<SEC-DOCUMENT>0001193125-17-244236.txt : 20170801
<SEC-HEADER>0001193125-17-244236.hdr.sgml : 20170801
<ACCEPTANCE-DATETIME>20170801160834
ACCESSION NUMBER:		0001193125-17-244236
CONFORMED SUBMISSION TYPE:	S-8
PUBLIC DOCUMENT COUNT:		3
FILED AS OF DATE:		20170801
DATE AS OF CHANGE:		20170801
EFFECTIVENESS DATE:		20170801

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ACI WORLDWIDE, INC.
		CENTRAL INDEX KEY:			0000935036
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				470772104
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		S-8
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-219608
		FILM NUMBER:		17996808

	BUSINESS ADDRESS:	
		STREET 1:		3520 KRAFT ROAD, SUITE 300
		CITY:			NAPLES
		STATE:			FL
		ZIP:			34105
		BUSINESS PHONE:		239-403-4600

	MAIL ADDRESS:	
		STREET 1:		3520 KRAFT ROAD, SUITE 300
		CITY:			NAPLES
		STATE:			FL
		ZIP:			34105

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TRANSACTION SYSTEMS ARCHITECTS INC
		DATE OF NAME CHANGE:	19950109
</SEC-HEADER>
<DOCUMENT>
<TYPE>S-8
<SEQUENCE>1
<FILENAME>d409626ds8.htm
<DESCRIPTION>S-8
<TEXT>
<HTML><HEAD>
<TITLE>S-8</TITLE>
</HEAD>
 <BODY BGCOLOR="WHITE">

 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>As filed with the Securities and Exchange Commission on August&nbsp;1, 2017 </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Registration
<FONT STYLE="white-space:nowrap">No.&nbsp;333-</FONT><U>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</U> </B></P> <P STYLE="font-size:4pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>
<P STYLE="margin-top:4pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>UNITED STATES </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES
AND EXCHANGE COMMISSION </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>Washington, D.C. 20549 </B></P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM <FONT STYLE="white-space:nowrap">S-8</FONT> </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>REGISTRATION STATEMENT </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>UNDER </I></B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>THE
SECURITIES ACT OF 1933 </I></B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>ACI WORLDWIDE, INC. </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(Exact name of registrant as specified in its charter) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
<P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:8pt" ALIGN="center">


<TR>
<TD WIDTH="50%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="48%"></TD></TR>


<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" ALIGN="center"><B>Delaware</B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"><B><FONT STYLE="white-space:nowrap">47-0772104</FONT></B></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(State or other jurisdiction of</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>incorporation or organization)</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(I.R.S. Employer</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification Number)</B></P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>3520 Kraft Rd, Suite 300</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Naples, FL</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" ALIGN="center"><B>34105</B></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="top" ALIGN="center"><B>(Address of principal executive offices)</B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top" ALIGN="center"><B>(Zip Code)</B></TD></TR>
</TABLE> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>ACI WORLDWIDE, INC. 2017 EMPLOYEE STOCK PURCHASE PLAN </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Full title of the plan) </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Dennis P. Byrnes </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Executive Vice President </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>ACI Worldwide, Inc. </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>3520
Kraft Rd., Suite 300 </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Naples, FL 34105 </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B><FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">239-403-4600</FONT></FONT> </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Name, address, and telephone number, including area code, of agent for service) </B></P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a
<FONT STYLE="white-space:nowrap">non-accelerated</FONT> filer, or a smaller reporting company. See the definitions of &#147;large accelerated filer,&#148; &#147;accelerated filer&#148; and &#147;smaller reporting company&#148; in Rule <FONT
STYLE="white-space:nowrap">12b-2</FONT> of the Exchange Act. </P> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


<TR>
<TD WIDTH="16%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="60%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="20%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="1%"></TD></TR>


