Westfield Capital Management Co. LP
In its 13F for Q4 2025 (holdings as of December 31, 2025, filed February 11, 2026), Westfield Capital Management Co. LP reported 241 stock positions worth $24.0 billion. Its top holding was Nvidia (NVDA) at 4.6% of the portfolio, followed by Ascendis Pharma A/S (ASND, 4.6%) and Apple (AAPL, 3.7%). Compared with Q3 2025, it opened 39 new positions, sold out of 33, added to 117 and reduced 71. The biggest buy was a new position in Abivax SA-ADR (ABVX) and the biggest sale Transdigm (TDG, shares −93%).
- Most Recent 13F
- Q2 2026
- Location
- BOSTON, MA
- CIK
- 0001177719
- Portfolio Value
- $24.0B (Q4 2025)
- SEC Filing
- 0001177719-26-000005 ↗ filed Feb 11, 2026
Holdings Value
Holdings 241 stocks · $24.0B
| NVDA Nvidia Corp. | 4.62% | 5,951,049 | $1.1B | Reduce -8.6% |
| ASND Ascendis Pharma A/S | 4.61% | 5,185,696 | $1.1B | Reduce -1.4% |
| AAPL Apple Inc. | 3.71% | 3,274,318 | $890.2M | Reduce -1.8% |
| MSFT Microsoft Corp. | 3.27% | 1,621,219 | $784.1M | Reduce -4.9% |
| GOOGL Alphabet Inc. Class A | 2.84% | 2,178,478 | $681.9M | Reduce -3.0% |
| FIX Comfort Systems USA Inc. | 2.60% | 668,835 | $624.2M | Reduce -19.7% |
| AMZN Amazon.com Inc. | 2.24% | 2,330,770 | $538.0M | Reduce -8.3% |
| AXON Axon Enterprise Inc. | 1.97% | 831,177 | $472.1M | Add +14.0% |
| FTAI Ftai Aviation Ltd. | 1.93% | 2,350,625 | $462.7M | Add +10.3% |
| HWM Howmet Aerospace Inc. | 1.90% | 2,219,125 | $455.0M | Add +10.5% |
| META Meta Platforms Inc. Class A | 1.80% | 655,283 | $432.5M | Reduce -14.6% |
| AVGO Broadcom Inc. | 1.60% | 1,112,318 | $385.0M | Reduce -4.6% |
| VRT Vertiv Holdings Co. Class A | 1.54% | 2,277,716 | $369.0M | Add +1.4% |
| LLY Eli Lilly & Co. | 1.24% | 277,549 | $298.3M | Add +0.2% |
| TPR Tapestry Inc. | 1.12% | 2,098,104 | $268.1M | Reduce -14.4% |
| RVMD Revolution Medicines Inc. | 0.94% | 2,845,013 | $226.6M | Add +13.2% |
| NOW ServiceNow Inc. | 0.94% | 1,476,803 | $226.2M | Add +13.6% |
| LPLA LPL Financial Holdings Inc. | 0.93% | 625,562 | $223.4M | Add +8.7% |
| V Visa Inc. Class A | 0.88% | 603,926 | $211.8M | Reduce -14.4% |
| BAC Bank of America Corp. filed as BANK AMERICA CORP | 0.88% | 3,823,609 | $210.3M | Reduce -1.0% |
| TSLA Tesla Inc. | 0.86% | 461,675 | $207.6M | Add +14.2% |
| MASI Masimo Corp. | 0.82% | 1,522,049 | $198.0M | Add +7.2% |
| ARES Ares Management Corp. Class A | 0.78% | 1,151,200 | $186.1M | Add +12.0% |
| AME Ametek Inc. | 0.77% | 900,216 | $184.8M | Add +151.0% |
| RKLB Rocket Lab Corp. | 0.75% | 2,592,443 | $180.8M | Add +6.3% |
| SMTC Semtech Corp. | 0.75% | 2,448,612 | $180.4M | Reduce -27.6% |
| HQY Healthequity Inc. | 0.75% | 1,952,452 | $178.9M | Add +13.7% |
