Exhibit 99.1

Pegasystems Announces Financial Results for First Quarter of 2016

Strong Revenue Growth Drives Higher Profitability

CAMBRIDGE, Mass. – May 5, 2016 – Pegasystems Inc. (NASDAQ: PEGA), the software company empowering the world’s leading enterprises with strategic business applications, today announced results for its first quarter ended March 31, 2016.

“We are pleased with the start to 2016,” said Alan Trefler, Founder and CEO of Pegasystems. “We had strong Q1 revenue, which contributed to a dramatic increase in this quarter’s EPS. We will be focusing our efforts in coming quarters to balance revenue with an emphasis on increasing backlog and are encouraged that we have the pipeline and activity to achieve this. We continue to make progress in positioning Pega as a leader in strategic applications to help enterprises better serve their customers. We’re delighted with the recognition we are receiving from the industry and the tremendous value our clients are getting from our software.”

SELECTED GAAP & NON-GAAP RESULTS (1)

Cash: Total cash, cash equivalents, and marketable securities at March 31, 2016 was $193.9 million, a decrease of 11% from 2015 year-end. The reduction was primarily due to the payment of annual bonuses and $10.1 million of marketable securities sold in the quarter, which did not settle until April 2016 and are reflected in other current assets as of March 31, 2016.

Cash generated from operations for the quarter was $8.6 million.

License and Cloud Backlog: The Company computes license and cloud backlog by adding billed deferred license and cloud revenue and off-balance sheet license and cloud commitments, which is business that is contracted, not billed, and not recorded on the Company’s balance sheet.

License and Cloud Backlog (1)

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OpenSpan Acquisition Impact

In April 2016, the Company acquired OpenSpan, Inc. (“OpenSpan”), a privately held software provider of robotic process automation and workforce analytics software. The Company expects the acquisition to be accretive starting in 2017.

As a result of the acquisition, the Company is updating its previous guidance for the full year 2016 as follows: The Company now expects GAAP and non-GAAP revenue to be approximately $800 million. GAAP diluted EPS is expected to be approximately $0.44 per share, while non-GAAP diluted EPS is expected to be consistent with the previously announced guidance of approximately $0.95 per share.

Quarterly Conference Call

Pegasystems will host a conference call and audio-only Webcast associated with this announcement at 5:00 p.m. EDT today. A live audio Webcast of the conference call, together with detailed financial information, can be accessed through the Company’s Website at www.pega.com/about/investors. Dial-in information is as follows: 1-877-407-3982 (domestic) or 1-201-493-6780 (international). To listen to the Webcast, log onto www.pega.com at least five minutes prior to the event’s broadcast and click on the Webcast icon in the Investors section. A replay of the call will also be available on www.pega.com by clicking the Earnings Calls link in the Investors section.

Discussion of Non-GAAP Financial Measures:

To supplement financial results presented in accordance with Generally Accepted Accounting Principles in the U.S. (“GAAP”), the Company provides non-GAAP measures, including in this release. Pegasystems’ management utilizes a number of different financial measures, both GAAP and non-GAAP, in analyzing and assessing the overall performance of the business, for making operating decisions, and for forecasting and planning for future periods. The Company’s annual financial plan is prepared both on a GAAP and non-GAAP basis, and both are approved by our board of directors. In addition and as a consequence of the importance of these measures in managing the business, the Company uses non-GAAP measures and financial performance results in the evaluation process to establish management’s compensation.

The non-GAAP measures exclude stock-based compensation expense, amortization of acquired intangibles, acquisition-related and restructuring expenses, and certain other adjustments. The Company believes that these non-GAAP measures are helpful in understanding its past financial performance and its anticipated future results. These non-GAAP financial measures are not meant to be considered in isolation or as a substitute for comparable GAAP measures and should be read only in conjunction with the Company’s consolidated financial statements prepared in accordance with GAAP. A reconciliation of the Company’s GAAP to non-GAAP measures is included in the financial schedules at the end of this release.

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Forward-Looking Statements

“Safe harbor” statement under the Private Securities Litigation Reform Act of 1995: Certain statements contained in this press release may be construed as “forward-looking statements” as defined in the Private Securities Litigation Reform Act of 1995, including our updated guidance regarding 2016 GAAP and non-GAAP revenue and diluted earnings per share. The words “expect,” “anticipate,” “intend,” “plan,” “believe,” “could,” “estimate,” “may,” “target,” “strategy,” “is intended to,” “project,” “guidance”, or variations of such words and similar expressions, among others, identify forward-looking statements, which speak only as of the date the statement was made. These statements are based on current expectations and assumptions and involve various risks and uncertainties, which could cause the Company’s actual results to differ from those expressed in such forward-looking statements. These risks and uncertainties include, among others, variation in demand for our products and services and the difficulty in predicting the completion of product acceptance and other factors affecting the timing of our license revenue recognition; the ongoing consolidation in the financial services, insurance, healthcare, and communications markets; reliance on third party relationships; the potential loss of vendor specific objective evidence for our time and materials professional services arrangements; the inherent risks associated with international operations and the continued weakness in international economies; foreign currency exchange rates; the financial impact of the Company’s past acquisitions, including the OpenSpan acquisition, and any future acquisitions; the potential legal and financial liabilities and reputation damage due to cyber-attacks and security breaches; and management of the Company’s growth. Further information regarding these and other factors which could cause the Company’s actual results to differ materially from any forward-looking statements contained in this press release is contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 and other recent filings with the Securities and Exchange Commission. These documents are available on the Company’s website at http://www.pega.com/about/investors. The forward-looking statements contained in this press release represent the Company’s views as of May 5, 2016. Investors are cautioned not to place undue reliance on such forward-looking statements and there are no assurances that the matters contained in such statements will be achieved. Although subsequent events may cause the Company’s view to change, except as required by applicable law, the Company does not undertake and specifically disclaims any obligation to publicly update or revise these forward-looking statements whether as the result of new information, future events or otherwise. The statements should therefore not be relied upon as representing the Company’s view as of any date subsequent to May 5, 2016.

