Westfield Capital Management Co LP holds a diversified book of 250 stocks worth $23.8B as of Q1 2026 (disclosed May 11, 2026, a ~45-day 13F lag). This quarter they opened Cheniere Energy Inc and trimmed Ascendis Pharma A/s. Their largest long position is Nvidia Corp at 5% of the equity book.
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curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://arkolith.com/api/v1/funds/1177719/holdings"
Use Arkolith to show WESTFIELD CAPITAL MANAGEMENT CO LP's latest holdings, largest changes, and filing provenance.
Top-heavy: diversified book
Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.
95% mapped to company sectors
Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.
Estimated $ traded · quarter-end prices, no cost basis
Bars show each stock's share of the portfolio. Click a row for its position history.
| # | Security | Value | Shares | % Port | Last move | History |
|---|---|---|---|---|---|---|
| 1 | Nvidia Corporation COM | $1.1B | 6.32M | 4.6% | ▲+6.2% Added · +366K sh | |
| 2 | Ascendis Pharma A/s SPONSORED ADR | $1.1B | 4.81M | 4.6% | ▼−7.2% Reduced · −372K sh | |
| 3 | Comfort Sys USA Inc COM | $856.2M | 620.9K | 3.6% | ▼−7.2% Reduced · −48K sh | |
| 4 | Apple Inc COM | $795.2M | 3.13M | 3.3% | ▼−4.3% Reduced · −141K sh | |
| 5 | Ftai Aviation Ltd SHS | $697.8M | 2.85M | 2.9% | ▲+21% Added · +498K sh | |
| 6 | Microsoft Corp COM | $610.6M | 1.65M | 2.6% | ▲+1.7% Added · +28K sh | |
| 7 | Alphabet Inc CAP STK CL A | $582.8M | 2.03M | 2.4% | ▼−7.0% Reduced · −152K sh | |
| 8 | Howmet Aerospace Inc COM | $527.7M | 2.29M | 2.2% | ▲+3.2% Added · +71K sh | |
| 9 | Vertiv Holdings Co COM CL A | $481.5M | 1.92M | 2.0% | ▼−16% Reduced · −356K sh | |
| 10 | Amazon Com Inc COM | $474.8M | 2.28M | 2.0% | ▼−2.2% Reduced · −51K sh | |
| 11 | Axon Enterprise Inc COM | $451.9M | 1.06M | 1.9% | ▲+28% Added · +233K sh | |
| 12 | Broadcom Inc COM | $382.8M | 1.24M | 1.6% | ▲+11% Added · +125K sh | |
| 13 | Eli Lilly & Co COM | $335.3M | 364.6K | 1.4% | ▲+31% Added · +87K sh | |
| 14 | Tapestry Inc COM | $310.3M | 2.20M | 1.3% | ▲+4.8% Added · +101K sh | |
| 15 | Meta Platforms Inc CL A | $301.4M | 526.8K | 1.3% | ▼−20% Reduced · −128K sh | |
| 16 | LPL Finl Hldgs Inc COM | $265.2M | 881.5K | 1.1% | ▲+41% Added · +256K sh | |
| 17 | MKS Inc. COM | $240.6M | 1.05M | 1.0% | ▲+25% Added · +207K sh | |
| 18 | Insmed Inc COM PAR $.01 | $240.1M | 1.47M | 1.0% | ▲+240% Added · +1.0M sh | |
| 19 | Vaxcyte Inc COM | $211.9M | 3.65M | 0.9% | ▲+3.0% Added · +106K sh | |
| 20 | Rocket Lab Corp COM | $203.7M | 3.17M | 0.9% | ▲+22% Added · +580K sh | |
| 21 | Netflix Inc. COM | $189.4M | 1.97M | 0.8% | ▲+23% Added · +372K sh | |
| 22 | Api Group Corp COM STK | $187.8M | 4.63M | 0.8% | ▲+34% Added · +1.2M sh | |
| 23 | Quanta Svcs Inc COM | $182.2M | 331.8K | 0.8% | ▲+21% Added · +58K sh | |
| 24 | Ge Vernova Inc COM | $174.0M | 199.3K | 0.7% | ▲+12% Added · +21K sh | |
| 25 | Ares Management Corporation CL A COM STK | $171.6M | 1.57M | 0.7% | ▲+37% Added · +422K sh | |
| 26 | Rhythm Pharmaceuticals Inc COM | $167.8M | 1.93M | 0.7% | ▲+52% Added · +662K sh | |
| 27 | Taiwan Semiconductor Manufac SPONSORED ADS | $166.8M | 493.5K | 0.7% | ▲+11% Added · +47K sh | |
| 28 | Marvell Technology Inc COM | $165.7M | 1.67M | 0.7% | ▼−14% Reduced · −274K sh | |
| 29 | Bloom Energy Corp COM CL A | $161.4M | 1.19M | 0.7% | ▲+4.0% Added · +46K sh | |
| 30 | Samsara Inc COM CL A | $160.8M | 5.07M | 0.7% | ▲+28% Added · +1.1M sh | |
