Sec Form 4/A Filing - STILLWELL KENNETH @ PEGASYSTEMS INC - 2019-05-01

FORM 4/A Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person STILLWELL KENNETH 2. Issuer Name and Ticker or Trading Symbol PEGASYSTEMS INC [ PEGA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) CFO, SVP (Last) (First) (Middle) C/O PEGASYSTEMS INC, ONE ROGERS STREET 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2019 (Street) CAMBRIDGE, MA02142 4. If Amendment, Date Original Filed (MM/DD/YY) 05/03/2019 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/01/2019 M 2,186 ( 1 ) A $ 0 8,355 D Common Stock 05/01/2019 F 828 D $ 75.01 7,527 ( 2 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Restricted Stock Units ( 3 ) $ 0 05/01/2019 M 2,186 ( 1 ) 08/01/2017 ( 4 ) Common Stock 2,186 $ 0 19,680 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other STILLWELL KENNETH C/O PEGASYSTEMS INC ONE ROGERS STREET CAMBRIDGE, MA02142 CFO, SVP Signatures /s/ Janet Mesrobian, Esq., Attorney-in-Fact for Kenneth Stillwell 06/05/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents 5% vesting on May 1, 2019. The original grant was 43,732 restricted stock units, with 20% vesting on August 1, 2017, and the remaining 80% vesting in equal quarterly installments over the remaining four years. ( 2 )The Form 4 filed on May 3, 2019 is being amended to correct that in addition to the amount sold pursuant to Kenneth Stillwell's 10b5-1 plan, there was a restricted stock unit vesting on May 1, 2019 of 2,186 shares, with 828 being withheld to cover Mr. Stillwell's tax liability and 1,358 shares being disbursed. Forms filed after May 3, 2019 understated Mr. Stillwell's ownership by 1,358 shares. ( 3 )Each restricted stock unit represents the right to receive, following vesting, one share of the issuer's common stock. ( 4 )Once vested, the shares of common stock are not subject to expiration.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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