Firm profile

WESTFIELD CAPITAL MANAGEMENT COMPANY, L.P.

BOSTON, MACRD 146990Latest ADV March 11, 2026

Westfield Capital Management Company, L.P. is an SEC registered investment adviser organized as a limited partnership with a primary office location in Boston, MA. Its latest Form ADV filing, dated March 11, 2026, reports $24.4B in regulatory assets under management, 61 employee, and 1,118 accounts.

Assets Under Management
$24.4B
Employees
61
Offices
--
Total Clients
1,118
Primary office
BOSTON, MA
ONE FINANCIAL CENTER, BOSTON, MA, United States
ADV Item 1F location record

Contact and digital presence

ADV profile links

Leadership

6 roles identified
CEOWilliam A. Muggia
CCOKathryn A. Kearney
CFOKathryn A. Kearney

Advisory services offered

4 types reported
Portfolio management for businesses
Portfolio management for individuals and small businesses
Portfolio management for investment companies

Fee models offered

2 types reported
Asset based fees
Performance-based fees
Sources checked May 15, 2026

Client Coverage Demographics

Top client segmentHNWI represent 45.2% of total clients.
Top client categories% of clientsClients
1
HNWI
45.2%
505
2
Individuals
24.5%
274
3
Charitable
11.4%
127
4
Corporations
7.5%
84
5
Pension Plans
5.5%
61
Categories with <5 clients
Other investment advisers<5 clients

Regulatory Assets Under Management Breakdown

Total regulatory assets under management$24.4Bas of March 11, 2026
Discretionary100.0%
$24.4B
100% of total RAUM100.0%
Non-discretionary0.0%
$0
0% of total RAUM0.0%
All regulatory assets under management are discretionary.

Assets under management Growth by Quarter

Quarterly points use the latest ADV filing or SEC roster snapshot available in each quarter.

Latest AUM$24.4B
Total Accounts1,118
10Y AUM Change+$12.7B (+107.7%)

Employee Growth by Quarter

Quarterly points use the latest ADV filing or SEC roster snapshot available in each quarter.

Total Employees61
Clients per Employee18:1
10Y Employee Change-3 (-4.7%)

* Metrics are based on the latest available data, including Form ADV filings, brochures, and relationship summaries pulled from the SEC IAPD, and may be subject to change. Learn what is included in the Rialytix data. Please refer to the firm's official disclosures for the most accurate information using their CRD number. This is not investment advice.