| 31 | Ametek Inc COM | $159.9M | 745.8K | 0.7% | ▼−17% Reduced · −154K sh | |
| 32 | Permian Resources Corp CLASS A COM | $159.5M | 7.48M | 0.7% | ▲+26% Added · +1.5M sh | |
| 33 | Dynatrace Inc COM NEW | $155.7M | 4.21M | 0.7% | ▲+25% Added · +853K sh | |
| 34 | Revolution Medicines Inc COM | $151.4M | 1.56M | 0.6% | ▼−45% Reduced · −1.3M sh | |
| 35 | Natera Inc COM | $150.9M | 754.7K | 0.6% | ▲+5.6% Added · +40K sh | |
| 36 | Fabrinet SHS | $148.6M | 284.9K | 0.6% | ▲+50% Added · +95K sh | |
| 37 | Abivax Sa SPONSORED ADS | $147.3M | 1.32M | 0.6% | ▲+31% Added · +313K sh | |
| 38 | Servicenow Inc COM | $145.8M | 1.39M | 0.6% | ▼−5.6% Reduced · −83K sh | |
| 39 | Technipfmc PLC COM | $140.6M | 2.03M | 0.6% | ▲+4.2% Added · +81K sh | |
| 40 | Royal Caribbean Group COM | $139.2M | 505.8K | 0.6% | ▲+13% Added · +57K sh | |
| 41 | Hilton Worldwide Hldgs Inc COM | $139.1M | 457.4K | 0.6% | ▲+28% Added · +100K sh | |
| 42 | Visa Inc COM CL A | $138.0M | 456.5K | 0.6% | ▼−24% Reduced · −147K sh | |
| 43 | Cencora Inc COM | $137.3M | 436.9K | 0.6% | ▲+37% Added · +118K sh | |
| 44 | Itt Inc COM | $134.0M | 703.3K | 0.6% | ▲+20% Added · +116K sh | |
| 45 | Celsius Hldgs Inc COM NEW | $133.7M | 3.77M | 0.6% | ▲+144% Added · +2.2M sh | |
| 46 | Nextpower Inc CLASS A COM | $133.5M | 1.11M | 0.6% | ▲+1.6% Added · +17K sh | |
| 47 | Cheniere Energy Inc COM NEW | $130.3M | 459.0K | 0.5% | ▲New New position | |
| 48 | Amer Sports Inc COM SHS | $129.6M | 3.94M | 0.5% | ▲New New position | |
| 49 | Regal Rexnord Corporation COM | $127.7M | 681.7K | 0.5% | ▼−24% Reduced · −211K sh | |
| 50 | Msci Inc COM | $126.0M | 233.8K | 0.5% | ▲+12% Added · +26K sh |
As-of date vs the date the SEC received each filing
| Quarter | As of | Filed | Positions | Value | Form |
|---|---|---|---|---|---|
| Q1 2026 | Mar 31, 2026 | May 11, 2026 | 250 | $23.8B | 13F-HR |
| Q4 2025 | Dec 31, 2025 | Feb 11, 2026 | 241 | $24.0B | 13F-HR |
| Q3 2025 | Sep 30, 2025 | Nov 12, 2025 | 235 | $23.8B | 13F-HR |
| Q2 2025 | Jun 30, 2025 | Aug 12, 2025 | 239 | $23.8B | 13F-HR |
| Q1 2025 | Mar 31, 2025 | May 9, 2025 | 244 | $20.5B | 13F-HR |
| Q4 2024 | Dec 31, 2024 | Feb 11, 2025 | 239 | $23.0B | 13F-HR |
| Q3 2024 | Sep 30, 2024 | Nov 12, 2024 | 247 | $22.1B | 13F-HR |
| Q2 2024 | Jun 30, 2024 | Aug 14, 2024 | 248 | $20.4B | 13F-HR |
| Q1 2024 | Mar 31, 2024 | May 10, 2024 | 244 | $19.0B | 13F-HR |
| Q4 2023 | Dec 31, 2023 | Feb 9, 2024 | 239 | $17.2B | 13F-HR |
| Q3 2023 | Sep 30, 2023 | Nov 13, 2023 | 234 | $14.7B | 13F-HR |
| Q2 2023 | Jun 30, 2023 | Aug 11, 2023 | 227 | $15.7B | 13F-HR |
| Q1 2023 | Mar 31, 2023 | May 12, 2023 | 222 | $14.2B | 13F-HR |
| Q4 2022 | Dec 31, 2022 | Feb 13, 2023 | 226 | $13.0B | 13F-HR |
| Q3 2022 | Sep 30, 2022 | Nov 14, 2022 | 230 | $12.6B | 13F-HR |
| Q2 2022 | Jun 30, 2022 | Aug 12, 2022 | 235 | $12.7B | 13F-HR |
| Q1 2022 | Mar 31, 2022 | May 16, 2022 | 235 | $15.6B | 13F-HR |
| Q4 2021 | Dec 31, 2021 | Feb 10, 2022 | 244 | $16.8B | 13F-HR |
| Q3 2021 | Sep 30, 2021 | Nov 12, 2021 | 235 | $16.6B | 13F-HR |
| Q2 2021 | Jun 30, 2021 | Aug 10, 2021 | 241 | $16.7B | 13F-HR |
| Q1 2021 | Mar 31, 2021 | May 14, 2021 | 243 | $16.1B | 13F-HR |
| Q4 2020 | Dec 31, 2020 | Feb 12, 2021 | 247 | $16.9B | 13F-HR |
| Q3 2020 | Sep 30, 2020 | Nov 13, 2020 | 235 | $15.4B | 13F-HR |
| Q2 2020 | Jun 30, 2020 | Aug 13, 2020 | 230 | $14.5B | 13F-HR |
Holdings from SEC EDGAR 13F-HR filings, updated quarterly ~45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.