| FITB Fifth Third Bancorp | 0.73% | 3,746,926 | $175.4M | Add +131.3% |
| AZO AutoZone Inc. | 0.72% | 51,122 | $173.4M | Add +11.7% |
| MRVL Marvell Technology Inc. | 0.69% | 1,947,807 | $165.5M | Reduce -25.4% |
| NTRA Natera Inc. | 0.68% | 714,692 | $163.7M | Add +24.1% |
| PCVX Vaxcyte Inc. | 0.68% | 3,539,717 | $163.3M | Reduce -5.2% |
| CWST Casella Waste Systems Inc. Class A | 0.68% | 1,665,226 | $163.1M | Add +1.1% |
| NFLX Netflix Inc. | 0.62% | 1,597,547 | $149.8M | Reduce -30.7% |
| DT Dynatrace Inc. | 0.61% | 3,356,708 | $145.5M | Add +0.3% |
| SNOW Snowflake Inc. | 0.59% | 649,105 | $142.4M | Add +12.9% |
| HUBS HubSpot Inc. | 0.59% | 352,154 | $141.3M | Add +162.5% |
| IOT Samsara Inc. Class A | 0.58% | 3,953,970 | $140.2M | Add +4.0% |
| ABVX Abivax SA-ADR | 0.57% | 1,009,966 | $136.2M | New |
| RYTM Rhythm Pharmaceuticals Inc. | 0.56% | 1,267,158 | $135.6M | Add +18.5% |
| TSM Taiwan Semiconductor-SP ADR | 0.56% | 446,195 | $135.6M | Reduce -4.5% |
| MKSI MKS Inc. | 0.56% | 839,773 | $134.2M | Add +159.7% |
| LEGN Legend Biotech Corp.-ADR | 0.56% | 6,164,677 | $134.0M | Add +1.1% |
| CVLT Commvault Systems Inc. | 0.55% | 1,057,077 | $132.5M | Add +34.5% |
| WGS Genedx Holdings Corp. | 0.55% | 1,018,261 | $132.4M | Add +87.2% |
| APG Api Group Corp. | 0.55% | 3,453,355 | $132.1M | New |
| TEAM Atlassian Corp. Class A | 0.55% | 812,215 | $131.7M | Add +151.9% |
| ADMA Adma Biologics Inc. | 0.53% | 6,992,907 | $127.6M | Add +36.9% |
| RRX Regal Rexnord Corp. | 0.52% | 893,100 | $125.3M | Reduce -26.9% |
| RCL Royal Caribbean Cruises Ltd. | 0.52% | 448,653 | $125.1M | Add +33.3% |
| COHR Coherent Corp. | 0.51% | 665,123 | $122.8M | Reduce -54.8% |
| ROKU Roku Inc. | 0.50% | 1,112,478 | $120.7M | Add +0.9% |
| MSCI MSCI Inc. | 0.50% | 207,792 | $119.2M | Add +18.5% |
| PRIM Primoris Services Corp. | 0.49% | 952,196 | $118.2M | Add +0.5% |
| GEV GE Vernova Inc. | 0.48% | 177,934 | $116.3M | Reduce -33.0% |
| PWR Quanta Services Inc. | 0.48% | 273,528 | $115.4M | Add +11.4% |
| PLMR Palomar Holdings Inc. | 0.47% | 840,226 | $113.2M | Add +13.8% |
| LYV Live Nation Entertainment Inc. | 0.46% | 775,234 | $110.5M | Add +19.9% |
| PODD Insulet Corp. | 0.46% | 386,468 | $109.8M | Add +91.9% |
| BROS Dutch Bros Inc. Class A | 0.45% | 1,779,616 | $108.9M | New |
| COR Cencora Inc. | 0.45% | 319,215 | $107.8M | Reduce -2.0% |
| BLD Topbuild Corp. | 0.44% | 255,451 | $106.6M | Add +13.5% |
| DSGX The Descartes Systems Grp | 0.44% | 1,193,869 | $104.7M | Add +19.2% |
| HEI.A Heico Corp. Class A | 0.43% | 412,041 | $104.0M | Add +0.6% |
| HLT Hilton Worldwide Holdings Inc. | 0.43% | 357,721 | $102.8M | Add +53.1% |
| NET Cloudflare Inc. Class A | 0.43% | 519,475 | $102.4M | Add +8.0% |
