What Westfield Capital Management does

Westfield Capital Management Company, L.P. is an employee-owned, SEC-registered investment advisor headquartered at One Financial Center in Boston, Massachusetts. Founded in 1989, the firm specializes exclusively in U.S. growth equities and manages approximately $31B in firm-wide assets across nine disclosed strategies. As of 2026, Westfield employs 63 professionals organized around a team-based, research-driven investment process with disciplined risk management; firm leadership is headed by President, CEO and CIO Will Muggia (joined 1994, CIO since 2001), supported by Managing Partners covering Information Technology, Health Care/Biopharma, Software/Internet, Industrials, Consumer, and Financials sectors.

The firm's product platform spans the full market-capitalization spectrum through Growth Equity strategies — Small Cap Growth ($4.3B, 1989), Small/Mid Cap Growth ($4.8B, 1992), Mid Cap Growth ($4.3B, 1994), Large Cap Growth ($5.4B), All Cap Growth ($1.7B, 1989), and Select Growth ($2.9B, 2014, 35 or fewer holdings) — and Sector Focus strategies including Dividend Growth ($417M, 2010), Health Care ($28M, 2020), and Sustainable Growth ($101M, January 2016). Distribution occurs through direct institutional sales to pension funds, endowments, foundations, and family offices, sub-advisory mandates (e.g., Liberty All-Star Growth Fund), and a private wealth/family office channel, supported by active thought leadership including a quarterly Market Views webcast and the Westfield Insights newsletter.

Revenue is generated through investment management fees calculated as a percentage of assets under management (AUM), with strategies varying in fee structure and not publicly disclosed. The firm's investment approach emphasizes high-conviction active management, proprietary fundamental research, and disciplined risk management, with marketing messaging centered on employee ownership and long-tenured expertise. The firm maintains a domestic U.S. operating footprint with no disclosed international operations, and its technology stack is not publicly described beyond its proprietary research process.

Name

Westfield Capital Management

Legal name

Westfield Capital Management Company, L.P.

Website

https://westfieldcapital.com

Company type

Private

Founded year

1989

Operating status

Operating

Headcount range

51–100 employees

Short description

Westfield Capital Management is a Boston-based, employee-owned SEC-registered investment advisor founded in 1989 that manages approximately $31B across U.S. growth-equity strategies spanning the full market-cap spectrum and selected sector mandates, serving institutional investors, family offices, and wealth-management clients through direct sales and sub-advisory relationships.

Ownership category

akta.pro rank

Product category

Institutional Asset Management

NAICS

Other Financial Investment Activities (5239), Other Investment Pools and Funds (5259)

SIC

Investment Advice (6282)

akta.pro primary industry

Mid-Cap Equity (Active) (FSAAAIAB)

akta.pro secondary industries

Small-Cap Equity (Active) (FSAAAIAC), Large-Cap Equity (Active) (FSAAAIAA), Institutional Separate Accounts & SMAs (Mandates) (FSAAAGAL)

Keywords

• Institutional asset management
• Growth equity strategies
• Investment advisory services
• Separate account management
• Sub-advisory services

Headquarters

HQ city

Boston

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Investment Management Fees: Westfield Capital Management generates revenue through investment advisory fees charged on assets under management. As an employee-owned investment management firm managing $31B in assets across various growth equity strategies, the firm earns management fees typically calculated as a percentage of AUM.

Go-to-market motion1 record

Distribution channels3 records

Marketing channels5 records

Core offering

Westfield Capital Management is an employee-owned, SEC-registered investment advisor that manages approximately $31 billion in assets across U.S. growth equity strategies. The firm offers actively managed separate accounts spanning the full market capitalization spectrum (Small Cap, Small/Mid Cap, Mid Cap, Large Cap, All Cap, and Select Growth) plus sector-focused strategies (Dividend Growth, Health Care, and Sustainable Growth), delivered to institutional investors, family offices, and high net worth individuals and as sub-advisory mandates.

Product overview

Westfield Capital Management is an employee-owned investment management firm offering a unified platform of U.S. growth equity investment strategies. The firm manages $31B in assets across two main product categories: Growth Equity strategies spanning the full market capitalization spectrum (Small Cap, Small/Mid Cap, Mid Cap, Large Cap, All Cap, and Select Growth), and Sector Focus strategies tailored to specific investment themes (Dividend Growth, Health Care, and Sustainable Growth). All strategies are grounded in the firm's core philosophy of disciplined research-driven investing to uncover underappreciated growth and deliver long-term value.

Differentiator

Problem solved

Functional benefit

Products and services

• Small Cap Growth Targets high-quality small caps with scalable models, consistent execution, and underappreciated earnings potential. Strategy AUM: $4.3B, Inception: 1989.
• Small/Mid Cap Growth (SMID) Focused on small and mid-cap companies with strong fundamentals and the potential for sustained earnings growth. Strategy AUM: $4.8B, Inception: April 1992, Benchmark: Russell 2500 Growth Index.
• Mid Cap Growth Invests in mid-cap companies with underappreciated earnings power, solid balance sheets, and competitive advantages. Strategy AUM: $4.3B, Inception: 1994.
• Large Cap Growth Targets high-quality large caps with sustainable earnings, capital discipline, and long-term growth potential. Strategy AUM: $5.4B.
• All Cap Growth Seeks to capture growth across all market caps through disciplined execution and flexible capital allocation. Strategy AUM: $1.7B, Inception: July 1989, Benchmark: Russell 3000 Growth Index.
• Select Growth Concentrated portfolio of high-conviction growth companies with asymmetrical risk/rewards, reflecting highest conviction ideas sized to drive alpha while managing risk. Strategy AUM: $2.9B, Inception: January 2014, 35 or fewer holdings.
• Dividend Growth Targets high quality dividend growers aiming to deliver consistent returns and reduced volatility over time. Strategy AUM: $417M, Inception: 2010.
• Health Care Sector Focus Targets health care companies driving innovation and value creation, aiming to capitalize on secular growth trends. Strategy AUM: $28M, Inception: 2020.
• Sustainable Growth High-conviction, low-turnover large-cap growth strategy combining deep research and independent ESG analysis to identify high-quality businesses with durable growth, sustainable advantages, and attractive valuations. Strategy AUM: $101M, Inception: January 2016, Benchmark: Russell 1000 Growth Index, 35-40 holdings.

Segments2 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Scale indicators11 records

Recent moves6 records

Expansion highlights5 records

Market position

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/53665

Revenue estimate

Valuation estimate

Number of profiles

Profiles11 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments9 records

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Westfield Capital Management