Filed: 8/12/2026ACC: 0001177719-26-000021
📋 What this filing means
WESTFIELD CAPITAL MANAGEMENT CO LP filed this quarterly 13F‑HR report disclosing 278 equity positions with a total reported market value of $30.61B. This filing provides a transparent view of the manager's long equity holdings as of the quarter end.
278
Positions
$30.61B
Total AUM (reported)
236.91M
Total Shares
Allocation by class
COM$19.19B62.7%
CL A$1.46B4.8%
ORD SHS$1.43B4.7%
COM CL A$1.36B4.4%
CAP STK CL A$1.34B4.4%
SHS$1.18B3.8%
COM SHS$1.16B3.8%
Portfolio Concentration
Top 3$4.24B13.8%
4–10$4.71B15.4%
11–25$4.62B15.1%
Rest$17.04B55.7%
Top 3 weight
13.8%
Top 10 weight
29.2%
Voting Authority Distribution
Total shares with voting rights: 236.91M
Sole
Full voting authority
208.87M
shares
% of voting shares88.2%
Shared
Joint voting authority
0.00
shares
% of voting shares0.0%
None
No voting authority
28.03M
shares
% of voting shares11.8%
Investment Discretion (by position count)
Sole278
Shared0
Other0
Dominant voting typeSole · 88.2% of voting shares
Institutional Holdings278
Rows:
NVIDIA CORPORATION
SOLEShares8.08M
TypeSH
Market value$1.62B
5.28%
Sole
6.43M
Shared
0.00
None
1.65M
ALPHABET INC
SOLEShares3.75M
TypeSH
Market value$1.34B
4.38%
Sole
3.12M
Shared
0.00
None
630.58K
ASCENDIS PHARMA A/S
SOLEShares4.80M
TypeSH
Market value$1.28B
4.18%
Sole
4.03M
Shared
0.00
None
766.96K
AXON ENTERPRISE INC
SOLEShares1.49M
TypeSH
Market value$836.14M
2.73%
Sole
1.19M
Shared
0.00
None
301.50K
FTAI AVIATION LTD
SOLEShares2.94M
TypeSH
Market value$794.61M
2.60%
Sole
2.54M
Shared
0.00
None
395.39K
APPLE INC
SOLEShares2.57M
TypeSH
Market value$744.75M
2.43%
Sole
1.96M
Shared
0.00
None
613.46K
COMFORT SYS USA INC
SOLEShares355.43K
TypeSH
Market value$704.45M
2.30%
Sole
287.83K
Shared
0.00
None
67.60K
BROADCOM INC
SOLEShares1.56M
TypeSH
Market value$587.98M
1.92%
Sole
1.23M
Shared
0.00
None
326.80K
MICROSOFT CORP
SOLEShares1.41M
TypeSH
Market value$527.56M
1.72%
Sole
1.07M
Shared
0.00
None
343.33K
HOWMET AEROSPACE INC
SOLEShares1.92M
TypeSH
Market value$516.61M
1.69%
Sole
1.43M
Shared
0.00
None
496.11K
ELI LILLY & CO
SOLEShares416.73K
TypeSH
Market value$499.84M
1.63%
Sole
328.22K
Shared
0.00
None
88.51K
SNOWFLAKE INC
SOLEShares1.74M
TypeSH
Market value$441.94M
1.44%
Sole
1.31M
Shared
0.00
None
423.78K
MKS INC.
