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13F-HR filed by WESTFIELD CAPITAL MANAGEMENT CO LP

WESTFIELD CAPITAL MANAGEMENT CO LP filed this 13F-HR for the quarter ended 2026-03-31, filed 2026-05-11, with 250 holding rows worth $23,834,799,485.

Accession
0001177719-26-000018
Filed
2026-05-11
Accepted by EDGAR
acceptance time not in the bulk data set
Ingested
Source
SEC quarterly data set

Original filing

13F report for Q1 2026

A holdings report, 250 entries on the cover page, a total value of $23,834,799,485 stated on the cover page (in dollars after the unit check, H1), rows summing to $23,834,799,485 with VALUE read as dollars as filed, 13F file number 028-10220. The quarter's positions are built on this report. The resolved quarter.

The information table after summing rows of one CUSIP and put or call (H4), with the CUSIP and issuer name as filed. Values in dollars after the unit check (method).

Issuer as filedCUSIPClassAmountValueValue read asType
NVIDIA Corp67066G104COM6,317,039$1,101,691,587dollars as filed
ASCENDIS PHARMA A/S DKK 1.0 AD04351P101SPONSORED ADR4,813,440$1,100,978,089dollars as filed
COMFORT SYS USA INC COM199908104Stock620,915$856,235,416dollars as filed
Apple Inc037833100COM3,133,113$795,152,846dollars as filed
FTAI AVIATION LTD SHSG3730V105Stock2,848,227$697,815,609dollars as filed
Microsoft Corp594918104COM1,649,513$610,600,060dollars as filed
Alphabet Inc. Reg. Shares A02079K305COM2,026,744$582,810,504dollars as filed
HOWMET AEROSPACE INC COM443201108Stock2,289,697$527,683,511dollars as filed
VERTIV HOLDINGS CO COM CL A92537N108Stock1,921,696$481,538,482dollars as filed
Amazon.com, Inc023135106COM2,279,654$474,783,586dollars as filed
AXONENTERPRISEINC05464C101STOK1,064,134$451,927,224dollars as filed
Broadcom Inc.11135F101COM1,236,925$382,840,683dollars as filed
Eli Lilly and Company532457108COM364,579$335,329,189dollars as filed
TAPESTRY INC COM876030107Stock2,198,862$310,281,358dollars as filed
META PLATFORMS INC CL A30303M102COM526,822$301,410,388dollars as filed
LPL FINL HLDGS INC COM50212V100Stock881,506$265,183,525dollars as filed
MKS INC. COM55306N104Stock1,046,763$240,556,578dollars as filed
INSMED INC COM PAR $.01457669307Stock1,468,459$240,122,429dollars as filed
VAXCYTE INC COM92243G108Stock3,646,138$211,877,079dollars as filed
ROCKETLABCORPCLASSCLASSA773121108STOK3,172,611$203,745,048dollars as filed
Netflix, Inc64110L106COM1,969,994$189,414,876dollars as filed
API GROUP CORP COM STK00187Y100Stock4,634,929$187,807,323dollars as filed
QUANTA SVCS INC74762E102COM331,816$182,173,674dollars as filed
GE Vernova Inc.36828A101COM199,306$173,974,371dollars as filed
ARES MANAGEMENT CORPORATION CL A COM STK03990B101Stock1,572,787$171,591,074dollars as filed
RHYTHM PHARMACEUTICALS INC76243J105COM1,929,123$167,775,827dollars as filed
TAIWAN SEMICONDUCTOR MFG874039100SPONSORED ADS493,504$166,779,716dollars as filed
MARVELL TECHNOLOGY INC573874104COM1,673,381$165,748,387dollars as filed
BLOOM ENERGY CORP093712107COM1,191,572$161,446,090dollars as filed
