<SEC-DOCUMENT>0000921895-19-001135-index.html : 20190419
<SEC-HEADER>0000921895-19-001135.hdr.sgml : 20190419
<ACCEPTANCE-DATETIME>20190419165136
ACCESSION NUMBER:		0000921895-19-001135
CONFORMED SUBMISSION TYPE:	SC 13D/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20190419
DATE AS OF CHANGE:		20190419

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PDF SOLUTIONS INC
		CENTRAL INDEX KEY:			0001120914
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING SERVICES [7371]
		IRS NUMBER:				251701361
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13D/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-77927
		FILM NUMBER:		19758205

	BUSINESS ADDRESS:	
		STREET 1:		2858 DE LA CRUZ BOULEVARD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95050
		BUSINESS PHONE:		4082807900

	MAIL ADDRESS:	
		STREET 1:		2858 DE LA CRUZ BOULEVARD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95050

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			VIEX Capital Advisors, LLC
		CENTRAL INDEX KEY:			0001619125
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13D/A

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Vertex Capital Advisors, LLC
		DATE OF NAME CHANGE:	20140910
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13D/A
<SEQUENCE>1
<FILENAME>sc13da210114027_04192019.htm
<DESCRIPTION>AMENDMENT NO. 2 TO THE SCHEDULE 13D
<TEXT>
Document 1 - file: sc13da210114027_04192019.htm

</DOCUMENT>
</SEC-DOCUMENT>