<SEC-DOCUMENT>0000902664-25-004832.txt : 20251110
<SEC-HEADER>0000902664-25-004832.hdr.sgml : 20251110
<ACCEPTANCE-DATETIME>20251110183023
ACCESSION NUMBER:		0000902664-25-004832
CONFORMED SUBMISSION TYPE:	SCHEDULE 13D/A
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20251110
DATE AS OF CHANGE:		20251110

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MERCURY SYSTEMS INC
		CENTRAL INDEX KEY:			0001049521
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPONENTS & ACCESSORIES [3670]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				042741391
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0630

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13D/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-52823
		FILM NUMBER:		251467774

	BUSINESS ADDRESS:	
		STREET 1:		50 MINUTEMAN ROAD
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810
		BUSINESS PHONE:		9782561300

	MAIL ADDRESS:	
		STREET 1:		50 MINUTEMAN ROAD
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MERCURY COMPUTER SYSTEMS INC
		DATE OF NAME CHANGE:	19971112

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			JANA Partners Management, LP
		CENTRAL INDEX KEY:			0001998597
		ORGANIZATION NAME:           	
		EIN:				000000000
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13D/A

	BUSINESS ADDRESS:	
		STREET 1:		888 SEVENTH AVENUE
		STREET 2:		24TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10106
		BUSINESS PHONE:		212-455-0900

	MAIL ADDRESS:	
		STREET 1:		888 SEVENTH AVENUE
		STREET 2:		24TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10106
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13D/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
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    <submissionType>SCHEDULE 13D/A</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <!-- Field: Pseudo-Tag; ID: Name; Data: JANA Partners Management, LP -->
          <cik>0001998597</cik>
          <ccc>XXXXXXXX</ccc>
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      <liveTestFlag>LIVE</liveTestFlag>



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  <formData>
    <coverPageHeader>
      <amendmentNo>3</amendmentNo>
      <securitiesClassTitle>Common Stock, par value $0.01 per share</securitiesClassTitle>
      <dateOfEvent>11/06/2025</dateOfEvent>
      <previouslyFiledFlag>false</previouslyFiledFlag>
      <issuerInfo>
        <issuerCIK>0001049521</issuerCIK>
        <issuerCUSIP>589378108</issuerCUSIP>
        <issuerName>MERCURY SYSTEMS INC</issuerName>
        <address>
          <com:street1>50 Minuteman Road</com:street1>
          <com:city>Andover</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>01810</com:zipCode>
        </address>
      </issuerInfo>
      <authorizedPersons>
        <notificationInfo>
          <personName>Ele Klein &amp; Adriana Schwartz</personName>
          <personPhoneNum>212-756-2000</personPhoneNum>
          <personAddress>
            <com:street1>McDermott Will &amp; Schulte LLP</com:street1>
            <com:street2>919 Third Avenue</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10022</com:zipCode>
          </personAddress>
        </notificationInfo>
      </authorizedPersons>
    </coverPageHeader>
    <reportingPersons>
      <reportingPersonInfo>
        <reportingPersonCIK>0001998597</reportingPersonCIK>
        <reportingPersonNoCIK>N</reportingPersonNoCIK>
        <reportingPersonName>JANA Partners Management, LP</reportingPersonName>
        <fundType>AF</fundType>
        <legalProceedings>N</legalProceedings>
        <citizenshipOrOrganization>DE</citizenshipOrOrganization>
        <soleVotingPower>4966675.00</soleVotingPower>
        <sharedVotingPower>0.00</sharedVotingPower>
        <soleDispositivePower>4966675.00</soleDispositivePower>
        <sharedDispositivePower>0.00</sharedDispositivePower>
        <aggregateAmountOwned>4966675.00</aggregateAmountOwned>
        <isAggregateExcludeShares>N</isAggregateExcludeShares>
        <percentOfClass>8.3</percentOfClass>
        <typeOfReportingPerson>IA</typeOfReportingPerson>
        <typeOfReportingPerson>PN</typeOfReportingPerson>
      </reportingPersonInfo>
    </reportingPersons>
    <items1To7>
      <item1>
        <securityTitle>Common Stock, par value $0.01 per share</securityTitle>
        <issuerName>MERCURY SYSTEMS INC</issuerName>
        <issuerPrincipalAddress>
          <com:street1>50 Minuteman Road</com:street1>
          <com:city>Andover</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>01810</com:zipCode>
        </issuerPrincipalAddress>
        <commentText>This Amendment No. 3 ("Amendment No. 3") amends and supplements the statement on Schedule 13D filed with the SEC on September 22, 2022 (as amended from time to time, the "Schedule 13D") with respect to the Shares of the Issuer. This Amendment No. 3 amends Items 5 and 6 as set forth below. Capitalized terms used herein and not otherwise defined in this Amendment No. 3 have the meanings set forth in the Schedule 13D.</commentText>
      </item1>
      <item5>
        <percentageOfClassSecurities>Item 5(a) of the Schedule 13D is hereby amended and restated in its entirety as follows:

