SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* HARTGRING CORNELIS (Last) (First) (Middle) 333 W. SAN CARLOS ST. SUITE 1000 (Street) SAN JOSE CA 95110 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol PDF SOLUTIONS INC [ PDFS ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) Vice President, CSS
	3. Date of Earliest Transaction (Month/Day/Year) 02/16/2017
	4. If Amendment, Date of 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

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	02/16/2017		M		10,855	A	(1)	47,441(2)	D
Common Stock	02/16/2017		S		17,952	D	(3)	29,489	D
Common Stock	02/17/2017		S		981	D	(4)	28,508	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 (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 Securities Underlying Derivative Security (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: 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
Stock Options (Right to Buy)	$6.21	02/16/2017		M			1,688	(5)	05/26/2021	Common Stock	1,688	$6.21	0	D
Stock Options (Right to Buy)	$8.79	02/16/2017		M			2,500	(6)	05/22/2022	Common Stock	2,500	$8.79	0	D
Stock Options (Right to Buy)	$8.79	02/16/2017		M			6,667	(7)	05/22/2022	Common Stock	6,667	$8.79	0	D

Explanation of Responses:

1. Includes exercise of fully vested stock options grants awarded to the Reporting person on May 22, 2011 and on May 22, 2012

2. Includes 1,561 shares of common stock that were purchased on January 31, 2017 under the PDF Employee Stock Purchase Plan

3. Average weighted sale price for shares disposed of in the reported transaction. The shares were sold in multiple brokers' transactions at various market prices per share ranging from $22.00 to $22.52.

4. Average weighted sale price for shares disposed of in the reported transaction. The shares were sold in multiple brokers' transactions at various market prices per share ranging from $22.134 to $22.1596.

5. Earliest vesting date of the stock options granted on May, 27, 2011 was June 27, 2011 with 1/48th of the total shares vesting monthly until fully vested on June 27, 2014.

6. 1/4th of the total number of shares subject to option vested on May 22, 2012 and 1/4th of the total shares vested each anniversary of the grant date, fully vested on May 22, 2015.

7. Earliest vesting date of the total stock options granted on May 22, 2012 was June 22, 2012 1/48th of the total shares vesting monthly until fully vested on June 22, 2016.

	/s/ Gregory Walker, Attorney-in-Fact for Cornelis Hartgring	02/21/2017
	** Signature of Reporting Person	Date
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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