Westfield Capital Management CO LP
BOSTON, MA
$30.6bn in 278 US stocks at the end of 30 June 2026. The top 10 are 29.2% of the money. It changed about 29.7% of the portfolio this quarter.
Value
$30.6bn
Stocks
278
Top 10 share
29.2%
Turnover
29.7%
What changed this quarter
New
Bought for the first time this quarter.
- Ascendis Pharma A/SASND4.2% of the fund
- Carpenter TechnologyCRS0.6% of the fund
- PTC TherapeuticsPTCT0.5% of the fund
- Lam ResearchLRCX0.4% of the fund
- ASML Holding NVASML0.4% of the fund
- SandiskSNDK0.4% of the fund
- EnproNPO0.4% of the fund
- JFrogFROG0.3% of the fund
- TTM TechnologiesTTMI0.3% of the fund
- Forgent Power SolutionsFPS0.3% of the fund
- RubrikRBRK0.2% of the fund
- Sprouts Farmers MarketSFM0.2% of the fund
- Nuvalent0.2% of the fund
- Dycom IndustriesDY0.2% of the fund
- TeradyneTER0.2% of the fund
- Sensata Technologies HoldingST0.2% of the fund
- BrightSpring Health ServicesBTSG0.2% of the fund
- Relay TherapeuticsRLAY0.2% of the fund
- Builders FirstSourceBLDR0.2% of the fund
- RobloxRBLX0.2% of the fund
- Argenx SEARGX0.2% of the fund
- FlexFLEX0.2% of the fund
- Spotify TechnologySPOT0.2% of the fund
- Analog DevicesADI0.2% of the fund
- NasdaqNDAQ0.2% of the fund
Added
Bought more of a stock they already held.
- NvidiaNVDA5.3% of the fund+28%
- AlphabetGOOGL4.4% of the fund+85%
- Axon EnterpriseAXON2.7% of the fund+40%
- FTAI AviationFTAI2.6% of the fund+3%
- BroadcomAVGO1.9% of the fund+26%
- Eli LillyLLY1.6% of the fund+14%
- SnowflakeSNOW1.4% of the fund+142%
- Meta PlatformsMETA1.2% of the fund+29%
- GE VernovaGEV0.9% of the fund+21%
- Micron TechnologyMU0.9% of the fund+127%
- VisaV0.9% of the fund+67%
- APi GroupAPG0.9% of the fund+33%
- Rhythm PharmaceuticalsRYTM0.8% of the fund+14%
- Life Time Group HoldingsLTH0.8% of the fund+88%
- Taiwan Semiconductor ManufacturingTSM0.8% of the fund+4%
- Guardant HealthGH0.8% of the fund+19%
- ServiceNowNOW0.8% of the fund+70%
- Advanced Micro DevicesAMD0.8% of the fund+7930%
- Palo Alto NetworksPANW0.7% of the fund+3%
- WoodwardWWD0.7% of the fund+93%
- Arista NetworksANET0.7% of the fund+69%
- Amer SportsAS0.7% of the fund+61%
- CloudflareNET0.7% of the fund+54%
- GarminGRMN0.7% of the fund+129%
- Regal RexnordRRX0.7% of the fund+26%
Cut
Sold some of their stake.
- AppleAAPL2.4% of the fund-18%
- Comfort Systems USAFIX2.3% of the fund-43%
- MicrosoftMSFT1.7% of the fund-14%
- Howmet AerospaceHWM1.7% of the fund-16%
- MKSMKSI1.3% of the fund-11%
- Vertiv HoldingsVRT1.2% of the fund-45%
- TapestryTPR0.8% of the fund-23%
- LPL Financial HoldingsLPLA0.7% of the fund-10%
- Rocket LabRKLB0.7% of the fund-33%
- Amazon.comAMZN0.7% of the fund-62%
- NateraNTRA0.6% of the fund-4%
- SemtechSMTC0.6% of the fund-12%
- AmetekAME0.6% of the fund-3%
- Dutch BrosBROS0.5% of the fund-6%
- VaxcytePCVX0.5% of the fund-32%
- Globe LifeGL0.4% of the fund-8%
- Legend BiotechLEGN0.4% of the fund-23%
- EverpureP0.4% of the fund-14%
- Astera LabsALAB0.4% of the fund-71%
- CoherentCOHR0.4% of the fund-27%
- LegenceLGN0.4% of the fund-28%
- Onto InnovationONTO0.4% of the fund-8%
- CencoraCOR0.4% of the fund-8%
- Revolution MedicinesRVMD0.4% of the fund-61%
- Live Nation EntertainmentLYV0.4% of the fund-27%
Sold out
Sold their entire stake.
