Westfield Capital Management Co. LP

Q2 2026Q1 2026Q4 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024

In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 12, 2025), Westfield Capital Management Co. LP reported 235 stock positions worth $23.8 billion. Its top holding was Nvidia (NVDA) at 5.1% of the portfolio, followed by Ascendis Pharma A/S (ASND, 4.4%) and Microsoft (MSFT, 3.7%). Compared with Q2 2025, it opened 43 new positions, sold out of 47, added to 80 and reduced 99. The biggest buy was a new position in Marvell Technology (MRVL) and the biggest sale an exit from Salesforce (CRM).

Most Recent 13F: Q2 2026
Location: BOSTON, MA
CIK: 0001177719
Portfolio Value: $23.8B (Q3 2025)
SEC Filing: 0001177719-25-000003 ↗ filed Nov 12, 2025

Holdings Value

Holdings 235 stocks · $23.8B


NVDA Nvidia Corp.	5.09%	6,507,165	$1.2B	Reduce -13.8%
ASND Ascendis Pharma A/S	4.39%	5,259,909	$1.0B	Reduce -3.5%
MSFT Microsoft Corp.	3.71%	1,705,236	$883.2M	Reduce -3.0%
AAPL Apple Inc.	3.56%	3,334,545	$849.1M	Reduce -4.6%
FIX Comfort Systems USA Inc.	2.88%	833,195	$687.5M	Reduce -11.0%
META Meta Platforms Inc. Class A	2.37%	767,657	$563.8M	Reduce -10.6%
AMZN Amazon.com Inc.	2.34%	2,541,729	$558.1M	Reduce -18.0%
GOOGL Alphabet Inc. Class A	2.29%	2,244,650	$545.7M	Reduce -12.7%
AXON Axon Enterprise Inc.	2.20%	729,152	$523.3M	Reduce -7.7%
HWM Howmet Aerospace Inc.	1.65%	2,007,453	$393.9M	Add +4.8%
AVGO Broadcom Inc.	1.61%	1,166,362	$384.8M	Reduce -12.7%
FTAI Ftai Aviation Ltd.	1.49%	2,130,241	$355.5M	Add +11.2%
VRT Vertiv Holdings Co. Class A	1.42%	2,247,218	$339.0M	Reduce -14.8%
TDG Transdigm Group Inc.	1.21%	217,897	$287.2M	Reduce -24.9%
TPR Tapestry Inc.	1.16%	2,450,671	$277.5M	Reduce -28.3%
NFLX Netflix Inc.	1.16%	230,648	$276.5M	Reduce -8.4%
SMTC Semtech Corp.	1.01%	3,380,373	$241.5M	Add +23.1%
V Visa Inc. Class A	1.01%	705,767	$240.9M	Reduce -11.4%
NOW ServiceNow Inc.	1.00%	260,002	$239.3M	Reduce -12.8%
MRVL Marvell Technology Inc.	0.92%	2,611,958	$219.6M	New
LLY Eli Lilly & Co.	0.89%	277,005	$211.4M	Reduce -9.9%
MASI Masimo Corp.	0.88%	1,419,250	$209.4M	Add +20.1%
MRUS Merus NV	0.84%	2,132,489	$200.8M	Add +4.4%
BAC Bank of America Corp. filed as BANK AMERICA CORP	0.84%	3,861,103	$199.2M	Reduce -8.5%