| ITT Itt Inc. | 0.42% | 587,446 | $101.9M | Add +3.4% |
| P Everpure Inc. Class A filed as PURE STORAGE INC | 0.42% | 1,520,219 | $101.9M | Reduce -13.2% |
| IDXX Idexx Laboratories Inc. | 0.42% | 147,447 | $99.8M | Add +56.6% |
| BE Bloom Energy Corp. Class A | 0.41% | 1,145,296 | $99.5M | Reduce -31.6% |
| XPO Xpo Inc. | 0.41% | 724,214 | $98.4M | Add +4.3% |
| EWBC East West Bancorp Inc. | 0.41% | 874,152 | $98.2M | Add +48.3% |
| DASH DoorDash Inc. Class A | 0.40% | 425,080 | $96.3M | Add +8.0% |
| ABBV Abbvie Inc. | 0.40% | 419,784 | $95.9M | Add +5194.9% |
| DXCM Dexcom Inc. | 0.40% | 1,439,689 | $95.6M | Reduce -37.7% |
| ALKT Alkami Technology Inc. | 0.40% | 4,118,355 | $95.0M | Add +33.1% |
| NXT Nextpower Inc. | 0.40% | 1,090,300 | $95.0M | Reduce -22.0% |
| KTOS Kratos Defense & Security | 0.39% | 1,245,587 | $94.6M | Add +23.8% |
| SN Sharkninja Inc. | 0.39% | 840,060 | $94.0M | Reduce -40.1% |
| ORCL Oracle Corp. | 0.39% | 474,397 | $92.5M | Reduce -21.0% |
| ROK Rockwell Automation Inc. | 0.38% | 233,795 | $91.0M | Add +14.4% |
| HLI Houlihan Lokey Inc. | 0.38% | 520,002 | $90.6M | Add +28.0% |
| CHRW C.H. Robinson Worldwide Inc. | 0.37% | 556,472 | $89.5M | Add +1.0% |
| OPCH Option Care Health Inc. | 0.37% | 2,765,305 | $88.1M | Add +0.3% |
| BURL Burlington Stores Inc. | 0.36% | 302,307 | $87.3M | Add +46.8% |
| FTI Technipfmc PLC | 0.36% | 1,952,427 | $87.0M | Add +31.9% |
| ORLY O'reilly Automotive Inc. | 0.36% | 952,702 | $86.9M | Add +16.6% |
| IMAX Imax Corp. | 0.36% | 2,346,486 | $86.7M | Add +44.6% |
| FN Fabrinet | 0.36% | 190,170 | $86.6M | Add +16.7% |
| VST Vistra Corp. | 0.36% | 533,945 | $86.1M | Add +8.4% |
| FCFS Firstcash Holdings Inc. | 0.36% | 537,734 | $85.7M | Add +27.3% |
| GL Globe Life Inc. | 0.35% | 608,813 | $85.1M | Add +41.4% |
| PR Permian Resources Corp. Class A | 0.35% | 5,951,186 | $83.5M | Add +77.2% |
| KEY Keycorp | 0.35% | 4,040,297 | $83.4M | Reduce -9.8% |
| PANW Palo Alto Networks Inc. | 0.34% | 448,460 | $82.6M | Add +21.1% |
| DKNG Draftkings Inc. Class A | 0.34% | 2,383,054 | $82.1M | Add +14.6% |
| LECO Lincoln Electric Holdings | 0.34% | 337,725 | $80.9M | Add +19.4% |
| PCOR Procore Technologies Inc. | 0.33% | 1,105,325 | $80.4M | Reduce -28.2% |
| TRU Transunion | 0.33% | 933,553 | $80.1M | Reduce -20.9% |
| BIRK Birkenstock Holding PLC | 0.33% | 1,954,801 | $80.0M | Reduce -13.3% |
Portfolio Sells Q3 2025 → Q4 2025
| TDG Transdigm Group Inc. | Reduce -92.6% | 0.09% | −1.12 |
| MRUS Merus NV | Sold out | 0.00% | −0.84 |
| META Meta Platforms Inc. Class A | Reduce -14.6% | 1.80% | −0.56 |
| MNDY Monday.com Ltd. | Reduce -98.0% | 0.01% | −0.55 |
| NFLX Netflix Inc. | Reduce -30.7% | 0.62% | −0.54 |