SAMSARA INC COM CL A79589L106Stock5,072,821$160,757,713dollars as filed
AMETEK INC COM031100100Stock745,832$159,876,481dollars as filed
PERMIAN RESOURCES CORP CLASS A COM71424F105Stock7,481,457$159,504,663dollars as filed
DYNATRACE INC COM NEW268150109Stock4,209,594$155,670,786dollars as filed
REVOLUTION MEDICINES INC COM76155X100Stock1,556,578$151,377,191dollars as filed
NATERA INC COM632307104Stock754,729$150,938,268dollars as filed
FABRINET SHSG3323L100Stock284,874$148,567,570dollars as filed
ABIVAX SA-00370M103SPONSORED ADS1,322,938$147,309,146dollars as filed
ServiceNow,Inc.81762P102COM1,394,187$145,762,300dollars as filed
TECHNIPFMC PLC COMG87110105Stock2,033,755$140,593,483dollars as filed
ROYAL CARIBBEAN GROUP COMV7780T103Stock505,765$139,176,354dollars as filed
HILTON WORLDWIDE HLDGS INC COM43300A203Stock457,425$139,093,786dollars as filed
Visa Inc92826C839COM456,548$137,987,039dollars as filed
CENCORA INC COM03073E105Stock436,909$137,250,518dollars as filed
ITT INC COM45073V108Stock703,309$134,001,464dollars as filed
CELSIUS HLDGS INC15118V207COM NEW3,768,911$133,720,962dollars as filed
NEXTPOWER INC CLASS A COM65290E101Stock1,107,346$133,490,560dollars as filed
CHENIERE ENERGY INC COM NEW16411R208Stock459,044$130,258,215dollars as filed
AMER SPORTS INCG0260P102COMMON STOCK3,937,521$129,623,185dollars as filed
REGAL REXNORD CORPORATION758750103COM681,717$127,658,325dollars as filed
MSCI INC COM55354G100Stock233,764$126,000,886dollars as filed
GUARDANT HEALTH INC COM40131M109Stock1,362,539$125,857,727dollars as filed
LIVE NATION ENTERTAINMENT INC COM538034109Stock810,710$123,641,351dollars as filed
Tesla Motors, Inc88160R101COM316,102$117,510,828dollars as filed
GLOBE LIFE INC37959E102COM842,423$117,240,009dollars as filed
DUTCH BROS INC26701L100CL A2,313,357$117,194,666dollars as filed
CLOUDFLARE INC CL A COM18915M107Stock541,566$111,746,725dollars as filed
ROKU INC COM CL A77543R102Stock1,178,219$111,483,082dollars as filed
XPO INC COM983793100Stock571,992$111,281,044dollars as filed
FIFTH THIRD BANCORP COM316773100Stock2,385,422$110,826,718dollars as filed
EVERPURE INC CL A74624M102Stock1,874,763$110,686,006dollars as filed
KRATOS DEFENSE & SEC SOLUTIO50077B207COM NEW1,563,146$110,217,424dollars as filed
AMERICAN INTL GROUP INC COM NEW026874784Stock1,458,711$109,768,039dollars as filed
SNOWFLAKE INC COM SHS833445109Stock718,810$108,410,941dollars as filed
PRIMORIS SVCS CORP COM74164F103Stock743,269$106,317,198dollars as filed
JONES LANG LASALLE INC COM48020Q107Stock347,779$105,836,105dollars as filed
LEGENCE CORP52476L109CL A1,861,653$105,108,928dollars as filed
LEGEND BIOTECH CORP52490G102SPONSORED ADS5,763,475$104,261,271dollars as filed
KEYCORP COM493267108Stock5,193,334$104,126,347dollars as filed
ROSS STORES INC COM778296103Stock471,916$102,231,254dollars as filed
PALOMAR HLDGS INC COM69753M105Stock854,116$102,066,862dollars as filed
PALO ALTO NETWORKS INC697435105COM636,483$102,040,950dollars as filed
DIAMONDBACK ENERGY INC COM25278X109Stock503,474$99,582,200dollars as filed
Palantir Technologies Inc. Class A69608A108COM674,557$98,674,222dollars as filed