<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="bottom">Large&nbsp;accelerated&nbsp;filer</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&#9746;</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom">Accelerated&nbsp;filer</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&#9744;</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="bottom">Non-accelerated filer</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&#9744;&nbsp;&nbsp;(Do not check if a smaller reporting company)</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom">Smaller&nbsp;reporting&nbsp;company</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&#9744;</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom">Emerging&nbsp;growth&nbsp;company</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom">&#9744;</TD></TR>
</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended
transition period for complying with any new or revised financial accounting standards provided pursuant to Section&nbsp;7(a)(2)(B) of the Securities Act. &nbsp;&nbsp;&#9744; </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>CALCULATION OF REGISTRATION FEE </B></P> <P STYLE="font-size:4pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:8pt" ALIGN="center">


<TR>
<TD WIDTH="44%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="13%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="13%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="13%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="13%"></TD></TR>


<TR STYLE="font-size:1px; ">
<TD COLSPAN="9" VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000">&nbsp;</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><B>Title of Securities <BR>To Be Registered</B></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Amount</B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>To Be</B></P> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Registered
(1)(2)</B></P></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Proposed</B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Maximum</B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Offering
Price</B></P> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Per Share (3)</B></P></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Proposed</B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Maximum</B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Aggregate</B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Offering</B></P> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Price</B></P></TD>

<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Amount Of</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Registration Fee</B></P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Common Stock, par value $.005 per share</P></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="right" STYLE="BORDER-TOP:1px solid #000000">3,000,000</TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000">$23.56</TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000">$70,680,000</TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000">&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000">$8,191.81</TD></TR>
<TR STYLE="font-size:1px; ">
<TD COLSPAN="9" VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000">&nbsp;</P></TD></TR>
<TR STYLE="font-size:1px; ">
<TD COLSPAN="9" VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000">&nbsp;</P></TD></TR>
</TABLE>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">(1)</TD>
<TD ALIGN="left" VALIGN="top">This Registration Statement covers 3,000,000 shares of Common Stock, par value $0.005 per share, of ACI Worldwide, Inc. (the &#147;Registrant&#148;) available for awards under the ACI Worldwide, Inc. 2017 Employee Stock
Purchase Plan. </TD></TR></TABLE>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">(2)</TD>
<TD ALIGN="left" VALIGN="top">Pursuant to Rule 416 under the Securities Act, this Registration Statement also covers an indeterminate number of additional shares that may be offered or issued pursuant to the above-named plan by reason of any stock
dividend, stock split, recapitalization or any other similar transaction without the receipt of consideration which results in an increase in the number of the Registrant&#146;s outstanding shares of common stock. </TD></TR></TABLE>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">(3)</TD>
<TD ALIGN="left" VALIGN="top">Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(c) and (h)&nbsp;promulgated under the Securities Act.&nbsp;The fee is calculated on the basis of the average of the high and low
sale prices of the Registrant&#146;s common stock on July&nbsp;28, 2017, of $24.05 and $23.06 respectively, as reported on the NASDAQ Global Select Market. </TD></TR></TABLE> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>

<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">

 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>PART I </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;1.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Plan Information.* </B></TD></TR></TABLE> <P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;2.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Registrant Information and Employee Plan Annual Information.* </B></TD></TR></TABLE> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">*</TD>
<TD ALIGN="left" VALIGN="top">Information required by Part I to be contained in the Section&nbsp;10(a) prospectus is omitted from this Registration Statement in accordance with Instruction G of Form <FONT STYLE="white-space:nowrap">S-8</FONT> and
Rule 428(b)(1) under the Securities Act, and the introductory note to Part I of Form <FONT STYLE="white-space:nowrap">S-8.</FONT> </TD></TR></TABLE>
<P STYLE="margin-top:24pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>PART II </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INFORMATION
REQUIRED IN THE REGISTRATION STATEMENT </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;3.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Incorporation of Documents by Reference. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:8%; font-size:10pt; font-family:Times New Roman">The following documents, which have been filed
by the Registrant pursuant to the Securities Exchange Act of 1934 (the &#147;Exchange Act&#148;) or as otherwise indicated, are hereby incorporated by reference into this Registration Statement and shall be deemed to be a part hereof: </P>
<P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="5%">&nbsp;</TD>
<TD WIDTH="2%" VALIGN="top" ALIGN="left">&#149;</TD>
<TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
<TD ALIGN="left" VALIGN="top">The Registrant&#146;s Annual Report on Form <FONT STYLE="white-space:nowrap">10-K</FONT> for the fiscal year ended December&nbsp;31, 2016 filed with the SEC on March&nbsp;1, 2017; </TD></TR></TABLE>
<P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="5%">&nbsp;</TD>
<TD WIDTH="2%" VALIGN="top" ALIGN="left">&#149;</TD>
<TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
<TD ALIGN="left" VALIGN="top">All other reports filed by the Registrant pursuant to Section&nbsp;13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;), since December&nbsp;31, 2016; and </TD></TR></TABLE>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">2 </P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">


