturers in process industries such as energy, chemicals, pharmaceuticals, consumer packaged goods, power, metals and mining, pulp and paper, and biofuels, as well as engineering and construction firms that help design process manufacturing plants. As of June 30, 2010, our installed base included 19 of the 20 largest petroleum companies, all of the 20 largest chemical companies, and 15 of the 20 largest pharmaceutical companies. Customers outside the United States accounted for a majority of our total revenue in each of fiscal 2007,2010, 2009 and 2008, and 2009, and no single customer represented 10% or more of our total revenue in fiscal 2007, 20082010, 2009 or 2009.

        In July 2009 we began offering our new aspenONE licensing model under which we recognize license revenue over the term of a license contract. Our new licensing model provides customers with access to all of the applications within the aspenONE suite or suites they license, and it includes software maintenance and support, or SMS, for the term of the license and the right to unspecified future software products and upgrades that may be introduced into the licensed suite during the term of the arrangement. Prior to July 2009 we primarily recognized license revenue "upfront," upon shipment of software, on a net present value basis in the period in which a license contract was signed, not over the license period. Generally SMS was bundled for the first year of a license contract, recognized ratably and renewed annually at the customer's discretion. Under both our earlier upfront model and our new licensing model, license contracts typically have terms of five to six years.

        Since introducing our new aspenONE licensing model, we have experienced favorable customer adoption rates that are driving our transition to a subscription revenue model. As a result of this transition, our revenue for fiscal 2010 was significantly less than in the preceding fiscal years. We expect that, as customers renew under our new licensing model, our revenue will increase gradually over the next several fiscal years. Our new licensing model has not changed the method or timing of our customer billing and cash collections.2008.

Transition to New aspenONE Licensing Model

        In July 2009, we announced that for the fiscal year commencing July 1, 2009, we would offer a new term licensing model for our software. Our new aspenONE licensing model provides customers with access to all products within the aspenONE suite or suites they license. As part of our new licensing model, customers receive, for no additional fee, SMS for the term of the license and the right to

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unspecified future software products and upgrades that may be introduced into the licensed suite during the term of the arrangement. Our new licensing model provides customers the ability to utilize any product within a licensed aspenONE suite through the use of tokens (exchangeable units of measurement), which they license in quantities they determine to be sufficient for their business needs. Our new licensing model provides customers with increased access to aspenONE products, and we believe this flexibility will lead to increased usage and revenue over time.

        Prior to fiscal 2010, we offered term or perpetual licenses to our customers with extended payment terms forspecific aspenONE products or specifically defined sets of aspenONE products, referredwhich we refer to as point products, based upon the customers' particular needs. We typicallyproducts. The majority of our license revenue was recognized under an "upfront revenue for these term license agreements upon shipment of the software, atmodel," in which the net present value of the aggregate license fees provided all other revenue recognition criteria were met. We refer to this revenue recognition approach as the "upfront revenue model." We also sold perpetual licenses, for which revenue also was recognized on an upfront basis. An increasing majorityas revenue upon shipment of our software licenses were term-based. License fees that did not qualify for upfront revenue recognition were either deferred until such timethe point products. We typically invoiced customers annually and recorded the net present value of uninvoiced payments as all revenue recognition criteria had been met or recognized over the license term.

        Under the upfront revenue model, we offered annually renewable post-contract SMS as a component of our arrangements. Generally SMS was provided for the firstinstallments receivable. Customers typically received one year of theSMS bundled with their license agreementagreements and renewed annually at the customer's discretion.then could elect to renew SMS annually. Revenue from SMS was recognized ratably over the term ofperiod during which the SMS agreement. For the majority ofwas delivered.

        On July 1, 2009, we began offering our existingaspenONE software arrangements under the upfront revenue model, customers renewed their support contracts when eligible to do so.

        Arrangements under oura new aspenONEterm licensing model, do not qualify for upfront revenue recognition because customers haveunder which a customer can access all products within a licensed suite (aspenONE Engineering or aspenONE Manufacturing and Supply Chain). During the rightlicense term, a customer is entitled to future unspecified products.receive SMS as well as any software products and upgrades introduced into the licensed suite. Revenue under our new licensing model is recognized over the term of thea license agreement on a subscription basis, beginning whenbasis. We typically issue invoices annually, and we record each invoiced payment as deferred revenue and then recognize revenue from that payment over the first paymentapplicable period. We also continue to offer our customers the ability to license point products, which in July 2009, we began licensing with SMS bundled for the entire term. Revenue is due, which typically is 30 days after execution of the agreement.

        As a result of the changes to our business model, the majority of our license revenue is no longer recognized on an upfront basis, but instead is recognizedthese arrangements over the contract term, either on a subscription basis or as payments become due. Because we previously recognized a substantial majority ofUninvoiced payments are not recorded on our license revenue upon shipment of software, our revenue for fiscal 2010 was significantly lower than in the preceding years. We expect that, as customers renew under our new licensing model, our revenue will increase gradually over the next several fiscal years. Additionally, if a professional service arrangement is contracted in close proximity to a related license agreement that qualifies for recognition under our new aspenONE licensing model, the professional services revenue will be recognized over the contract term. Because there will not be a corresponding reduction in operating costs, we anticipate reporting significant operating and net losses for the next several fiscal years.consolidated balance sheet.