SEMTECH CORP COM816850101Stock1,280,594$98,464,871dollars as filed
WOODWARD INC COM980745103Stock272,185$97,420,455dollars as filed
ARISTA NETWORKS INC040413205COM780,402$95,817,728dollars as filed
AUTOZONE INC COM053332102Stock28,363$95,803,684dollars as filed
SHARKNINJA INC COM SHSG8068L108Stock904,541$95,790,892dollars as filed
COHERENT CORP COM19247G107Stock396,644$94,484,681dollars as filed
ASTERA LABS INC COM04626A103COM860,113$94,268,376dollars as filed
BRAZE INC10576N102COM CL A3,973,906$93,823,921dollars as filed
JABIL INC COM466313103Stock349,209$92,760,387dollars as filed
LINCOLN ELEC HLDGS INC533900106COM358,165$89,211,738dollars as filed
IMAX CORP45245E109COM2,338,776$88,896,876dollars as filed
GENEDX HOLDINGS CORP81663L200COM CL A1,369,108$87,924,116dollars as filed
GARMIN LTD SHSH2906T109Stock376,362$87,319,632dollars as filed
CREDO TECHNOLOGY GROUP HOLDING ORDINARY SHARESG25457105Stock926,219$86,944,178dollars as filed
F5 INC COM315616102Stock298,542$86,377,157dollars as filed
EAST WEST BANCORP INC COM27579R104Stock805,956$86,043,863dollars as filed
LIFE TIME GROUP HOLDINGS INC COMMON STOCK53190C102Stock3,185,515$85,817,774dollars as filed
BIRKENSTOCK HOLDING PLCM2029K104COM SHS2,338,779$83,798,452dollars as filed
OREILLY AUTOMOTIVE INC COM67103H107Stock887,999$81,971,195dollars as filed
Morgan Stanley617446448COM496,558$81,718,617dollars as filed
XENON PHARMACEUTICALS INC COM98420N105Stock1,401,483$81,496,236dollars as filed
ALNYLAM PHARMACEUTICALS INC COM02043Q107Stock245,539$81,241,478dollars as filed
FIRSTCASH HOLDINGS INC33768G107COM431,993$81,214,684dollars as filed
IDEX CORP COM45167R104Stock426,019$80,751,901dollars as filed
MASTEC INC COM576323109Stock249,980$80,428,565dollars as filed
HOULIHAN LOKEY INC CL A441593100Stock543,611$78,073,412dollars as filed
PLEXUS CORP COM729132100Stock384,493$77,875,212dollars as filed
KARMAN HLDGS INC COMMON STOCK485924104Stock964,305$77,192,615dollars as filed
APPLIED INDL TECHNOLOGIES INC COM03820C105Stock289,201$76,730,809dollars as filed
TARGA RES CORP COM87612G101Stock304,997$76,471,806dollars as filed
CALIX INC13100M509COM1,546,101$75,743,488dollars as filed
ADAPTIVE BIOTECHNOLOGIES CORP COM00650F109Stock5,436,718$75,461,646dollars as filed
WYNN RESORTS LTD983134107COM740,013$75,148,320dollars as filed
CLEAN HARBORS INC COM184496107Stock261,092$74,862,909dollars as filed
IDEXX LABS INC COM45168D104Stock132,860$74,652,473dollars as filed
VISTRA CORP COM92840M102Stock494,875$74,394,570dollars as filed
ROCKWELL AUTOMATION INC COM773903109Stock206,277$74,028,572dollars as filed
GUIDEWIRE SOFTWARE INC COM40171V100Stock486,581$72,773,054dollars as filed
C H ROBINSON WORLDWIDE IN COM NEW12541W209Stock429,500$71,327,065dollars as filed
Lowes Companies,Inc.548661107COM300,962$71,111,190dollars as filed
NEWAMSTERDAM PHARMA CO NVN62509109COMMON STOCK2,202,913$70,515,245dollars as filed
CSX Corporation126408103COM1,658,299$68,073,166dollars as filed
ONTO INNOVATION INC COM683344105Stock326,960$67,049,687dollars as filed