<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="5%">&nbsp;</TD>
<TD WIDTH="2%" VALIGN="top" ALIGN="left">&#149;</TD>
<TD WIDTH="1%" VALIGN="top">&nbsp;</TD>
<TD ALIGN="left" VALIGN="top">The description of the Registrant&#146;s Class&nbsp;A Common Stock (reclassified as &#147;Common Stock&#148;) set forth under the caption &#147;Description of Capital Stock&#151;Common Stock&#148; in the
Registrant&#146;s Registration Statement on Form <FONT STYLE="white-space:nowrap">S-4</FONT> (File <FONT STYLE="white-space:nowrap">No.&nbsp;333-56309)</FONT> filed with the SEC on June&nbsp;8, 1998. </TD></TR></TABLE>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:8%; font-size:10pt; font-family:Times New Roman">All documents subsequently filed by the Registrant pursuant to Sections&nbsp;13(a), 13(c), 14 and 15(d) of the Exchange Act (other than any
portion of such filings that are furnished under applicable SEC rules rather than filed) prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated herein by reference and shall be deemed a part hereof from the date of filing of such documents. Any statement contained in a document incorporated or deemed to be incorporated by reference herein will be
deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which is or is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement. </P>
<P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;4.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Description of Securities. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Not applicable. </P>
<P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;5.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Interests of Named Experts and Counsel. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Not applicable. </P>
<P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;6.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Indemnification of Directors and Officers. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:8%; font-size:10pt; font-family:Times New Roman">Section&nbsp;145 of the General Corporation
Law of the State of Delaware (the &#147;DGCL&#148;) permits indemnification by a corporation of certain officers, directors, employees and agents. Consistent therewith, Article X of the Amended and Restated Certificate of Incorporation of the
Registrant provides that the Registrant shall, to the fullest extent permitted or required by the DGCL, as the same exists or may hereafter be amended (but, in the case of any such amendment, only to the extent that such amendment permits the
Registrant to provide broader indemnification rights than such law permitted the Registrant to provide prior to such amendment), indemnify a director or officer of the Registrant or a person who is or was serving at the request of the Registrant as
a director, officer, employee or agent of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to an employee benefit plan, who was or is made (or threatened to be made) a party to or is
otherwise involved in a civil, criminal, administrative or investigative action suit or proceeding (an &#147;indemnified person&#148;). Article X also provides that expenses incurred by an indemnified person will be paid in advance by the
Registrant; provided, however, that, if the DCGL requires, an advancement of expenses incurred by an indemnified person in his or her capacity as a director or officer will be made only if the Registrant receives an undertaking by or on behalf of
the indemnified person to repay all amounts so advanced if it shall ultimately be determined by final judicial decision from which there is no further right to appeal that such indemnified person is not entitled to be indemnified for such expenses.
The Amended and Restated Certificate of Incorporation also authorizes the Registrant to maintain officer and director liability insurance, and such a policy is currently in effect. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">The Registrant has entered into Indemnification Agreements with each of its executive officers and certain other employees. Under the
Indemnification Agreements, the Registrant agrees to indemnify the employee to the fullest extent permitted by law if the employee was, is or becomes a party to or witness or other participant in any threatened, pending or completed action, suit,
proceeding or alternative dispute resolution mechanism, or any hearing, inquiry or investigation by reason of (or arising in part out of) any event or occurrence related to the fact that the employee is or was a director, officer, employee, agent or
fiduciary of the Registrant, or any subsidiary of the Registrant, or is or was serving at the request of the Registrant as a director, officer, employee, agent or fiduciary of another corporation, partnership, joint venture, trust or other
enterprise, or by reason of any action or inaction on the part of the employee while serving in such capacity. The Registrant also agrees, to the extent the Registrant maintains liability insurance applicable to directors, officers, employees,
agents or fiduciaries, the employee will be covered by such policies as to provide the employee the same rights and benefits as are accorded to the most favorably similarly situated insured. </P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">3 </P>