About Pegasystems

Pegasystems (NASDAQ: PEGA) develops strategic applications for marketing, sales, service, and operations. Pega’s applications streamline critical business operations, connect enterprises to their customers seamlessly in real-time across channels, and adapt to meet rapidly changing requirements. Pega’s Global 3000 customers include many of the world’s most sophisticated and successful enterprises. Pega’s applications, available in the cloud or on-premises, are built on its unified Pega 7 platform, which uses visual tools to easily extend and change applications to meet clients’ strategic business needs. Pega’s clients report that Pega gives them the fastest time to value, extremely rapid deployment, efficient re-use and global scale. For more information, please visit us at www.pega.com.

Press Contacts:

Lisa Pintchman

Pegasystems Inc.

lisa.pintchman@pega.com

(617) 866-6022

Twitter: @pega

Investor Contact:

Sheila Ennis

ICR for Pegasystems

PegaInvestorRelations@pega.com

617-866-6077

All trademarks are the property of their respective owners.

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Pegasystems Inc.

Unaudited Condensed Consolidated Statements of Operations

($ in thousands, except per share amounts)

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PEGASYSTEMS INC.

RECONCILIATION OF SELECTED GAAP MEASURES TO NON-GAAP MEASURES (1)

($ in thousands, except per share amounts)

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PEGASYSTEMS INC.

FOOTNOTES FOR RECONCILIATON OF

SELECTED GAAP MEASURES TO NON-GAAP MEASURES

Amortization of intangible assets: We have excluded the amortization expense of intangible assets from our non-GAAP operating expenses and net earnings measures. Amortization of intangible assets is inconsistent in amount and frequency and is significantly affected by the timing and size of our acquisitions. Investors should note that the use of intangible assets contributed to our revenues earned during the periods presented and will contribute to our future period revenues as well. Amortization of intangible assets will recur in future periods.

Stock-based compensation expense: We have excluded stock-based compensation expense from our non-GAAP operating expenses and net earnings measures. Although stock-based compensation is a key incentive offered to our employees, and we believe such compensation contributed to the revenues earned during the periods presented and will contribute to the generation of future period revenues, we continue to evaluate our business performance excluding stock-based compensation expense.

Acquisition-related and restructuring expenses: We have excluded the effect of acquisition-related and restructuring expenses from our non-GAAP operating expenses and net earnings measures. We incurred direct and incremental expenses associated primarily with the OpenSpan acquisition. These acquisition-related expenses were primarily professional fees to affect the acquisition. We have also incurred restructuring expenses for one-time employee termination benefits related to the closure of one of our domestic offices, which we generally would not have otherwise incurred in the periods presented as a part of our continuing operations. We believe it is useful for investors to understand the effects of these items on our total operating expenses.

Other adjustments: We reached an agreement with the former shareholders of Antenna Software, Inc., which we acquired in October 2013 (“Antenna”), to release a portion of the funds held in escrow as security for their indemnification obligations to us in settlement of the outstanding indemnification claims. The settlement resulted in a benefit to cost of revenue and operating expenses in the first quarter of 2015. In addition, we favorably settled indirect tax liabilities related to the Antenna acquisition, which resulted in a benefit to operating expenses in the first quarter of 2015. We believe the benefits associated with these items are not representative of our ongoing business, and we have excluded the effects of these items from our non-GAAP operating results and net earnings measures.

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The difference between our GAAP and non-GAAP effective tax rates in first quarter of 2016 primarily relates to the impact of unfavorable foreign stock compensation adjustments on our GAAP effective tax rate, partially offset by higher non-GAAP income subjected to tax in higher tax jurisdictions. The difference between our GAAP and non-GAAP effective tax rates for the first quarter of 2015 primarily relates to the impact of higher non-GAAP income subjected to tax in lower tax rate jurisdictions.

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Pegasystems Inc.

Unaudited Condensed Consolidated Balance Sheets

(in thousands)

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Pegasystems Inc.

Unaudited Condensed Consolidated Statements of Cash Flows

(in thousands)

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Pegasystems Inc.

Historical License and Cloud Backlog

(in thousands)

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FY 2016 Reconciliation of Forward-Looking Guidance

($ in thousands, except per share amounts)

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