# Westfield Capital Management Company, L.P.

> Westfield Capital Management Company, L.P. is an SEC-registered investment advisory firm in Boston, MA, registered since 2008, reporting over $5 billion in regulatory assets under management in its Form ADV filing dated July 1, 2026.

- CRD: 146990
- Filed as: WESTFIELD CAPITAL MANAGEMENT COMPANY, L.P.
- Registration: SEC-registered investment adviser (status as filed: Approved)
- Location: Boston, MA
- Filing period: October 2026
- Form ADV filing dated: July 1, 2026
- SEC record (IAPD): https://adviserinfo.sec.gov/firm/summary/146990
- AdvisorCensus page: https://advisorcensus.com/firm/westfield-capital-management-company-l-p-boston-ma-146990

## Quick answers

**How is Westfield Capital Management Company, L.P. compensated?**
On its Form ADV (Item 5.E, October 2026), Westfield Capital Management Company, L.P. reports these compensation arrangements: a percentage of assets under its management; performance-based fees. The amounts are in Item 5 of its Form ADV Part 2A brochure.

**Where is Westfield Capital Management Company, L.P. located?**
Westfield Capital Management Company, L.P.'s principal office is in Boston, MA, according to its Form ADV.

**Is Westfield Capital Management Company, L.P. registered with the SEC or a state?**
Westfield Capital Management Company, L.P. is an SEC-registered investment advisory firm, registered since 2008. Status as filed: Approved. CRD 146990.

**How much does Westfield Capital Management Company, L.P. manage?**
Westfield Capital Management Company, L.P. reports $29,807,982,355 in regulatory assets under management in its Form ADV filing dated July 1, 2026 (100% discretionary).

**How have Westfield Capital Management Company, L.P.'s assets and staff changed since 2021?**
In the Form ADV data for Westfield Capital Management Company, L.P.: Regulatory assets under management: $17,123,083,785 in the October 2021 data and $29,807,982,355 in the October 2026 data, up 74%. Total employees: 61 in October 2021 and 63 in October 2026. Assets under management move with markets as well as with clients coming and going.

**What types of clients does Westfield Capital Management Company, L.P. serve?**
By number of clients on Form ADV Item 5.D: individuals (other than high net worth individuals) (8,398); high net worth individuals (512); pension and profit sharing plans (but not the plan participants or government pension plans) (177).

**Which custodians does Westfield Capital Management Company, L.P. use?**
Westfield Capital Management Company, L.P.'s most recent Form ADV filing (Schedule D, Section 5.K(3)) lists State Street Bank and Trust Co., The Bank of New York Mellon and The Northern Trust Company as custodians holding 10% or more of its separately managed account assets.

**Does Westfield Capital Management Company, L.P. report any disciplinary disclosures?**
Reports no disclosure items on Form ADV Item 11. The detail of any item is on the firm's SEC record: https://adviserinfo.sec.gov/firm/summary/146990

**What changed in Westfield Capital Management Company, L.P.'s recent Form ADV filings?**
In the August 2026 filing data: Employees performing advisory functions went from 17 to 19. Regulatory assets under management went from $24,404,194,926 to $29,807,982,355 (+22%).

## From the Form ADV filing

### Compensation (Item 5.E)
- A percentage of assets under your management
- Performance-based fees

### Custodians (Schedule D, Section 5.K(3))
- State Street Bank and Trust Co.
- The Bank of New York Mellon
- The Northern Trust Company

Custodians holding 10% or more of the firm's separately managed account assets, as filed on Form ADV (Schedule D, Section 5.K(3)). A custodian holds client assets; it does not endorse or supervise the firm. AdvisorCensus has no relationship with any custodian.

### Regulatory assets under management (Item 5.F)
- Total: $29,807,982,355
- Discretionary: $29,807,982,355
- Non-discretionary: $0

### Clients (Item 5.D)

| Client type | Clients | Assets |
| --- | --- | --- |
| Individuals (other than high net worth individuals) | 8,398 | $698,778,053 |
| High net worth individuals | 512 | $1,339,364,964 |
| Banking or thrift institutions | 0 | $0 |
| Investment companies | 15 | $9,996,040,566 |
| Business development companies | 0 | $0 |
| Pooled investment vehicles (other than investment companies and business development companies) | 15 | $4,517,391,455 |
| Pension and profit sharing plans (but not the plan participants or government pension plans) | 177 | $6,368,871,411 |
| Charitable organizations | 138 | $1,437,967,336 |
| State or municipal government entities (including government pension plans) | 38 | $4,292,131,725 |
| Other investment advisers | 1 | $661,015,631 |
| Insurance companies | 0 | $0 |
| Sovereign wealth funds and foreign official institutions | 0 | $0 |
| Corporations or other businesses not listed above | 97 | $496,421,214 |
| Other | 0 | $0 |

### Advisory services (Item 5.G)
- Portfolio management for individuals and/or small businesses
- Portfolio management for investment companies (and business development companies)
- Portfolio management for pooled investment vehicles (other than investment companies)
- Portfolio management for businesses (other than small businesses) or institutional clients

### Firm details
- Registered since: 2008 (18 years)
- Employees: 63 total, 19 performing advisory functions
- Wrap fee program participation: Yes
- States registered or notice-filed: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, PR, RI, SC, SD, TN, TX, UT, VA, VI, VT, WA, WI, WV, WY
- Disclosures (Item 11): Reports no disclosure items on Form ADV Item 11.

### Websites listed on Form ADV (Item 1.I)
- westfieldcapital.com
- LinkedIn @WESTFIELD-CAPITAL-MANAGEMENT
- X @WESTFIELD_CAP

## Assets and staff over time

| Data period | Regulatory assets under management | Employees | Filing dated |
| --- | --- | --- | --- |
| October 2021 | $17,123,083,785 | 61 | September 8, 2021 |
| October 2022 | $17,023,240,581 | 59 | August 4, 2022 |
| October 2023 | $13,315,528,816 | 59 | September 28, 2023 |
| October 2024 | $17,556,838,117 | 59 | September 10, 2024 |
| October 2025 | $23,551,448,142 | 60 | April 30, 2025 |
| October 2026 | $29,807,982,355 | 63 | July 1, 2026 |

Regulatory assets under management: $17,123,083,785 in the October 2021 data and $29,807,982,355 in the October 2026 data, up 74%.
Total employees: 61 in October 2021 and 63 in October 2026.

## Changes in the filing (last 12 months)

### August 2026
- Employees performing advisory functions went from 17 to 19.
- Regulatory assets under management went from $24,404,194,926 to $29,807,982,355 (+22%).

### April 2026
- Employees performing advisory functions went from 19 to 17.

### November 2025
- Updated its list of owners and control persons (Schedule A).

## Source

Form ADV as filed, October 2026. Values appear as filed. Cite as: AdvisorCensus. Westfield Capital Management Company, L.P. (CRD 146990): Form ADV filing data as of October 2026.