DOORDASH INC CL A25809K105Stock443,921$66,654,740dollars as filed
RED ROCK RESORTS INC75700L108CL A1,228,158$65,534,511dollars as filed
CASELLA WASTE SYS INC147448104CL A822,492$65,256,515dollars as filed
PACKAGING CORP AMER COM695156109Stock303,771$64,466,282dollars as filed
WINTRUST FINL CORP COM97650W108Stock455,222$63,248,545dollars as filed
MICROCHIP TECHNOLOGY INC. COM595017104Stock970,295$62,690,760dollars as filed
MASIMO CORP COM574795100Stock341,229$60,694,349dollars as filed
ZSCALERINC98980G102STOK427,919$60,032,743dollars as filed
HEALTHEQUITY INC COM42226A107Stock712,848$59,572,707dollars as filed
DESCARTES SYS GROUP INC COM249906108Stock801,902$57,384,107dollars as filed
PROCORE TECHNOLOGIES INC COM74275K108Stock1,001,253$57,071,421dollars as filed
AVIENT CORPORATION05368V106COM1,569,468$56,971,688dollars as filed
HUBSPOTINC443573100STOK232,976$56,869,442dollars as filed
STEPSTONE GROUP INC85914M107COM CL A1,177,971$56,212,776dollars as filed
INSTALLED BLDG PRODS INC45780R101COM208,248$55,216,957dollars as filed
VITA COCO CO INC92846Q107COM1,151,933$55,189,110dollars as filed
SAIA INC78709Y105COM155,600$54,659,168dollars as filed
MOODYS CORP COM615369105Stock123,603$53,921,686dollars as filed
SYNOPSYS INC COM871607107Stock132,848$52,671,658dollars as filed
PARKER-HANNIFIN CORP COM701094104Stock58,489$52,361,692dollars as filed
LATTICE SEMICONDUCTOR CORP COM518415104Stock563,422$52,263,025dollars as filed
TOPBUILD COR COM89055F103Stock148,581$52,196,505dollars as filed
Bank of America Corp060505104COM1,066,885$52,010,644dollars as filed
GLAUKOS CORP COM377322102Stock482,219$51,915,698dollars as filed
KKR & CO INC48251W104COM558,136$51,627,609dollars as filed
COEUR MNG INC COM NEW192108504Stock2,738,846$51,408,139dollars as filed
Salesforce.com, Inc79466L302COM271,963$50,767,247dollars as filed
MARRIOTT INTL INC NEW CL A571903202Stock153,219$50,113,317dollars as filed
MADRIGAL PHARMACEUTICALS INC COM558868105Stock94,813$49,631,761dollars as filed
AFFIRM HLDGS INC COM CL A00827B106Stock1,080,636$49,514,742dollars as filed
NXP SEMICONDUCTORS N V COMN6596X109Stock247,996$48,820,570dollars as filed
HUNT J B TRANS SVCS INC COM445658107Stock228,577$48,435,504dollars as filed
DORMAN PRODS INC258278100COM461,282$48,139,390dollars as filed
TOASTINCCLASSCLASSA888787108STOK1,790,873$47,476,043dollars as filed
PLANET LABS PBC72703X106COM CL A1,637,041$45,755,296dollars as filed
BIO-TECHNE CORP09073M104COM856,043$44,736,807dollars as filed
ROBINHOOD MKTS INC770700102COM633,384$43,893,540dollars as filed
ENTEGRIS INC COM29362U104Stock371,686$43,576,502dollars as filed
RIOT PLATFORMS INC767292105COM3,499,880$43,258,517dollars as filed
FAIR ISAAC CORP COM303250104Stock39,934$42,630,713dollars as filed
TALEN ENERGY CORP COM87422Q109Stock131,461$41,966,295dollars as filed
CORPAY INC COM SHS219948106Stock143,120$41,646,618dollars as filed
MONGODB INC CL A60937P106Stock164,881$40,357,958dollars as filed
IONQ INC COM46222L108Stock1,373,788$39,606,308dollars as filed
HAMILTON LANE INC407497106CL A364,174$36,198,896dollars as filed