LEGN Legend Biotech Corp.-ADR	0.83%	6,094,486	$198.7M	Reduce -5.8%
AZO AutoZone Inc.	0.82%	45,770	$196.4M	Add +19.9%
LPLA LPL Financial Holdings Inc.	0.80%	575,462	$191.5M	Reduce -26.4%
TSLA Tesla Inc.	0.75%	404,220	$179.8M	Reduce -7.8%
RRX Regal Rexnord Corp.	0.74%	1,221,730	$175.2M	Add +40.4%
ORCL Oracle Corp.	0.71%	600,197	$168.8M	Reduce -11.6%
RBLX Roblox Corp. Class A	0.69%	1,189,575	$164.8M	Add +4.3%
ARES Ares Management Corp. Class A	0.69%	1,027,589	$164.3M	Reduce -4.7%
GEV GE Vernova Inc.	0.69%	265,736	$163.4M	Reduce -18.3%
HQY Healthequity Inc.	0.68%	1,716,658	$162.7M	Add +35.7%
DT Dynatrace Inc.	0.68%	3,345,780	$162.1M	Add +13.3%
COHR Coherent Corp.	0.67%	1,472,963	$158.7M	Add +90.3%
CWST Casella Waste Systems Inc. Class A	0.66%	1,647,907	$156.4M	Add +6.2%
DXCM Dexcom Inc.	0.65%	2,312,210	$155.6M	Reduce -2.9%
CVLT Commvault Systems Inc.	0.62%	786,175	$148.4M	Add +135.6%
P Everpure Inc. Class A filed as PURE STORAGE INC	0.62%	1,751,558	$146.8M	Add +69.4%
SN Sharkninja Inc.	0.61%	1,402,297	$144.6M	Reduce -0.2%
BE Bloom Energy Corp. Class A	0.59%	1,675,282	$141.7M	New
IOT Samsara Inc. Class A	0.59%	3,801,787	$141.6M	Add +7.1%
PCVX Vaxcyte Inc.	0.56%	3,732,715	$134.5M	Add +21.6%
MNDY Monday.com Ltd.	0.56%	693,319	$134.3M	Add +7.3%
TSM Taiwan Semiconductor-SP ADR	0.55%	467,398	$130.5M	Reduce -19.5%
PRIM Primoris Services Corp.	0.55%	947,308	$130.1M	Add +44.8%
SNOW Snowflake Inc.	0.54%	574,955	$129.7M	Add +53.9%
RVMD Revolution Medicines Inc.	0.49%	2,513,967	$117.4M	Add +52.4%
RKLB Rocket Lab Corp.	0.49%	2,437,820	$116.8M	Add +3.1%
PCOR Procore Technologies Inc.	0.47%	1,540,265	$112.3M	Add +2.4%
PLTR Palantir Technologies Inc. Class A	0.46%	606,450	$110.6M	Add +8531.5%
ROKU Roku Inc.	0.46%	1,102,488	$110.4M	Add +0.4%
RCL Royal Caribbean Cruises Ltd.	0.46%	336,512	$108.9M	Reduce -4.5%
IP International Paper Co.	0.46%	2,341,336	$108.6M	Add +0.8%
RYTM Rhythm Pharmaceuticals Inc.	0.45%	1,069,004	$108.0M	Reduce -34.4%
DASH DoorDash Inc. Class A	0.45%	393,628	$107.1M	Add +6.9%
LYV Live Nation Entertainment Inc.	0.44%	646,370	$105.6M	Reduce -4.6%
HEI.A Heico Corp. Class A	0.44%	409,498	$104.0M	Add +13.4%
NXT Nextpower Inc. filed as NEXTRACKER INC	0.43%	1,398,057	$103.4M	Add +6.1%
NET Cloudflare Inc. Class A	0.43%	480,850	$103.2M	Add +7.2%