<p Style='page-break-before:always'>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; text-indent:8%; font-size:10pt; font-family:Times New Roman">The above discussion of the DGCL and the Registrant&#146;s Amended and Restated Certificate of
Incorporation is not intended to be exhaustive and is qualified in its entirety by such statute and the Amended and Restated Certificate of Incorporation. </P> <P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;7.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Exemption from Registration Claimed. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Not applicable. </P>
<P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;8.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Exhibits. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Reference is made to the Exhibit Index. </P>
<P STYLE="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><B>Item&nbsp;9.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Undertakings. </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(a) The undersigned Registrant hereby undertakes: </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; font-size:10pt; font-family:Times New Roman">(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this Registration Statement: </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:8%; font-size:10pt; font-family:Times New Roman">(i) To include any prospectus required by section 10(a)(3) of the Securities Act of 1933; </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:8%; font-size:10pt; font-family:Times New Roman">(ii) To reflect in the prospectus any facts or events arising after the effective date of this Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this Registration Statement. Notwithstanding the foregoing, any increase or decrease in volume of securities
offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the
Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20&nbsp;percent change in the maximum aggregate offering price set forth in the &#147;Calculation of Registration Fee&#148; table in the
effective Registration Statement; </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:8%; font-size:10pt; font-family:Times New Roman">(iii) To include any material information with respect to the plan of distribution not previously
disclosed in this Registration Statement or any material change to such information in this Registration Statement; </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">provided, however, that paragraphs
(a)(1)(i) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section&nbsp;13 or
15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in this Registration Statement. </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; font-size:10pt; font-family:Times New Roman">(2) That, for the purpose
of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall
be deemed to be the initial bona fide offering thereof. </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; margin-left:4%; font-size:10pt; font-family:Times New Roman">(3) To remove from registration by means of a post-effective amendment any of the
securities being registered which remain unsold at the termination of the offering. </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">(b) the Registrant hereby undertakes that, for purposes of determining
any liability under the Securities Act of 1933, each filing of the Registrant&#146;s annual report pursuant to Section&nbsp;13(a) or Section&nbsp;15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit
plan&#146;s annual report pursuant to Section&nbsp;15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in this Registration Statement shall be deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. </P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">4 </P>


<p Style='page-break-before:always'>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">
(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing
provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is
asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue. </P>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">5 </P>


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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>SIGNATURES </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on <FONT STYLE="white-space:nowrap">Form&nbsp;S-8</FONT> and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Naples, State of Florida, on
August&nbsp;1, 2017. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><DIV ALIGN="right">
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="40%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">


<TR>
<TD WIDTH="6%"></TD>
<TD VALIGN="bottom" WIDTH="2%"></TD>
<TD WIDTH="92%"></TD></TR>


<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" COLSPAN="3"><B>ACI WORLDWIDE, INC.</B></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top">By:</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Dennis P. Byrnes</P></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">Name: Dennis P. Byrnes</TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">Title: Executive Vice President</TD></TR>
</TABLE></DIV>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">6 </P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">

