WESTFIELD CAPITAL MANAGEMENT CO LP
Q1 2024 Form 13-F

BOSTON, MASSACHUSETTS
CIK 0001177719 · CRD 146990 · SEC-registered investment adviser
$19.0B Reported Value Total

WESTFIELD CAPITAL MANAGEMENT COMPANY, L.P. reports 794 total accounts under management (AUM). There are 794 discretionary accounts valued at $17,556,838,117, and 0 non-discretionary accounts.

Source: Form ADV filed * Note that certain holdings are exempt from Form 13-F reporting, so the AUM totals may be greater than the Form 13-F total.
SEC Registered Discretionary Manager
Firm Brochure (Part 2A) Client Relationship Summary (Form CRS)
Private funds (Form ADV)
11 funds · $185.4M gross asset value
Other: $68.8M · Hedge Fund: $34.8M · Private Equity Fund: $128.8K
Source: Form ADV filed 2026-07-01
Reported value
$19.0B
Quarter over quarter
+12.1%
Holdings
244
Top-10 concentration
24.0%

Filing Structure

Reports holdings for

Holdings reported by

Key People

Form ADV owners & control persons
William Albert Muggia
MEMBER OF MANAGEMENT COMMITTEE
Kathryn Ann Kearney
PARTNER, CHIEF FINANCIAL OFFICER AND CHIEF COMPLIANCE OFFICER
Richard Dailyong Lee
CHIEF INVESTMENT OFFICER
Q4 2023
Q2 2024
Go to latest

Coverage begins with the second quarter of 2013. Earlier quarters are not shown while their accuracy is being verified.

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Q1 2024 13F filing summary

Period of report March 31, 2024
Filed May 10, 2024
Form 13F-HR
Reported value $19.0B
Positions 244
Change in reported value +11.0%
New positions 32
Exited positions 27
Position turnover 21.8%
Top-10 concentration 24.0%

13F filings by quarter

Quarter Positions Value
Q2 2026 13F
Filed Aug 12, 2026
 278 $30.6B
Q1 2026 13F
Filed May 11, 2026
 250 $23.8B
Q4 2025 13F
Filed Feb 11, 2026
 241 $24.0B
Q3 2025 13F
Filed Nov 12, 2025
 235 $23.8B
Q2 2025 13F
Filed Aug 12, 2025
 239 $23.8B
Q1 2025 13F
Filed May 9, 2025
 244 $20.5B
Q4 2024 13F
Filed Feb 11, 2025
 239 $23.0B
Q3 2024 13F
Filed Nov 12, 2024
 247 $22.1B
Q2 2024 13F
Filed Aug 14, 2024
 248 $20.4B
Q1 2024 13F
Filed May 10, 2024
 244 $19.0B
Q4 2023 13F
Filed Feb 9, 2024
 239 $17.2B
Q3 2023 13F
Filed Nov 13, 2023
 234 $14.7B
Q2 2023 13F
Filed Aug 11, 2023
 227 $15.7B
Q1 2023 13F
Filed May 12, 2023
 222 $14.2B
Q4 2022 13F
Filed Feb 13, 2023
 226 $13.0B
Q3 2022 13F
Filed Nov 14, 2022
 230 $12.6B
Q2 2022 13F
Filed Aug 12, 2022
 235 $12.7B
Q1 2022 13F
Filed May 16, 2022
 235 $15.6B
Q4 2021 13F
Filed Feb 10, 2022
 244 $16.8B
Q3 2021 13F
Filed Nov 12, 2021
 235 $16.6B

33 earlier quarters on file — choose one from the quarter menu above.

Top 20 holdings · Q1 2024

# Holding Reported value % of portfolio
1 MSFT MICROSOFT CORP $640.7M 3.36%
2 ASND ASCENDIS PHARMA A/S $616.1M 3.23%
3 AAPL APPLE INC $555.1M 2.91%
4 NVDA NVIDIA CORPORATION $542.1M 2.85%
5 AMZN AMAZON COM INC $475.0M 2.49%
6 GOOGL ALPHABET INC $446.2M 2.34%
7 TDG TRANSDIGM GROUP INC $388.4M 2.04%
8 META META PLATFORMS INC $341.2M 1.79%
9 BLDR BUILDERS FIRSTSOURCE INC $288.1M 1.51%
10 V VISA INC $284.7M 1.49%
11 VRT VERTIV HOLDINGS CO $277.6M 1.46%
12 AXON AXON ENTERPRISE INC $221.9M 1.17%
13 NOW SERVICENOW INC $214.5M 1.13%
14 DXCM DEXCOM INC $213.5M 1.12%
15 FIX COMFORT SYS USA INC $211.9M 1.11%
16 UNH UNITEDHEALTH GROUP INC $211.1M 1.11%
17 ICLR ICON PLC $180.4M 0.95%
18 CRM SALESFORCE INC $177.9M 0.93%
19 AME AMETEK INC $174.4M 0.92%
20 OPCH OPTION CARE HEALTH INC $173.4M 0.91%

Values as reported on the Q1 2024 Form 13F. Every position is in the holdings table below.

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