| RBLX Roblox Corp. Class A | Reduce -61.2% | 0.16% | −0.54 |
| NVDA Nvidia Corp. | Reduce -8.6% | 4.62% | −0.47 |
| IP International Paper Co. | Sold out | 0.00% | −0.46 |
| MSFT Microsoft Corp. | Reduce -4.9% | 3.27% | −0.44 |
| GKOS Glaukos Corp. | Sold out | 0.00% | −0.42 |
| COST Costco Wholesale Corp. | Sold out | 0.00% | −0.36 |
| PLTR Palantir Technologies Inc. Class A | Reduce -74.5% | 0.11% | −0.35 |
| ORCL Oracle Corp. | Reduce -21.0% | 0.39% | −0.32 |
| PRCT Procept Biorobotics Corp. | Sold out | 0.00% | −0.29 |
| ICLR Icon PLC | Reduce -99.4% | 0.00% | −0.29 |
| FIX Comfort Systems USA Inc. | Reduce -19.7% | 2.60% | −0.28 |
| RH RH | Sold out | 0.00% | −0.28 |
| PINS Pinterest Inc. Class A | Sold out | 0.00% | −0.27 |
| VEEV Veeva Systems Inc. Class A | Sold out | 0.00% | −0.27 |
| ICE Intercontinental Exchange Inc. | Sold out | 0.00% | −0.27 |
| SMTC Semtech Corp. | Reduce -27.6% | 0.75% | −0.26 |
| SLNO Soleno Therapeutics Inc. | Sold out | 0.00% | −0.26 |
| DXCM Dexcom Inc. | Reduce -37.7% | 0.40% | −0.25 |
| KNSL Kinsale Capital Group Inc. | Sold out | 0.00% | −0.25 |
| TWLO Twilio Inc. Class A | Sold out | 0.00% | −0.25 |
| SPOT Spotify Technology SA | Sold out | 0.00% | −0.25 |
| TTMI TTM Technologies | Sold out | 0.00% | −0.24 |
| MRVL Marvell Technology Inc. | Reduce -25.4% | 0.69% | −0.23 |
| EAT Brinker International Inc. | Sold out | 0.00% | −0.22 |
| SN Sharkninja Inc. | Reduce -40.1% | 0.39% | −0.22 |
| RRX Regal Rexnord Corp. | Reduce -26.9% | 0.52% | −0.21 |
| FOUR SHIFT4 Payments Inc. Class A | Sold out | 0.00% | −0.21 |
| ETNB 89BIO Inc. | Sold out | 0.00% | −0.20 |
| GEV GE Vernova Inc. | Reduce -33.0% | 0.48% | −0.20 |
| NOG Northern Oil and Gas Inc. | Sold out | 0.00% | −0.20 |
| P Everpure Inc. Class A | Reduce -13.2% | 0.42% | −0.19 |
| WSC Willscot Holdings Corp. | Sold out | 0.00% | −0.18 |
| BE Bloom Energy Corp. Class A | Reduce -31.6% | 0.41% | −0.18 |
| ENTG Entegris Inc. | Sold out | 0.00% | −0.18 |
| KRMN Karman Holdings Inc. | Reduce -41.3% | 0.26% | −0.18 |
| KD Kyndryl Holdings Inc. | Sold out | 0.00% | −0.17 |
| COHR Coherent Corp. | Reduce -54.8% | 0.51% | −0.15 |
| PCOR Procore Technologies Inc. | Reduce -28.2% | 0.33% | −0.14 |
| V Visa Inc. Class A | Reduce -14.4% | 0.88% | −0.13 |
| RYAN Ryan Specialty Holdings Inc. | Reduce -36.3% | 0.18% | −0.13 |
| BWIN Baldwin Insurance Group Inc./ | Sold out | 0.00% | −0.13 |
| BLDR Builders Firstsource Inc. | Reduce -22.8% | 0.20% | −0.11 |
| RIOT Riot Platforms Inc. | Sold out | 0.00% | −0.11 |
| AMZN Amazon.com Inc. | Reduce -8.3% | 2.24% | −0.10 |
| BIRK Birkenstock Holding PLC | Reduce -13.3% | 0.33% | −0.10 |
Portfolio Buys Q3 2025 → Q4 2025
| ABVX Abivax SA-ADR | New | 0.57% | +0.57 |