The aggregate percentage of Shares reported to be beneficially owned by the Reporting Person is based upon 60,100,136 Shares outstanding as of October 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended September 26, 2025, filed with the SEC on November 4, 2025.

As of the close of business on the date hereof, JANA may be deemed to beneficially own 4,966,675 Shares, representing approximately 8.3% of the Shares outstanding.  This includes 4,832 deferred stock units ("DSUs") granted to Mr. Ostfeld on October 23, 2024 and 2,362 DSUs granted to Mr. Ostfeld on October 22, 2025, for his service on the Board of Directors of the Issuer (the "Board"). The DSUs vest on the earlier of the first anniversary of the grant date and the next annual meeting of shareholders. Vested DSUs do not convert into Shares until the date on which Mr. Ostfeld ceases to be a member of the Board. Mr. Ostfeld has assigned all rights to any Shares issuable pursuant to the grant to the Reporting Person. Pursuant to the assignment, settlement of the award on vesting will be made to the Reporting Person.</percentageOfClassSecurities>
        <numberOfShares>Item 5(b) of the Schedule 13D is hereby amended and restated in its entirety as follows:

The Reporting Person has sole voting and dispositive power over 4,966,675 Shares, which power is exercised by the Principal.</numberOfShares>
        <transactionDesc>Item 5(c) of the Schedule 13D is hereby amended and restated in its entirety as follows:

Information concerning transactions in the Shares effected by the Reporting Person in the past sixty (60) days is set forth in Schedule A hereto and is incorporated herein by reference. All of the transactions in Shares listed therein were effected in the open market through various brokerage entities.  In addition, as disclosed in Item 5(a), on October 22, 2025, 2,362 DSUs were granted to Mr. Ostfeld for his service on the Board.</transactionDesc>
      </item5>
      <item6>
        <contractDescription>Item 6 of the Schedule 13D is hereby amended and supplemented as follows:

The information disclosed in Item 5(a) is incorporated herein by reference.</contractDescription>
      </item6>
    </items1To7>
    <signatureInfo>
      <signaturePerson>
        <signatureReportingPerson>JANA Partners Management, LP</signatureReportingPerson>
        <signatureDetails>
          <signature>/s/ Jennifer Fanjiang</signature>
          <title>Jennifer Fanjiang, Partner, Chief Legal Officer and Chief Compliance Officer</title>
          <date>11/10/2025</date>
        </signatureDetails>
      </signaturePerson>
    </signatureInfo>
  </formData>

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<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>2
<FILENAME>p25-2441schedulea.htm
<DESCRIPTION>SCHEDULE A
<TEXT>
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<HEAD>
<TITLE></TITLE>
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<BODY>


<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: right"><B><U>SCHEDULE A</U></B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>Transactions in the Shares of the Issuer in the
Past Sixty (60) Days</B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in">The following table sets forth
all transactions in the Shares effected in the past sixty (60) days by the Reporting Person. All such transactions were effected in the
open market through brokers and the price per share includes commissions.</P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0"><B>&nbsp;</B></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 11pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD STYLE="white-space: nowrap; width: 25%; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center"><B>Trade Date</B></TD>
    <TD STYLE="white-space: nowrap; width: 36%; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center"><B>Shares Purchased (Sold)</B></TD>
    <TD STYLE="white-space: nowrap; width: 39%; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center"><B>Price Per Share ($)</B></TD></TR>
  <TR STYLE="vertical-align: bottom">
    <TD STYLE="white-space: nowrap; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center">11/06/2025*</TD>
    <TD STYLE="white-space: nowrap; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center">(1,000,000)</TD>
    <TD STYLE="white-space: nowrap; padding-right: 5.4pt; padding-left: 5.4pt; text-align: center">75.45</TD></TR>
  </TABLE>
<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0">&nbsp;</P>

<P STYLE="font: 11pt Times New Roman, Times, Serif; margin: 0">* The transaction reported herein was effected for the purpose of rebalancing
the holdings of funds and accounts managed by JANA.</P>


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