KRMN Karman Holdings Inc.	0.43%	1,425,576	$102.9M	New
BIRK Birkenstock Holding PLC	0.43%	2,254,493	$102.0M	Add +34.4%
COR Cencora Inc.	0.43%	325,660	$101.8M	Add +21.2%
PWR Quanta Services Inc.	0.43%	245,506	$101.7M	Add +44.4%
ITT Itt Inc.	0.43%	568,027	$101.5M	Reduce -13.6%
GKOS Glaukos Corp.	0.42%	1,231,641	$100.4M	Add +5.5%
MSCI MSCI Inc.	0.42%	175,347	$99.5M	Add +21.5%
TRU Transunion	0.41%	1,180,154	$98.9M	Add +28.0%
VST Vistra Corp.	0.40%	492,560	$96.5M	Reduce -5.2%
DSGX The Descartes Systems Grp	0.40%	1,001,331	$94.4M	Add +54.1%
NTRA Natera Inc.	0.39%	575,802	$92.7M	Reduce -14.1%
KTOS Kratos Defense & Security	0.39%	1,005,816	$91.9M	New
XPO Xpo Inc.	0.38%	694,714	$89.8M	Add +85.0%
ORLY O'reilly Automotive Inc.	0.37%	817,026	$88.1M	Add +33.4%
BLD Topbuild Corp.	0.37%	225,029	$88.0M	New
KKR KKR & Co. Inc.	0.37%	672,895	$87.4M	New
PLMR Palomar Holdings Inc.	0.36%	738,528	$86.2M	Add +81.0%
COST Costco Wholesale Corp.	0.36%	92,163	$85.3M	Reduce -36.3%
KEY Keycorp	0.35%	4,480,214	$83.7M	Reduce -4.2%
HLI Houlihan Lokey Inc.	0.35%	406,306	$83.4M	Add +17.6%
UNH Unitedhealth Group Inc.	0.35%	241,010	$83.2M	Add +4.8%
AJG Arthur J Gallagher & Co. filed as GALLAGHER ARTHUR J & CO	0.35%	267,709	$82.9M	Reduce -16.8%
DKNG Draftkings Inc. Class A	0.33%	2,080,438	$77.8M	Reduce -21.3%
ALKT Alkami Technology Inc.	0.32%	3,095,058	$76.9M	Add +160.0%
OPCH Option Care Health Inc.	0.32%	2,757,858	$76.6M	Reduce -9.9%
PANW Palo Alto Networks Inc.	0.32%	370,359	$75.4M	New
ADMA Adma Biologics Inc.	0.31%	5,106,802	$74.9M	New
BLDR Builders Firstsource Inc.	0.31%	616,032	$74.7M	New
WYNN WYNN Resorts Ltd.	0.31%	573,694	$73.6M	New
CHRW C.H. Robinson Worldwide Inc.	0.31%	550,825	$72.9M	New
VMC Vulcan Materials Co.	0.31%	236,556	$72.8M	Reduce -4.9%
GENI Genius Sports Ltd.	0.30%	5,850,083	$72.4M	Add +82.7%
FITB Fifth Third Bancorp	0.30%	1,619,948	$72.2M	Add +26.6%
RYAN Ryan Specialty Holdings Inc.	0.30%	1,278,134	$72.0M	Reduce -0.1%
OWL Blue Owl Capital Inc.	0.30%	4,228,444	$71.6M	Reduce -17.9%
ROK Rockwell Automation Inc.	0.30%	204,335	$71.4M	Reduce -4.8%
PRI Primerica Inc.	0.30%	256,774	$71.3M	Add +2.6%
PRCT Procept Biorobotics Corp.	0.29%	1,970,147	$70.3M	Add +23.3%
INSM Insmed Inc.	0.29%	487,927	$70.3M	Reduce -63.6%