Micron Technology,Inc.595112103COM100,434$33,930,703dollars as filed
FREEPORT MCMORAN INC CL B35671D857Stock544,359$31,997,450dollars as filed
OPTION CARE HEALTH INC COM NEW68404L201Stock1,182,814$31,841,353dollars as filed
HAPPEN INC COM NEW52603A208Stock2,117,543$30,323,216dollars as filed
SPX TECHNOLOGIES INC78473E103COM149,276$29,846,243dollars as filed
RADNET INC750491102COM531,893$29,727,500dollars as filed
FASTENAL CO COM311900104Stock638,334$29,618,709dollars as filed
MACOM TECH SOLUTIONS HLDGS INC COM55405Y100Stock132,457$29,414,656dollars as filed
RIGETTI COMPUTING INC COMMON STOCK76655K103Stock1,895,313$26,610,195dollars as filed
Caterpillar Inc.149123101COM32,325$22,900,629dollars as filed
CORE SCIENTIFIC INC NEW21874A106COM1,480,013$22,140,994dollars as filed
URANIUM ENERGY CORP COM916896103Stock1,567,772$21,164,922dollars as filed
Danaher Corporation235851102COM110,492$20,949,283dollars as filed
ORUKA THERAPEUTICS INC COM687604108Stock313,130$15,359,027dollars as filed
TRANSDIGM GROUP INC COM893641100Stock12,950$15,008,532dollars as filed
PATTERN GROUP INC70339W104COM SER A1,172,891$14,579,035dollars as filed
Alphabet Inc. Reg. Shares C02079K107COM50,487$14,482,701dollars as filed
MUELLER INDS INC COM624756102Stock126,059$13,967,337dollars as filed
WILLIAMS COS INC COM969457100Stock181,444$13,205,494dollars as filed
APPLIED DIGITAL CORP COM NEW038169207Stock542,092$12,869,264dollars as filed
CIENA CORP COM NEW171779309Stock31,750$12,326,303dollars as filed
Coca-Cola Company191216100COM133,867$10,180,585dollars as filed
SUMITOMO MITSUI FIN GRP INC86562M209SPONSORED ADR457,584$9,037,284dollars as filed
Walmart Inc.931142103COM71,561$8,893,601dollars as filed
Johnson & Johnson478160104COM35,912$8,778,329dollars as filed
MITSUBISHI UFJ FINANCIAL GROUP SPONSORED ADS606822104ADR516,054$8,757,436dollars as filed
CUMMINS INC COM231021106Stock15,415$8,293,578dollars as filed
NextEra Energy,Inc.65339F101COM87,251$8,103,873dollars as filed
TJX Companies Inc872540109COM48,621$7,764,774dollars as filed
Wells Fargo & Company949746101COM87,713$6,982,832dollars as filed
ROLLINS INC COM775711104Stock130,617$6,976,254dollars as filed
Home Depot, Inc437076102COM20,405$6,711,000dollars as filed
Thermo Fisher Scientific Inc.883556102COM13,474$6,622,875dollars as filed
TRANE TECHNOLOGIES PLC SHSG8994E103Stock15,841$6,601,578dollars as filed
M & T BK CORP COM55261F104Stock29,839$6,168,318dollars as filed
HERSHEY CO COM427866108Stock29,158$6,061,657dollars as filed
FIRST CTZNS BANCSHARES INC DEL CL A31946M103Stock3,185$6,002,642dollars as filed
Amgen Inc.031162100COM17,052$5,999,746dollars as filed
Goldman Sachs Group,Inc.38141G104COM7,074$5,984,533dollars as filed
MCKESSON CORP COM58155Q103Stock6,901$5,971,849dollars as filed
BANCO BILBAO VIZCAYA ARGENTARI SPONSORED ADR05946K101ADR268,690$5,819,825dollars as filed
RAYMOND JAMES FINL INC COM754730109Stock40,095$5,805,355dollars as filed
McDonalds Corporation580135101COM18,034$5,604,787dollars as filed
Medtronic PlcG5960L103COM60,349$5,229,241dollars as filed