SOLEShares928.62K
TypeSH
Market value$413.05M
1.35%
Sole
792.79K
Shared
0.00
None
135.83K
META PLATFORMS INC
SOLEShares677.39K
TypeSH
Market value$381.57M
1.25%
Sole
536.19K
Shared
0.00
None
141.19K
VERTIV HOLDINGS CO
SOLEShares1.05M
TypeSH
Market value$353.02M
1.15%
Sole
838.10K
Shared
0.00
None
216.26K
GE VERNOVA INC
SOLEShares241.27K
TypeSH
Market value$283.46M
0.93%
Sole
169.56K
Shared
0.00
None
71.71K
MICRON TECHNOLOGY INC
SOLEShares228.20K
TypeSH
Market value$263.41M
0.86%
Sole
186.40K
Shared
0.00
None
41.80K
VISA INC
SOLEShares762.40K
TypeSH
Market value$261.57M
0.85%
Sole
593.21K
Shared
0.00
None
169.19K
API GROUP CORP
SOLEShares6.15M
TypeSH
Market value$260.63M
0.85%
Sole
5.18M
Shared
0.00
None
970.39K
TAPESTRY INC
SOLEShares1.70M
TypeSH
Market value$248.34M
0.81%
Sole
1.46M
Shared
0.00
None
232.79K
RHYTHM PHARMACEUTICALS INC
SOLEShares2.21M
TypeSH
Market value$245.22M
0.80%
Sole
2.04M
Shared
0.00
None
169.87K
LIFE TIME GROUP HOLDINGS INC
SOLEShares6M
TypeSH
Market value$244.85M
0.80%
Sole
5.61M
Shared
0.00
None
388.15K
TAIWAN SEMICONDUCTOR MANUFAC
SOLEShares511K
TypeSH
Market value$244.04M
0.80%
Sole
364.12K
Shared
0.00
None
146.88K
GUARDANT HEALTH INC
SOLEShares1.62M
TypeSH
Market value$243.72M
0.80%
Sole
1.50M
Shared
0.00
None
124.61K
QUANTA SVCS INC
SOLEShares331.49K
TypeSH
Market value$238.69M
0.78%
Sole
242K
Shared
0.00
None
89.49K
| Issuer | Class | Shares | Type | Value / Portfolio % | Voting — Sole | Shared | None |
|---|---|---|---|---|---|---|---|
NVIDIA CORPORATIONSOLE | COM | 8.08M | SH | $1.62B 5.28% | 6.43M | 0.00 | 1.65M |
ALPHABET INCSOLE | CAP STK CL A | 3.75M | SH | $1.34B 4.38% | 3.12M | 0.00 | 630.58K |
ASCENDIS PHARMA A/SSOLE | ORD SHS | 4.80M | SH | $1.28B 4.18% | 4.03M | 0.00 | 766.96K |
AXON ENTERPRISE INCSOLE | COM | 1.49M | SH | $836.14M 2.73% | 1.19M | 0.00 | 301.50K |
FTAI AVIATION LTDSOLE | SHS | 2.94M | SH | $794.61M 2.60% | 2.54M | 0.00 | 395.39K |
APPLE INCSOLE | COM | 2.57M | SH | $744.75M 2.43% | 1.96M | 0.00 | 613.46K |
COMFORT SYS USA INCSOLE | COM | 355.43K | SH | $704.45M 2.30% | 287.83K | 0.00 | 67.60K |
BROADCOM INCSOLE | COM | 1.56M | SH | $587.98M 1.92% | 1.23M | 0.00 | 326.80K |
MICROSOFT CORPSOLE | COM | 1.41M | SH | $527.56M 1.72% | 1.07M | 0.00 | 343.33K |
HOWMET AEROSPACE INCSOLE | COM | 1.92M | SH | $516.61M 1.69% | 1.43M | 0.00 | 496.11K |
ELI LILLY & COSOLE | COM | 416.73K | SH | $499.84M 1.63% | 328.22K | 0.00 | 88.51K |
SNOWFLAKE INCSOLE | COM SHS | 1.74M | SH | $441.94M 1.44% | 1.31M | 0.00 | 423.78K |
MKS INC.SOLE | COM | 928.62K | SH | $413.05M 1.35% | 792.79K | 0.00 | 135.83K |
META PLATFORMS INCSOLE | CL A | 677.39K | SH | $381.57M 1.25% | 536.19K | 0.00 | 141.19K |
VERTIV HOLDINGS COSOLE | COM CL A | 1.05M | SH | $353.02M 1.15% | 838.10K | 0.00 | 216.26K |
GE VERNOVA INCSOLE | COM | 241.27K | SH | $283.46M 0.93% | 169.56K | 0.00 | 71.71K |
MICRON TECHNOLOGY INCSOLE | COM | 228.20K | SH | $263.41M 0.86% | 186.40K | 0.00 | 41.80K |
VISA INCSOLE | COM CL A | 762.40K | SH | $261.57M 0.85% | 593.21K | 0.00 | 169.19K |
API GROUP CORPSOLE | COM STK | 6.15M | SH | $260.63M 0.85% | 5.18M | 0.00 | 970.39K |
TAPESTRY INCSOLE | COM | 1.70M | SH | $248.34M 0.81% | 1.46M | 0.00 | 232.79K |
RHYTHM PHARMACEUTICALS INCSOLE | COM | 2.21M | SH | $245.22M 0.80% | 2.04M | 0.00 | 169.87K |
LIFE TIME GROUP HOLDINGS INCSOLE | COMMON STOCK | 6M | SH | $244.85M 0.80% | 5.61M | 0.00 | 388.15K |
TAIWAN SEMICONDUCTOR MANUFACSOLE | SPONSORED ADS | 511K | SH | $244.04M 0.80% | 364.12K | 0.00 | 146.88K |
GUARDANT HEALTH INCSOLE | COM | 1.62M | SH | $243.72M 0.80% | 1.50M | 0.00 | 124.61K |
QUANTA SVCS INCSOLE | COM | 331.49K | SH | $238.69M 0.78% | 242K | 0.00 | 89.49K |
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