Show all 235 holdings

Portfolio Sells Q2 2025 → Q3 2025


CRM Salesforce Inc.	Sold out	0.00%	−0.74
EAT Brinker International Inc.	Reduce -66.3%	0.22%	−0.71
TDG Transdigm Group Inc.	Reduce -24.9%	1.21%	−0.64
BMI Badger Meter Inc.	Sold out	0.00%	−0.63
FN Fabrinet	Reduce -75.4%	0.25%	−0.57
TXRH Texas Roadhouse Inc.	Sold out	0.00%	−0.55
AXON Axon Enterprise Inc.	Reduce -7.7%	2.20%	−0.55
CHKP Check Point Software Tech	Reduce -85.3%	0.09%	−0.54
AMAT Applied Materials Inc.	Sold out	0.00%	−0.53
LNTH Lantheus Holdings Inc.	Sold out	0.00%	−0.51
AMZN Amazon.com Inc.	Reduce -18.0%	2.34%	−0.51
PGR Progressive Corp.	Sold out	0.00%	−0.50
APO Apollo Global Management Inc.	Sold out	0.00%	−0.45
LPLA LPL Financial Holdings Inc.	Reduce -26.4%	0.80%	−0.43
ROL Rollins Inc.	Reduce -94.6%	0.02%	−0.42
GLOB Globant SA	Sold out	0.00%	−0.42
UNP Union Pacific Corp.	Sold out	0.00%	−0.39
KMPR Kemper Corp.	Sold out	0.00%	−0.35
IT Gartner Inc.	Reduce -93.3%	0.02%	−0.35
SFM Sprouts Farmers Market Inc.	Sold out	0.00%	−0.33
META Meta Platforms Inc. Class A	Reduce -10.6%	2.37%	−0.29
NOW ServiceNow Inc.	Reduce -12.8%	1.00%	−0.28
TW Tradeweb Markets Inc. Class A	Sold out	0.00%	−0.27
CART Maplebear Inc.	Reduce -96.5%	0.01%	−0.27
INSM Insmed Inc.	Reduce -63.6%	0.29%	−0.27
WIX Wix.com Ltd.	Sold out	0.00%	−0.26
NFLX Netflix Inc.	Reduce -8.4%	1.16%	−0.25
KD Kyndryl Holdings Inc.	Reduce -44.6%	0.17%	−0.25
MLTX Moonlake Immunotherapeutics	Sold out	0.00%	−0.25
SLNO Soleno Therapeutics Inc.	Reduce -37.1%	0.26%	−0.25
BFAM Bright Horizons Family Solut	Sold out	0.00%	−0.24
COST Costco Wholesale Corp.	Reduce -36.3%	0.36%	−0.24
OKTA Okta Inc.	Sold out	0.00%	−0.24
WDC Western Digital Corp.	Sold out	0.00%	−0.23
AXTA Axalta Coating Systems Ltd.	Sold out	0.00%	−0.23
DXCM Dexcom Inc.	Reduce -2.9%	0.65%	−0.22
MWA Mueller Water Products Inc. Class A	Sold out	0.00%	−0.22
VRNA Verona Pharma Ltd.	Sold out	0.00%	−0.21
CPRT Copart Inc.	Sold out	0.00%	−0.20
MTSI Macom Technology Solutions H	Reduce -38.5%	0.23%	−0.20
GEHC GE Healthcare Technology	Reduce -99.3%	0.00%	−0.19
MKC McCormick & Co.-Non VTG SHRS	Sold out	0.00%	−0.18
FLR Fluor Corp.	Sold out	0.00%	−0.18
ANF Abercrombie & Fitch Co. Class A	Sold out	0.00%	−0.18
V Visa Inc. Class A	Reduce -11.4%	1.01%	−0.18
TWLO Twilio Inc. Class A	Reduce -26.7%	0.25%	−0.17
CLS Celestica Inc.	Sold out	0.00%	−0.17
INTA Intapp Inc.	Sold out	0.00%	−0.16
DKNG Draftkings Inc. Class A	Reduce -21.3%	0.33%	−0.15
WSC Willscot Holdings Corp.	Reduce -28.4%	0.18%	−0.15