 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>POWER OF ATTORNEY </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Each person whose signature appears below constitutes and appoints Dennis P. Byrnes and Scott W. Behrens, and each of them, his or her true
and lawful <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents with full power of substitution and resubstitution, for him or her and in his or her name, place, and stead, in any and all
capacities, to sign any and all amendments (including post-effective amendments) and additions to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, and hereby grants to such <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents full power and authority to do and perform each and every act and thing requisite and
necessary to be done, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and
agents or their substitute or substitutes may lawfully do or cause to be done by virtue hereof. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the
Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the date indicated. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">


<TR>
<TD WIDTH="37%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="44%"></TD>
<TD VALIGN="bottom" WIDTH="2%"></TD>
<TD WIDTH="15%"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:33.30pt; font-size:8pt; font-family:Times New Roman"><B>Signature</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Title</B></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Date</B></P></TD></TR>


<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Philip G. Heasley</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Philip G. Heasley</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">President, Chief Executive Officer and Director</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman"><I>(Principal Executive Officer)</I></P></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Scott W. Behrens</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Scott W. Behrens</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Senior Executive Vice President and Chief Financial Officer <I>(Principal Financial Officer and Principal Accounting Officer)</I></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ David A. Poe</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">David A. Poe</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Chairman of the Board of Directors and Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Janet O. Estep</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Janet O. Estep</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ James C. Hale</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">James C. Hale</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ James C. McGroddy</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">James C. McGroddy</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Charles E. Peters, Jr.</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Charles E. Peters, Jr.</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Adalio T. Sanchez</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Adalio T. Sanchez</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ John M. Shay, Jr.</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">John M. Shay, Jr.</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
</TABLE>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">7 </P>


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<TR>
<TD WIDTH="37%"></TD>
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<TD WIDTH="44%"></TD>
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<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
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<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Jan H. Suwinski</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Jan H. Suwinski</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Thomas W. Warsop III</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Thomas W. Warsop III</P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Director</TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="top">August&nbsp;1, 2017</TD></TR>
</TABLE>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">8 </P>


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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>EXHIBIT INDEX </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">


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<TD></TD>
<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD WIDTH="90%"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:39.10pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Exhibit&nbsp;No.</B></P></TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:39.50pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Description</B></P></TD></TR>


<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;3.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Amended and Restated Certificate of Incorporation of Registrant (incorporated herein by reference to</P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Exhibit 3.1 to the Registrant&#146;s Current Report on Form <FONT STYLE="white-space:nowrap">8-K</FONT> filed with the Commission on June&nbsp;24,
2014)</P></TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;3.2</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Amended and Restated Bylaws of Registrant (incorporated herein by reference to Exhibit 3.1 to the Registrant&#146;s current report on Form <FONT STYLE="white-space:nowrap">8-K</FONT> filed with the Commission on February&nbsp;27,
2017)</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;4.1</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">ACI Worldwide, Inc. 2017 Employee Stock Purchase Plan (incorporated herein by reference to Annex A to the Registrant&#146;s Proxy Statement filed with the Commission on April&nbsp;27, 2017)</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>&nbsp;&nbsp;5.1*</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Opinion of Koley Jessen, P.C., L.L.O. (as to the validity of the securities being registered)</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>23.1*</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Consent of Deloitte&nbsp;&amp; Touche LLP</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>23.2*</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Consent of Koley Jessen, P.C., L.L.O. (included in Exhibit 5.1)</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top" NOWRAP>24*</TD>
<TD VALIGN="bottom">&nbsp;&nbsp;</TD>
<TD VALIGN="top">Power of Attorney (included on the signature page of the Registration Statement)</TD></TR>
</TABLE> <P STYLE="line-height:8.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000;width:10%">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR style = "page-break-inside:avoid">
<TD WIDTH="4%" VALIGN="top" ALIGN="left">*</TD>
<TD ALIGN="left" VALIGN="top">filed herewith </TD></TR></TABLE>
 <p STYLE="margin-top:0pt;margin-bottom:0pt ; font-size:8pt">&nbsp;</P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">9 </P>