        Our new aspenONE licensing model has not changed the method or timing of our customer billing andor cash collections. We continue to invoice a customer over the contract term (generally on an annual basis), provided the customer does not elect to make payment in full at the outset of the arrangement. Consequently, we do not expect any material change to net cash provided by

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operating activities as a result of the changestransition to the way we license our products, assuming the introduction of our new licensing model does not negatively impact customer retention.

        Under the upfront revenue model, we record the net present valuemodel. The principal accounting implications of the uninvoiced payments remaining onchange in our licensing model are as follows:

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The majority of our license contracts as installments receivable. Underrevenue is no longer recognized on an upfront basis. As the result of the transition to our new aspenONE licensing model, our license revenue for fiscal 2010 was significantly less than the arrangement fees are not deemed to be fixed or determinable and as a result uninvoiced payments remaining on these new license contracts will not be recorded onlevel achieved in the balance sheet.preceding fiscal years. We expect that the transition toour license revenue will increase as customers renew their licensing arrangements under our new licensing modelmodel. We do not expect to recognize levels of revenue comparable to prior fiscal years unless and until a significant majority of our existing license agreements have been renewed under our new licensing model. Because the timing of our incurrence of operating costs has not changed, the lower levels of revenue expected over the next few years will cause theresult in significant operating and net losses.



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The amount of our installments receivable balance to declinewill decrease over time. Additionally, we expecttime, as license agreements executed under our upfront revenue model reach the end of their terms.



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The amount of our deferred revenue will increase over time, because the annualas installments for license transactions executed under our new licensing model will beare deferred and recognized on a subscription basis. We will not, however, realize a significant increase in deferred revenue until a




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significant substantial portion of the existing term contracts recognizedlicense agreements previously executed under our upfront revenue model has been renewed under our new licensing model.

        For additional information about the recognition of revenue under the upfront revenue model expire and are renewed under our new aspenONE licensing model.model, see "—Revenue." Because of the accounting implications of our new aspenONE licensing model, we believe that, for the next several years, a number of performance indicators based on U.S. generally accepted accounting principles, or GAAP, will be of limited value in assessing our performance, growth and financial condition. Accordingly, we are focusing on a number of other business metrics, including those described under "—Key Business Metrics."

Revenue

        We continue to offer term licenses for specifically defined sets of point products. In July 2009 we began licensing point products with SMS included forgenerate revenue primarily from the full license term. Revenue from these arrangements is recognized over the term of the contract as payments become due. The related SMS revenue is recognized over the term of the SMS agreement, beginning with the due date of the annual payment, and is reported in services and other revenue on our consolidated statements of operations. We expect that occasionally a customer will elect upfront payment terms, in which case all of the license revenue will be recognized upfront by applying the residual method of accounting.following sources:

        We generally do not intend to enter into new or renewal term contracts that will qualify for revenue recognition under the upfront revenue model, but we may elect to do so on a limited basis. The incremental revenue associated with amendments to existing term contracts that was recognized under the upfront revenue model will continue to be accounted for on an upfront basis, provided all other revenue recognition requirements have been met. Additionally, we will continue to offer perpetual license arrangements. We do not anticipate that either of these types of arrangements will generate a significant portion of our license revenue in the future.

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Operating Segments

        An overview of our three operating segments follows.

Software Licenseslicenses.

  We provide integrated process optimization software solutions designed specifically for the process industries. Our aspenONEWe license our software applications are organized into two suites: aspenONE Engineeringproducts on a term or perpetual basis, and aspenONE Manufacturing and Supply Chain. While a significant number of our customers have already migrated to our new aspenONE licensing model, we also offer our customers the ability to purchase applications as point products.

        Because feesextended payment options for our software can be substantial and the decision to purchase our software often involves members of our customers' senior management, the sales process for our solutions is frequently lengthy and can exceed one year. Accordingly, the timing of ourterm license bookings is difficult to predict. Additionally, because we derive a majority of our total revenue from companies in or serving the energy, chemicals and pharmaceutical industries, our future success depends upon the continued demand for process optimization software and services by companies in or serving those industries. The energy, chemicals and pharmaceutical industries are highly cyclical and highly reactive to the price of oil, as well as general economic conditions.

agreements that generally require annual payments.



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    Maintenance, Training and OtherSMS.

  Our maintenanceSMS business consists primarily of providing customer technical support and access to software fixes and upgrades. OurWe provide customer technical support services are provided throughout the world by our three global call centers as well as via email and through our support website. Our training business consists of a variety of training solutions ranging from standardized training, which can be delivered in a virtual environment or at a customer's location, to customized training sessions that can be tailored to fit customer needs.

        Revenue generated by our maintenance, training and other business is closely correlated to changes in our installed base of software licenses. For the majority of our existing software arrangements under the upfront revenue model, customers renewed their support contracts when eligible to do so.




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        We expect SMS revenue to decrease as we transition our business to a predominantly subscription-based model, because the revenue associated with SMS will be reported as subscription revenue. Further, we anticipate reduced SMS revenue due to the continued trend of customers electing to replace perpetual agreements with new term contracts. Moving customers to term-based contracts generally results in larger combined software and SMS revenue, although it results in lower SMS revenue. We expect the majority of our customers eventually will license our products under our new aspenONE licensing model, and accordingly the majority of revenue associated with SMS will be included in subscription revenue.

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Professional Servicesservices.

  We offer professional services that include implementing and integrating our software applications for customers that are seeking to integrate our technology with their existing systems in order to further improve their plant performance and gain better operational data.applications. Customers who use our professional services typically engage us to provide those services over periods of up to 24 months. We charge customers for professional services on a time-and-materials or fixed-price basis. Professional