Portfolio Buys Q2 2025 → Q3 2025


MRVL Marvell Technology Inc.	New	0.92%	+0.92
BE Bloom Energy Corp. Class A	New	0.59%	+0.59
FTAI Ftai Aviation Ltd.	Add +11.2%	1.49%	+0.57
SMTC Semtech Corp.	Add +23.1%	1.01%	+0.49
PLTR Palantir Technologies Inc. Class A	Add +8531.5%	0.46%	+0.46
KRMN Karman Holdings Inc.	New	0.43%	+0.43
MRUS Merus NV	Add +4.4%	0.84%	+0.39
KTOS Kratos Defense & Security	New	0.39%	+0.39
CVLT Commvault Systems Inc.	Add +135.6%	0.62%	+0.38
COHR Coherent Corp.	Add +90.3%	0.67%	+0.38
BLD Topbuild Corp.	New	0.37%	+0.37
KKR KKR & Co. Inc.	New	0.37%	+0.37
P Everpure Inc. Class A	Add +69.4%	0.62%	+0.37
PRIM Primoris Services Corp.	Add +44.8%	0.55%	+0.33
PANW Palo Alto Networks Inc.	New	0.32%	+0.32
ADMA Adma Biologics Inc.	New	0.31%	+0.31
BLDR Builders Firstsource Inc.	New	0.31%	+0.31
WYNN WYNN Resorts Ltd.	New	0.31%	+0.31
CHRW C.H. Robinson Worldwide Inc.	New	0.31%	+0.31
RH RH	New	0.28%	+0.28
FCFS Firstcash Holdings Inc.	New	0.28%	+0.28
GL Globe Life Inc.	New	0.26%	+0.26
IDXX Idexx Laboratories Inc.	New	0.25%	+0.25
JBL Jabil Inc.	New	0.24%	+0.24
TTMI TTM Technologies	New	0.24%	+0.24
RVMD Revolution Medicines Inc.	Add +52.4%	0.49%	+0.24
AZO AutoZone Inc.	Add +19.9%	0.82%	+0.23
IMAX Imax Corp.	New	0.22%	+0.22
LSCC Lattice Semiconductor Corp.	New	0.21%	+0.21
STEP Stepstone Group Inc. Class A	New	0.21%	+0.21
RRX Regal Rexnord Corp.	Add +40.4%	0.74%	+0.21
FNB FNB Corp.	New	0.20%	+0.20
SNOW Snowflake Inc.	Add +53.9%	0.54%	+0.19
COCO The Vita Coco Co. Inc.	New	0.19%	+0.19
SLAB Silicon Laboratories Inc.	New	0.19%	+0.19
RBLX Roblox Corp. Class A	Add +4.3%	0.69%	+0.19
XPO Xpo Inc.	Add +85.0%	0.38%	+0.18
NIQ Niq Global Intelligence PLC	New	0.17%	+0.17
ALKT Alkami Technology Inc.	Add +160.0%	0.32%	+0.17
RDNT Radnet Inc.	New	0.17%	+0.17
MKSI MKS Inc.	New	0.17%	+0.17
GENI Genius Sports Ltd.	Add +82.7%	0.30%	+0.16
ALAB Astera Labs Inc.	New	0.16%	+0.16
HWM Howmet Aerospace Inc.	Add +4.8%	1.65%	+0.16
PWR Quanta Services Inc.	Add +44.4%	0.43%	+0.16
FORM Formfactor Inc.	New	0.16%	+0.16
PCVX Vaxcyte Inc.	Add +21.6%	0.56%	+0.15
ORLY O'reilly Automotive Inc.	Add +33.4%	0.37%	+0.14
RKLB Rocket Lab Corp.	Add +3.1%	0.49%	+0.14
NXT Nextpower Inc.	Add +6.1%	0.43%	+0.13

All Filings

Quarter	Positions	13F Reported Value	Top Holdings
Q2 2026	278	$30.6B	NVDA, GOOGL, ASND, AXON, FTAI
Q1 2026	250	$23.8B	NVDA, ASND, FIX, AAPL, FTAI
Q4 2025	241	$24.0B	NVDA, ASND, AAPL, MSFT, GOOGL
Q3 2025	235	$23.8B	NVDA, ASND, MSFT, AAPL, FIX
Q2 2025	239	$23.8B	NVDA, ASND, MSFT, AAPL, AMZN
Q1 2025	244	$20.5B	ASND, NVDA, AAPL, MSFT, AMZN
Q4 2024	239	$23.0B	NVDA, AAPL, MSFT, ASND, AMZN
Q3 2024	247	$22.1B	NVDA, AAPL, MSFT, ASND, AMZN
Q2 2024	248	$20.4B	NVDA, MSFT, AAPL, ASND, AMZN
Q1 2024	244	$19.0B	MSFT, ASND, AAPL, NVDA, AMZN