- Ascendis Pharma A/SASND-100%
- Kratos Defense & Security SolutionsKTOS-100%
- American International GroupAIG-100%
- Palantir TechnologiesPLTR-100%
- GeneDx HoldingsWGS-100%
- F5FFIV-100%
- C. H. Robinson WorldwideCHRW-100%
- Lowe's CompaniesLOW-100%
- Masimo-100%
- ZscalerZS-100%
- HubspotHUBS-100%
- Installed Building ProductsIBP-100%
- Moody'sMCO-100%
- Topbuild COR-100%
- KKRKKR-100%
- Bio-TechneTECH-100%
- Fair IsaacFICO-100%
- IonQIONQ-100%
- Hamilton LaneHLNE-100%
- Option Care HealthOPCH-100%
- TransDigm GroupTDG-100%
- Wells Fargo & CompanyWFC-100%
- M&T BankMTB-100%
- Raymond James FinancialRJF-100%
- McDonald'sMCD-100%
Holdings
- Abivax SAABVX
- Share
- 0.6%
- Value
- $175m
- Shares
- 1,309,825
Held
- Legend BiotechLEGN
- Share
- 0.4%
- Value
- $128m
- Shares
- 4,430,063
-23%
| Company | Share of fund | Value | Shares | Change |
|---|---|---|---|---|
| NvidiaNVDA | 5.3% | $1.6bn | 8,079,926 | +28% |
| AlphabetGOOGL | 4.4% | $1.3bn | 3,749,074 | +85% |
| Ascendis Pharma A/SASND | 4.2% | $1.3bn | 4,798,267 | New |
| Axon EnterpriseAXON | 2.7% | $836m | 1,491,490 | +40% |
| FTAI AviationFTAI | 2.6% | $795m | 2,937,228 | +3% |
| AppleAAPL | 2.4% | $745m | 2,573,774 | -18% |
| Comfort Systems USAFIX | 2.3% | $704m | 355,433 | -43% |
| BroadcomAVGO | 1.9% | $588m | 1,556,522 | +26% |
| MicrosoftMSFT | 1.7% | $528m | 1,414,294 | -14% |
| Howmet AerospaceHWM | 1.7% | $517m | 1,921,476 | -16% |
| Eli LillyLLY | 1.6% | $500m | 416,732 | +14% |
| SnowflakeSNOW | 1.4% | $442m | 1,736,498 | +142% |
| MKSMKSI | 1.3% | $413m | 928,617 | -11% |
| Meta PlatformsMETA | 1.2% | $382m | 677,389 | +29% |
| Vertiv HoldingsVRT | 1.2% | $353m | 1,054,361 | -45% |
| GE VernovaGEV | 0.9% | $283m | 241,272 | +21% |
| Micron TechnologyMU | 0.9% | $263m | 228,203 | +127% |
| VisaV | 0.9% | $262m | 762,403 | +67% |
| APi GroupAPG | 0.9% | $261m | 6,154,301 | +33% |
| TapestryTPR | 0.8% | $248m | 1,696,569 | -23% |
| Rhythm PharmaceuticalsRYTM | 0.8% | $245m | 2,208,595 | +14% |
| Life Time Group HoldingsLTH | 0.8% | $245m | 5,995,254 | +88% |
| Taiwan Semiconductor ManufacturingTSM | 0.8% | $244m | 510,999 | +4% |
| Guardant HealthGH | 0.8% | $244m | 1,624,459 | +19% |
| Quanta ServicesPWR | 0.8% | $239m | 331,489 | Held |
| ServiceNowNOW | 0.8% | $236m | 2,373,711 | +70% |
| Advanced Micro DevicesAMD | 0.8% | $234m | 403,081 | +7930% |
| Palo Alto NetworksPANW | 0.7% | $225m | 658,331 | +3% |
| WoodwardWWD | 0.7% | $224m | 526,505 | +93% |
| Arista NetworksANET | 0.7% | $224m | 1,317,096 | +69% |
| LPL Financial HoldingsLPLA | 0.7% | $223m | 793,061 | -10% |
| Rocket LabRKLB | 0.7% | $215m | 2,114,005 | -33% |
| Amer SportsAS | 0.7% | $215m | 6,344,923 | +61% |
| CloudflareNET | 0.7% | $205m | 835,502 | +54% |
| Amazon.comAMZN | 0.7% | $205m | 859,806 | -62% |
| GarminGRMN | 0.7% | $205m | 861,057 | +129% |
| Regal RexnordRRX | 0.7% | $204m | 856,976 | +26% |
| NateraNTRA | 0.6% | $197m | 726,628 | -4% |
| Morgan StanleyMS | 0.6% | $197m | 940,560 | +89% |
| Carpenter TechnologyCRS | 0.6% | $194m | 314,082 | New |
| SamsaraIOT | 0.6% | $189m | 5,836,459 | +15% |
| DynatraceDT | 0.6% | $187m | 4,249,229 | Held |
| CaterpillarCAT | 0.6% | $186m | 174,620 | +440% |
| SemtechSMTC | 0.6% | $183m | 1,133,268 | -12% |
| AmetekAME | 0.6% | $175m | 723,798 | -3% |
| Abivax SAABVX | 0.6% | $175m | 1,309,825 | Held |
