WESTFIELD CAPITAL MANAGEMENT CO LP
13F filer · CIK 1177719 · Boston, MA
Summary
WESTFIELD CAPITAL MANAGEMENT CO LP reported $30.61B across 278 positions in its 13F for 2026 Q2, filed Aug 12, 2026. The largest holdings are NVDA (5.3%), GOOGL (4.4%), ASND (4.2%). Versus 2026 Q1, leaving options aside, it opened 69 new positions, added to 98, trimmed 103 and sold out of 41.
Reported value$30.61B
Positions278
Report period2026 Q2
FiledAug 12, 2026
New positions69
Added98
Trimmed103
Sold out41
Top 25 holdings
By reported value, options listed separately · change vs 2026 Q1
Weight 5.3%Value $1.62BPrice $227.21Shares 8.08M +27.91%Since Jun 30 +13.55%
Weight 4.4%Value $1.34BPrice $340.92Shares 3.75M +84.98%Since Jun 30 -4.60%
Weight 4.2%Value $1.28BPrice $228.07Shares 4.80MSince Jun 30 -14.49%
Weight 2.7%Value $836.14MPrice $419.58Shares 1.49M +40.16%Since Jun 30 -25.16%
Weight 2.6%Value $794.61MPrice $168.93Shares 2.94M +3.12%Since Jun 30 -37.56%
Weight 2.4%Value $744.75MPrice $329.40Shares 2.57M -17.85%Since Jun 30 +13.84%
Weight 2.3%Value $704.45MPrice $1665Shares 355K -42.76%Since Jun 30 -15.99%
Weight 1.9%Value $587.98MPrice $355.10Shares 1.56M +25.84%Since Jun 30 -6.00%
Weight 1.7%Value $527.56MPrice $508.96Shares 1.41M -14.26%Since Jun 30 +36.44%
Weight 1.7%Value $516.61MPrice $230.94Shares 1.92M -16.08%Since Jun 30 -14.10%
Weight 1.6%Value $499.84MPrice $1185Shares 417K +14.30%Since Jun 30 -1.23%
Weight 1.4%Value $441.94MPrice $330.31Shares 1.74M +141.58%Since Jun 30 +29.79%
Weight 1.3%Value $413.05MPrice $266.02Shares 929K -11.29%Since Jun 30 -40.19%
Weight 1.2%Value $381.57MPrice $738.79Shares 677K +28.58%Since Jun 30 +31.16%
Weight 1.2%Value $353.02MPrice $248.34Shares 1.05M -45.13%Since Jun 30 -25.83%
Weight 0.9%Value $283.46MPrice $962.49Shares 241K +21.06%Since Jun 30 -18.08%
Weight 0.9%Value $263.41MPrice $1065Shares 228K +127.22%Since Jun 30 -7.73%
Weight 0.9%Value $261.57MPrice $365.88Shares 762K +66.99%Since Jun 30 +6.64%
Weight 0.9%Value $260.63MPrice $38.75Shares 6.15M +32.78%Since Jun 30 -8.50%
Weight 0.8%Value $248.34MPrice $114.12Shares 1.70M -22.84%Since Jun 30 -22.04%
Weight 0.8%Value $245.22MPrice $95.71Shares 2.21M +14.49%Since Jun 30 -13.80%
Weight 0.8%Value $244.85MPrice $40.08Shares 6.00M +88.20%Since Jun 30 -1.86%
Weight 0.8%Value $244.04MPrice $456.94Shares 511K +3.55%Since Jun 30 -4.32%
Weight 0.8%Value $243.72MPrice $177.73Shares 1.62M +19.22%Since Jun 30 +18.46%
Weight 0.8%Value $238.69MPrice $651.79Shares 331K -0.10%Since Jun 30 -9.48%
| Stock | Weight | Value | Since Jun 30 | Shares change | Action |
|---|---|---|---|---|---|
| 5.3% | $1.62B | +13.55% | +27.91% | Add | |
| 4.4% | $1.34B | -4.60% | +84.98% | Add | |
| 4.2% | $1.28B | -14.49% | — | New | |
| 2.7% | $836.14M | -25.16% | +40.16% | Add | |
| 2.6% | $794.61M | -37.56% | +3.12% | Add | |
| 2.4% | $744.75M | +13.84% | -17.85% | Trim | |
| 2.3% | $704.45M | -15.99% | -42.76% | Trim | |
| 1.9% | $587.98M | -6.00% | +25.84% | Add | |
| 1.7% | $527.56M | +36.44% | -14.26% | Trim | |
| 1.7% | $516.61M | -14.10% | -16.08% | Trim | |
| 1.6% | $499.84M | -1.23% | +14.30% | Add | |
| 1.4% | $441.94M | +29.79% | +141.58% | Add | |
| 1.3% | $413.05M | -40.19% | -11.29% | Trim | |
| 1.2% | $381.57M | +31.16% | +28.58% | Add | |
| 1.2% | $353.02M | -25.83% | -45.13% | Trim | |
| 0.9% | $283.46M | -18.08% | +21.06% | Add | |
| 0.9% | $263.41M | -7.73% | +127.22% | Add | |
| 0.9% | $261.57M | +6.64% | +66.99% | Add | |
| 0.9% | $260.63M | -8.50% | +32.78% | Add | |
| 0.8% | $248.34M | -22.04% | -22.84% | Trim | |
| 0.8% | $245.22M | -13.80% | +14.49% | Add | |
| 0.8% | $244.85M | -1.86% | +88.20% | Add | |
| 0.8% | $244.04M | -4.32% | +3.55% | Add | |
| 0.8% | $243.72M | +18.46% | +19.22% | Add | |
| 0.8% | $238.69M | -9.48% | -0.10% | Trim |
Weight is the share of the reported 13F value, including options at notional value. “Since Jun 30” compares the latest close with the quarter-end price implied by the filing (value ÷ shares).
Largest buys in 2026 Q2
Largest sells in 2026 Q2
Source: SEC Form 13F, values as reported by the filer. Filings lag up to 45 days after quarter end and cover only certain long positions. Research only, not investment advice.