<SEC-DOCUMENT>0001437749-14-009379.txt : 20140516
<SEC-HEADER>0001437749-14-009379.hdr.sgml : 20140516
<ACCEPTANCE-DATETIME>20140516130517
ACCESSION NUMBER:		0001437749-14-009379
CONFORMED SUBMISSION TYPE:	DEFA14A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20140516
DATE AS OF CHANGE:		20140516
EFFECTIVENESS DATE:		20140516

FILER:

	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:		DEFA14A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-31311
		FILM NUMBER:		14850663

	BUSINESS ADDRESS:	
		STREET 1:		333 WEST SAN CARLOS STREET
		STREET 2:		SUITE 700
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
		BUSINESS PHONE:		4082807900

	MAIL ADDRESS:	
		STREET 1:		333 WEST SAN JOSE STREET
		STREET 2:		SUITE 700
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
</SEC-HEADER>
<DOCUMENT>
<TYPE>DEFA14A
<SEQUENCE>1
<FILENAME>pdfs20140513_defa14a.htm
<DESCRIPTION>FORM DEFA14A
<TEXT>
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<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA1><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B></B></FONT>&nbsp;</P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>UNITED STATES</B></FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA3><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>SECURITIES AND EXCHANGE COMMISSION</B></FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA5><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>Washington, D.C. 20549</B></FONT></P>
<P style="MARGIN-TOP: 0pt; MARGIN-BOTTOM: 0pt" id=PARA6><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA8><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>SCHEDULE 14A</B></FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA9><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA10><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Proxy Statement Pursuant to Section 14(A) of the</FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA11><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Securities Exchange Act of 1934 (Amendment No.___)</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA12><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA13><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Filed by the Registrant&nbsp;&nbsp;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9745;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA14><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA15><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Filed by a Party other than the Registrant&nbsp;&nbsp;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA16><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA17><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Check the appropriate box:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA18><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA19><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;&nbsp;Preliminary Proxy Statement</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA20><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>&nbsp;&nbsp;Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))</B></FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA21><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp; Definitive Proxy Statement</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA22><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9745;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;&nbsp;Definitive Additional Materials</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA23><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;&nbsp;Soliciting Material Under Rule &#167; 240.14a-12</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA24><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA25><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>PDF SOLUTIONS, INC.</B></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA26><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(Name of Registrant as Specified In Its Charter)</FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA27><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>&nbsp;</B></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA28><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B><U>________________________________________________</U></B></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA29><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(Name of Person(s) Filing proxy statement, if other than the Registrant)</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA30><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA31><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Payment of Filing Fee (Check the appropriate box):</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA32><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA33><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9745;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;&nbsp;No fee required.</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA34><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA35><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;&nbsp;Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA36><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA37><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(1)&nbsp;&nbsp;Title of each class of securities to which transaction applies:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA38><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA39><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA40><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(2)&nbsp;&nbsp;Aggregate number of securities to which transaction applies:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA41><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA42><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA43><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(3)&nbsp;&nbsp;Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule&nbsp;0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA44><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA45><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA46><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(4)&nbsp;&nbsp;Proposed maximum aggregate value of transaction:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA47><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA48><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA49><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(5)&nbsp;&nbsp;Total fee paid:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA50><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA51><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<TABLE style="TEXT-INDENT: 0px; WIDTH: 100%; FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt" id=TBL58  border=0 cellSpacing=0 cellPadding=0>

