<?xml version="1.0" encoding="UTF-8"?><informationTable xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable">
  <infoTable>
    <nameOfIssuer>ACUITY INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>00508Y102</cusip>
    <value>25856202</value>
    <shrsOrPrnAmt>
      <sshPrnamt>68646</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>68646</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>AFFIRM HLDGS INC</nameOfIssuer>
    <titleOfClass>COM CL A</titleOfClass>
    <cusip>00827B106</cusip>
    <value>360891859</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4425406</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>4425406</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>AGILON HEALTH INC</nameOfIssuer>
    <titleOfClass>COM NEW</titleOfClass>
    <cusip>00857U206</cusip>
    <value>47228010</value>
    <shrsOrPrnAmt>
      <sshPrnamt>440642</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>440642</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ANDERSEN GROUP INC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>033853102</cusip>
    <value>63010694</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1670485</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1670485</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>API GROUP CORP</nameOfIssuer>
    <titleOfClass>COM STK</titleOfClass>
    <cusip>00187Y100</cusip>
    <value>513761106</value>
    <shrsOrPrnAmt>
      <sshPrnamt>12131313</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>12131313</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>APPLIED INDL TECHNOLOGIES IN</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>03820C105</cusip>
    <value>54803971</value>
    <shrsOrPrnAmt>
      <sshPrnamt>162070</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>162070</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>AURORA INNOVATION INC</nameOfIssuer>
    <titleOfClass>CLASS A COM</titleOfClass>
    <cusip>051774107</cusip>
    <value>74265810</value>
    <shrsOrPrnAmt>
      <sshPrnamt>10889415</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>10889415</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>BIO-TECHNE CORP</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>09073M104</cusip>
    <value>35463686</value>
    <shrsOrPrnAmt>
      <sshPrnamt>501963</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>501963</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>CARVANA CO</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>146869102</cusip>
    <value>442368453</value>
    <shrsOrPrnAmt>
      <sshPrnamt>6720882</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>6720882</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>CLEAN HARBORS INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>184496107</cusip>
    <value>266605994</value>
    <shrsOrPrnAmt>
      <sshPrnamt>892405</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>892405</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>COUPANG INC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>22266T109</cusip>
    <value>67429037</value>
    <shrsOrPrnAmt>
      <sshPrnamt>3881925</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>3881925</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>CRH PLC</nameOfIssuer>
    <titleOfClass>ORD</titleOfClass>
    <cusip>G25508105</cusip>
    <value>285186672</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2665296</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2665296</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>DOORDASH INC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>25809K105</cusip>
    <value>766571389</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4154183</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>4154183</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ENTEGRIS INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>29362U104</cusip>
    <value>52723981</value>
    <shrsOrPrnAmt>
      <sshPrnamt>293139</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>293139</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>FABRINET</nameOfIssuer>
    <titleOfClass>SHS</titleOfClass>
    <cusip>G3323L100</cusip>
    <value>339125347</value>
    <shrsOrPrnAmt>
      <sshPrnamt>603340</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>603340</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>FERGUSON ENTERPRISES INC</nameOfIssuer>
    <titleOfClass>COMMON STOCK NEW</titleOfClass>
    <cusip>31488V107</cusip>
    <value>707180508</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2979735</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2979735</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>FLOWSERVE CORP</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>34354P105</cusip>
    <value>215880057</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2911004</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2911004</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>GOOSEHEAD INS INC</nameOfIssuer>
    <titleOfClass>COM CL A</titleOfClass>
    <cusip>38267D109</cusip>
    <value>89101824</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1837151</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1837151</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MADISON AIR SOLUTIONS CORP</nameOfIssuer>
    <titleOfClass>COM SHS CL A</titleOfClass>
    <cusip>55658T105</cusip>
    <value>397662954</value>
    <shrsOrPrnAmt>
      <sshPrnamt>10196486</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>10196486</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MEDLINE INC</nameOfIssuer>
    <titleOfClass>COM CL A</titleOfClass>
    <cusip>58507V107</cusip>
    <value>103621540</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2627321</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2627321</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MERCADOLIBRE  INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>58733R102</cusip>
    <value>523921490</value>
    <shrsOrPrnAmt>
      <sshPrnamt>308663</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>308663</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>OPTION CARE HEALTH INC</nameOfIssuer>
    <titleOfClass>COM NEW</titleOfClass>
    <cusip>68404L201</cusip>
    <value>129253250</value>
    <shrsOrPrnAmt>
      <sshPrnamt>6163722</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>6163722</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>PRIVIA HEALTH GROUP INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>74276R102</cusip>
    <value>299392942</value>
    <shrsOrPrnAmt>
      <sshPrnamt>11635948</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>11635948</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>QNITY ELECTRONICS INC</nameOfIssuer>
    <titleOfClass>COMMON STOCK</titleOfClass>
    <cusip>74743L100</cusip>
    <value>743618040</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4553414</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>4553414</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>RBC BEARINGS INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>75524B104</cusip>
    <value>1100647659</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1708921</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1708921</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ROCKET COS INC</nameOfIssuer>
    <titleOfClass>COM CL A</titleOfClass>
    <cusip>77311W101</cusip>
    <value>259689749</value>
    <shrsOrPrnAmt>
      <sshPrnamt>16488238</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>16488238</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ROLLINS INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>775711104</cusip>
    <value>48655191</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1165673</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1165673</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>SHIFT4 PMTS INC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>82452J109</cusip>
    <value>215165509</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4423633</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>4423633</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>SHOPIFY INC</nameOfIssuer>
    <titleOfClass>CL A SUB VTG SHS</titleOfClass>
    <cusip>82509L107</cusip>
    <value>266689541</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2335694</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2335694</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>TWILIO INC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>90138F102</cusip>
    <value>380916748</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1846153</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1846153</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>UL SOLUTIONS INC</nameOfIssuer>
    <titleOfClass>CLASS A COM SHS</titleOfClass>
    <cusip>903731107</cusip>
    <value>299212528</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2937488</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2937488</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>VSE CORP</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>918284100</cusip>
    <value>224000835</value>
    <shrsOrPrnAmt>
      <sshPrnamt>980310</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>980310</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>WARBY PARKER INC</nameOfIssuer>
    <titleOfClass>CL A COM</titleOfClass>
    <cusip>93403J106</cusip>
    <value>194070204</value>
    <shrsOrPrnAmt>
      <sshPrnamt>6396513</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>6396513</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>WIX COM LTD</nameOfIssuer>
    <titleOfClass>SHS</titleOfClass>
    <cusip>M98068105</cusip>
    <value>92631385</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2041688</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2041688</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>XOMETRY INC</nameOfIssuer>
    <titleOfClass>CLASS A COM</titleOfClass>
    <cusip>98423F109</cusip>
    <value>97965484</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1014976</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>1014976</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>XPO INC</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>983793100</cusip>
    <value>497811622</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2424919</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <otherManager>N/A</otherManager>
    <votingAuthority>
      <Sole>2424919</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
</informationTable>