| InsmedINSM | 0.6% | $174m | 1,629,561 | +11% |
| ITTITT | 0.5% | $164m | 830,382 | +18% |
| Gilead SciencesGILD | 0.5% | $163m | 1,287,629 | +4724% |
| PTC TherapeuticsPTCT | 0.5% | $160m | 1,956,156 | New |
| Dutch BrosBROS | 0.5% | $157m | 2,184,001 | -6% |
| Celsius HoldingsCELH | 0.5% | $156m | 5,324,481 | +41% |
| MastecMTZ | 0.5% | $156m | 374,457 | +50% |
| SharkNinjaSN | 0.5% | $154m | 1,008,349 | +11% |
| CSXCSX | 0.5% | $150m | 3,154,419 | +90% |
| FirstCash HoldingsFCFS | 0.5% | $150m | 693,085 | +60% |
| KeycorpKEY | 0.5% | $150m | 6,493,467 | +25% |
| Microchip TechnologyMCHP | 0.5% | $149m | 1,639,111 | +69% |
| Applied MaterialsAMAT | 0.5% | $149m | 205,592 | +21865% |
| Marriott InternationalMAR | 0.5% | $148m | 398,962 | +160% |
| VaxcytePCVX | 0.5% | $144m | 2,472,428 | -32% |
| Globe LifeGL | 0.4% | $138m | 770,990 | -8% |
| TechnipFMCFTI | 0.4% | $137m | 2,059,689 | Held |
| XPOXPO | 0.4% | $129m | 629,011 | +10% |
| Legend BiotechLEGN | 0.4% | $128m | 4,430,063 | -23% |
| EverpureP | 0.4% | $127m | 1,611,958 | -14% |
| Lam ResearchLRCX | 0.4% | $124m | 285,614 | New |
| Jones Lang LasalleJLL | 0.4% | $124m | 398,453 | +15% |
| Astera LabsALAB | 0.4% | $120m | 249,299 | -71% |
| Rockwell AutomationROK | 0.4% | $117m | 237,136 | +15% |
| IdexIEX | 0.4% | $117m | 513,564 | +21% |
| CoherentCOHR | 0.4% | $115m | 291,040 | -27% |
| LegenceLGN | 0.4% | $114m | 1,341,963 | -28% |
| Lincoln Electric HoldingsLECO | 0.4% | $114m | 430,681 | +20% |
| ASML Holding NVASML | 0.4% | $114m | 57,430 | New |
| Planet Labs PBCPL | 0.4% | $114m | 3,428,007 | +109% |
| Onto InnovationONTO | 0.4% | $113m | 299,383 | -8% |
| CencoraCOR | 0.4% | $113m | 400,058 | -8% |
| Revolution MedicinesRVMD | 0.4% | $113m | 600,821 | -61% |
| SandiskSNDK | 0.4% | $111m | 49,024 | New |
| Affirm HoldingsAFRM | 0.4% | $110m | 1,352,200 | +25% |
| Live Nation EntertainmentLYV | 0.4% | $108m | 590,764 | -27% |
| EnproNPO | 0.4% | $108m | 286,554 | New |
| Permian ResourcesPR | 0.3% | $106m | 5,756,888 | -23% |
| Ares ManagementARES | 0.3% | $106m | 952,032 | -39% |
| ImaxIMAX | 0.3% | $106m | 2,654,014 | +13% |
| Guidewire SoftwareGWRE | 0.3% | $103m | 839,337 | +73% |
| NextpowerNXT | 0.3% | $102m | 857,399 | -23% |
| JFrogFROG | 0.3% | $101m | 1,114,561 | New |
| SynopsysSNPS | 0.3% | $101m | 226,856 | +71% |
| RokuROKU | 0.3% | $99m | 716,557 | -39% |
| PlexusPLXS | 0.3% | $97m | 321,808 | -16% |
| Applied Industrial TechnologiesAIT | 0.3% | $97m | 285,691 | Held |
| MsciMSCI | 0.3% | $96m | 171,958 | -26% |
| Robinhood MarketsHOOD | 0.3% | $96m | 955,544 | +51% |
| Ross StoresROST | 0.3% | $94m | 442,420 | -6% |
| Adaptive BiotechnologiesADPT | 0.3% | $92m | 4,267,645 | -22% |
| Xenon PharmaceuticalsXENE | 0.3% | $91m | 1,507,294 | +8% |
| O'Reilly AutomotiveORLY | 0.3% | $86m | 933,255 | +5% |
| CitigroupC | 0.3% | $85m | 608,124 | +1268% |
Showing the largest 100 of 278.
Over time and by industry
Value over time
Jun '25
Dec '25
Jun '26
Value is up 28.4% since 30 June 2025.
Where the money is
Technology34.4%
Industrials21.0%
Health care15.0%
Retail & consumer8.2%
Financial services8.0%
Media & telecom6.8%
Energy1.4%
Materials1.3%
Everyday goods1.1%
Utilities0.8%
Real estate0.5%
Other1.6%
From the fund's 13F filings. They list US stocks and options only, 45 days after each quarter, and leave out cash, bonds, shorts and foreign shares.