| APG Api Group Corp. | New | 0.55% | +0.55 |
| AME Ametek Inc. | Add +151.0% | 0.77% | +0.49 |
| BROS Dutch Bros Inc. Class A | New | 0.45% | +0.45 |
| RVMD Revolution Medicines Inc. | Add +13.2% | 0.94% | +0.45 |
| FTAI Ftai Aviation Ltd. | Add +10.3% | 1.93% | +0.44 |
| FITB Fifth Third Bancorp | Add +131.3% | 0.73% | +0.43 |
| ABBV Abbvie Inc. | Add +5194.9% | 0.40% | +0.39 |
| MKSI MKS Inc. | Add +159.7% | 0.56% | +0.39 |
| LLY Eli Lilly & Co. | Add +0.2% | 1.24% | +0.36 |
| TEAM Atlassian Corp. Class A | Add +151.9% | 0.55% | +0.33 |
| HUBS HubSpot Inc. | Add +162.5% | 0.59% | +0.33 |
| WGS Genedx Holdings Corp. | Add +87.2% | 0.55% | +0.31 |
| DHR Danaher Corp. | Add +6390.8% | 0.31% | +0.30 |
| CELH Celsius Holdings Inc. | New | 0.29% | +0.29 |
| NTRA Natera Inc. | Add +24.1% | 0.68% | +0.29 |
| LGN Legence Corp. Class A | New | 0.29% | +0.29 |
| GRMN Garmin Ltd. | New | 0.28% | +0.28 |
| FFIV F5 Inc. | Add +1634.3% | 0.30% | +0.28 |
| ADPT Adaptive Biotechnologies | New | 0.27% | +0.27 |
| RKLB Rocket Lab Corp. | Add +6.3% | 0.75% | +0.26 |
| ZS Zscaler Inc. | New | 0.26% | +0.26 |
| MCO Moody's Corp. | New | 0.25% | +0.25 |
| PKG Packaging Corp. of America | New | 0.24% | +0.24 |
| TECH Bio-Techne Corp. | New | 0.24% | +0.24 |
| HWM Howmet Aerospace Inc. | Add +10.5% | 1.90% | +0.24 |
| DORM Dorman Products Inc. | New | 0.24% | +0.24 |
| GH Guardant Health Inc. | New | 0.23% | +0.23 |
| AMD Advanced Micro Devices | New | 0.22% | +0.22 |
| ADMA Adma Biologics Inc. | Add +36.9% | 0.53% | +0.22 |
| HLNE Hamilton Lane Inc. Class A | New | 0.20% | +0.20 |
| CRM Salesforce Inc. | New | 0.20% | +0.20 |
| PODD Insulet Corp. | Add +91.9% | 0.46% | +0.20 |
| PH Parker Hannifin Corp. | Add +706.9% | 0.21% | +0.19 |
| HLT Hilton Worldwide Holdings Inc. | Add +53.1% | 0.43% | +0.17 |
| PR Permian Resources Corp. Class A | Add +77.2% | 0.35% | +0.17 |
| TT Trane Technologies PLC | Add +642.4% | 0.19% | +0.16 |
| IDXX Idexx Laboratories Inc. | Add +56.6% | 0.42% | +0.16 |
| EWBC East West Bancorp Inc. | Add +48.3% | 0.41% | +0.15 |
| BURL Burlington Stores Inc. | Add +46.8% | 0.36% | +0.14 |
| RNAM Avidity Biosciences Inc. | New | 0.14% | +0.14 |
| IMAX Imax Corp. | Add +44.6% | 0.36% | +0.14 |
| LPLA LPL Financial Holdings Inc. | Add +8.7% | 0.93% | +0.13 |
| FTI Technipfmc PLC | Add +31.9% | 0.36% | +0.12 |
| VRT Vertiv Holdings Co. Class A | Add +1.4% | 1.54% | +0.11 |
| IONQ Ionq Inc. | Add +203.2% | 0.21% | +0.11 |
| RYTM Rhythm Pharmaceuticals Inc. | Add +18.5% | 0.56% | +0.11 |
| FN Fabrinet | Add +16.7% | 0.36% | +0.11 |
| TSLA Tesla Inc. | Add +14.2% | 0.86% | +0.11 |
| FICO Fair Isaac Corp. | Add +37.3% | 0.31% | +0.11 |
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 |