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<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>d409626dex51.htm
<DESCRIPTION>EX-5.1
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Exhibit 5.1 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>[Koley Jessen P.C., L.L.O. Letterhead] </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center">August&nbsp;1, 2017 </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">ACI Worldwide, Inc. </P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">3520 Kraft Rd, Suite </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">300 Naples, FL 34105 </P>
<P STYLE="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TR style = "page-break-inside:avoid">
<TD WIDTH="5%" VALIGN="top" ALIGN="left">Re:</TD>
<TD ALIGN="left" VALIGN="top">Registration Statement on Form S-8 Filed by ACI Worldwide, Inc. </TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Ladies and Gentlemen: </P>
<P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">We have acted as counsel for ACI Worldwide, Inc., a Delaware corporation (the &#147;<B><I>Company</I></B>&#148;), in connection with the
registration of 3,000,000 shares (the &#147;<B><I>Shares</I></B>&#148;) of the Company&#146;s Common Stock, par value $0.005 per share, issuable pursuant to the ACI Worldwide, Inc. 2017 Employee Stock Purchase Plan (the
&#147;<B><I>Plan</I></B>&#148;). In connection with the opinion expressed herein, we have examined such documents, records and matters of law as we have deemed relevant or necessary for purposes of this opinion. Based on the foregoing, and subject
to the further limitations, qualifications and assumptions set forth herein, we are of the opinion that the Shares that may be issued or delivered and sold pursuant to the Plan and the authorized forms of stock option, restricted share award,
performance share award or other applicable award agreements thereunder will be, when issued or delivered and sold in accordance with the Plan and such agreements, validly issued, fully paid and nonassessable, provided that the consideration for
such shares is at least equal to the stated par value thereof. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">The opinion expressed herein is limited to the General Corporation Law of
the State of Delaware, as currently in effect, and we express no opinion as to the effect of the laws of any other jurisdiction. In addition, we have assumed that the resolutions authorizing the Company to issue or deliver and sell the Shares
pursuant to the Plan and the applicable award agreements will be in full force and effect at all times at which the Shares are issued or delivered or sold by the Company, and the Company will take no action inconsistent with such resolutions. </P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">In rendering the opinion above, we have assumed that each award under the Plan will be approved by the Board of Directors of the Company or an
authorized committee of the Board of Directors. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">We hereby consent to the filing of this opinion as Exhibit 5.1 to the Registration
Statement on Form S-8 filed by the Company to effect registration of the Shares to be issued or delivered and sold pursuant to the Plan under the Securities Act of 1933 (the &#147;<B><I>Act</I></B>&#148;). In giving such consent, we do not thereby
admit that we are included in the category of persons whose consent is required under Section&nbsp;7 of the Act or the rules and regulations of the Securities and Exchange Commission promulgated thereunder. </P>
<P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><DIV ALIGN="right">
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<TR>
<TD WIDTH="100%"></TD></TR>


<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top">Sincerely,</TD></TR>
<TR STYLE="font-size:1pt">
<TD HEIGHT="16"></TD></TR>
<TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<TD VALIGN="top">/s/ Koley Jessen P.C., L.L.O.</TD></TR>
</TABLE></DIV>
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<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>3
<FILENAME>d409626dex231.htm
<DESCRIPTION>EX-23.1
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<TITLE>EX-23.1</TITLE>
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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Exhibit 23.1 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">We consent to the incorporation by reference in this Registration Statement on Form S-8 of our reports dated March&nbsp;1, 2017, relating to the consolidated
financial statements of ACI Worldwide, Inc. and subsidiaries (the &#147;Company&#148;), and the effectiveness of the Company&#146;s internal control over financial reporting, appearing in the Annual Report on Form 10-K of the Company for the year
ended December&nbsp;31, 2016. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><I>/s/ DELOITTE&nbsp;&amp; TOUCHE LLP </I></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Omaha, Nebraska </P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">August&nbsp;1, 2017 </P>
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