FORM 4 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 OF SECURITIES 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 (Month/Day/Year) 02/01/2018 (Street) CAMBRIDGE, MA 02142 4. If Amendment, Date Original Filed(Month/Day/Year) 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 02/01/2018   M   2,186 (1) A $ 0 3,372 D   Common Stock 02/01/2018   F   694 D $ 50.85 2,678 D   Common Stock 02/01/2018   M   3,500 A $ 0 6,178 D   Common Stock 02/01/2018   F   2,382 (2) D $ 50.6 3,796 D   Common Stock 02/01/2018   S   1,118 (3) D $ 51.52 (4) 2,678 D   Common Stock 02/01/2018   S   2,678 (3) D $ 51.52 (4) 0 (5) D

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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 (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

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 (Month/Day/Year)

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 (6)

$ 0

02/01/2018

M

2,186 (1)

08/01/2017

(7)

Common Stock

43,732

$ 0

28,426

D

Stock Options

$ 27.74

02/01/2018

M

3,500

08/01/2017(7)

08/01/2026

Common Stock

211,516

$ 0

187,516

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
STILLWELL KENNETH C/O PEGASYSTEMS INC ONE ROGERS STREET CAMBRIDGE, MA 02142			CFO, SVP

Signatures

/s/ Janet Mesrobian, Esq., Attorney-In-Fact for Kenneth Stillwell		02/05/2018
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Represents 5% vesting on February 1, 2018. The original grant was 43,732 restricted stock units, with 20% vesting on August 1, 2018, and the remaining 80% vesting in equal quarterly installments over the remaining 4 years.
(2)	Represents the exercise price of the Stock Options referenced in Table II and Mr. Stilwell's tax liability, which were paid by way of withholding by the Company of shares of equal value
(3)	Sold pursuant to a pre-arranged stock trading plan under rule 10b5-1 of the Securities Exchange Act of 1934, as amended.
(4)	Represents the weighted average of the sale prices on February 1, 2018, ranging from $50.65 to $51.80.
(5)	Does not include shares of common stock subject to unvested restricted stock units and option awards.
(6)	Each restricted stock unit represents the right to receive, following vesting, one share of Pegasystems Inc.'s common stock.
(7)	Once vested, the shares of common stock are not subject to expiration.

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