<TR>
<TD style="WIDTH: 3.8%; VERTICAL-ALIGN: top">&#9744;</TD>
<TD style="WIDTH: 96.1%; VERTICAL-ALIGN: top">Fee paid previously with preliminary materials.</TD></TR>
<TR>
<TD style="WIDTH: 3.8%; VERTICAL-ALIGN: top">&nbsp;</TD>
<TD style="WIDTH: 96.1%; VERTICAL-ALIGN: top">&nbsp;</TD></TR>
<TR>
<TD style="WIDTH: 3.8%; VERTICAL-ALIGN: top">
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA56><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&#9744;</FONT></P></TD>
<TD style="WIDTH: 96.1%; VERTICAL-ALIGN: top">
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA57><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously.&nbsp; Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.</FONT></P></TD></TR></TABLE>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA59><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA60><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(1)&nbsp;&nbsp;Amount Previously Paid:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA61><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA62><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA63><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(2)&nbsp;&nbsp;Form, Schedule or Registration Statement No.:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA64><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA65><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA66><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(3)&nbsp;&nbsp;Filing Party:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA67><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA68><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA69><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">(4)&nbsp;&nbsp;Date Filed:</FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA70><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">__________________________________________________________________________________</FONT></P>
<P style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px" id=PARA91.1><FONT style="FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<DIV style="WIDTH: 100%; MARGIN-LEFT: 0pt; MARGIN-RIGHT: 0pt" id=PGBK91 >
<DIV style="TEXT-ALIGN: center; WIDTH: 100%" id=PGFTR91 >&nbsp;</DIV>
<DIV style="TEXT-ALIGN: center; WIDTH: 100%; FONT-SIZE: 10pt" id=PGNUM91 >&nbsp;</DIV>
<HR style="PAGE-BREAK-AFTER: always; WIDTH: 100%; HEIGHT: 2px; COLOR: #000000" noShade>

<DIV style="TEXT-ALIGN: left; WIDTH: 100%" id=PGHDR91 >&nbsp;</DIV></DIV>
<P style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px" id=PARA91.2><FONT style="FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt">&nbsp;</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA77><B><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">PDF Solutions, Inc.</FONT></B><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>AMENDMENT AND SUPPLEMENT TO PROXY STATEMENT</B></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA78><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>FOR THE ANNUAL MEETING OF STOCKHOLDERS</B></FONT></P>
<P style="TEXT-ALIGN: center; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA79><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"><B>TO BE HELD ON May 27, 2014</B></FONT></P>
<P style="TEXT-ALIGN: left; LINE-HEIGHT: 1.25; MARGIN: 0pt" id=PARA80><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">&nbsp;</FONT></P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px" id=PARA81><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">This amendment and supplement to the proxy statement of PDF Solutions, Inc. (the &#8220;</FONT><B>Company</B>&#8221;)<FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">, which was filed with the U.S. Securities and Exchange Commission on April 15, 2014 (the &#8220;<B>Proxy Statement</B>&#8221;), is being provided to you in connection with our Annual Meeting of Stockholders (the &#8220;<B>Annual Meeting</B>&#8221;) to be held on May 27, 2014 at <B>10:00 a.m.</B>, local time, at headquarters at, 333 West&nbsp;San Carlos Street, Suite 1000, San Jose, California 95110.</FONT></P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT>&nbsp;</P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">On May 12, 2014, Dr. Thomas Caulfield notified us that he was resigning from the Company&#8217;s Board of Directors effective as of, May 14, 2014. Dr. Caulfield is resigning because he is joining the executive team at GLOBALFOUNDRIES, Inc., one of the Company&#8217;s key customers, and not as a result of any dispute regarding the Company&#8217;s operation, policies or practices.</FONT></P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT>&nbsp;</P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">At this time, the Board is not nominating a replacement Class I director for election at the 2014 Annual Meeting. Other than Dr. Caulfield, the Class I nominees named in the 2014 Proxy Statement will stand for election at the meeting. Notwithstanding Dr. Caulfield&#8217;s resignation and withdrawal, the form of proxy card included in the Company&#8217;s definitive proxy materials remains valid. However, any votes that are or have been submitted with instruction to vote for all of the Board&#8217;s nominees will be voted only for the remaining two Class I nominees, as named in the 2014 Proxy Statement, and any votes that are or have been submitted with instruction to vote for Dr. Caulfield will be disregarded. If you have already submitted your proxy, you do not need to take any action unless you wish to change your vote.</FONT></P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT>&nbsp;</P>
<P style="TEXT-ALIGN: justify; LINE-HEIGHT: 1.25; MARGIN-TOP: 0px; TEXT-INDENT: 36pt; MARGIN-BOTTOM: 0px"><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt">This amendment and supplement should be read in conjunction with the Proxy Statement, and does not change the proposals to be acted upon at the Annual Meeting, which are described in the Proxy Statement, or the other information in the Proxy Statement.&nbsp;&nbsp;If you have already submitted your proxy, this amendment and supplement does not require that you do so again.</FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT><FONT style="FONT-FAMILY: Times New Roman, Times, serif; FONT-SIZE: 10pt"></FONT></P></BODY></HTML>
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