Merck & Co.,Inc.58933Y105COM42,901$5,160,561dollars as filed
Citigroup Inc.172967424COM44,457$5,041,868dollars as filed
HEICO CORP NEW422806208CL A20,130$4,249,242dollars as filed
SOUTHERN COPPER CORP84265V105COM24,124$4,150,775dollars as filed
EXPEDIA GROUP INC COM NEW30212P303Stock16,692$3,854,016dollars as filed
Pfizer Inc.717081103COM133,734$3,755,251dollars as filed
Gilead Sciences,Inc.375558103COM26,690$3,719,785dollars as filed
WATSCO INC COM942622200Stock9,822$3,573,145dollars as filed
PepsiCo,Inc.713448108COM22,760$3,534,400dollars as filed
DOMINION ENERGY INC COM25746U109Stock53,262$3,292,657dollars as filed
CARDINAL HEALTH INC14149Y108COM13,043$2,756,116dollars as filed
AbbVie,Inc.00287Y109COM10,619$2,309,526dollars as filed
GARTNERINC366651107STOK14,370$2,275,346dollars as filed
Intuitive Surgical,Inc.46120E602COM4,036$1,860,556dollars as filed
ISHARESRUSSELL1000GROWTHETF464287614STOK4,085$1,741,684dollars as filed
DEXCOM INC COM252131107Stock27,074$1,700,262dollars as filed
RANPAK HOLDINGS CORP75321W103COMMON STOCK407,328$1,454,161dollars as filed
RAMBUS INC DEL COM750917106Stock14,436$1,241,929dollars as filed
Vanguard Growth922908736COM2,443$1,066,941dollars as filed
ISHARES RUSSELL MID-CAP GROWTH ETF464287481ETF8,299$1,063,228dollars as filed
Advanced Micro Devices,Inc.007903107COM5,020$1,021,219dollars as filed
MONDAY COM LTD SHSM7S64H106Stock13,370$924,001dollars as filed
GENIUS SPORTS LIMITED SHARES CL AG3934V109Stock207,150$917,675dollars as filed
International Business Machines Corporation459200101COM3,320$804,735dollars as filed
UnitedHealth Group Inc91324P102COM2,767$748,723dollars as filed
iShares S&P 500 Growth ETF464287309SHS6,487$733,731dollars as filed
WASTE CONNECTIONS INC COM94106B101Stock4,466$725,457dollars as filed
EQT CORP COM26884L109Stock10,640$677,130dollars as filed
NOVO-NORDISK A S ADR670100205ADR17,108$628,719dollars as filed
WABTEC COM929740108Stock2,490$622,276dollars as filed
APPLOVIN CORP COM CL A03831W108Stock1,260$501,480dollars as filed
ISHARES TR464287606S&P MC 400GR ETF4,905$493,536dollars as filed
Vertex Pharmaceuticals Incorporated92532F100COM864$385,811dollars as filed
Boston Scientific Corporation101137107COM5,965$374,304dollars as filed
INSULET CORP COM45784P101Stock1,682$352,894dollars as filed
CORE NATURAL RESOURCES INC218937100COM SHS3,360$351,893dollars as filed
CAMECO CORP COM13321L108Stock3,110$337,777dollars as filed
Applied Materials,Inc.038222105COM936$319,915dollars as filed
IONIS PHARMACEUTICALS INC COM462222100Stock3,502$262,965dollars as filed
SCHOLAR ROCK HLDG CORP80706P103COM5,182$254,747dollars as filed
AVALO THERAPEUTICS INC05338F306COMMON STOCK15,639$233,490dollars as filed
STAG INDUSTRIAL INC85254J102COM6,467$233,200dollars as filed
PRAXIS PRECISION MEDICINES I74006W207COM NEW662$213,290dollars as filed
IMMUNOVANT INC45258J102COM8,581$213,152dollars as filed
PULMONX CORP745848101COM110,000$141,900dollars as filed

Amendment chain

FilingRoleFiledAcceptedIngested
13F-HR 0001177719-26-000018this filing2026-05-11acceptance time not in the bulk data set