SEC 13F Intelligence

Managers / Q1 2026

WESTFIELD CAPITAL MANAGEMENT CO LP

CIK 0001177719 · ONE FINANCIAL CENTER, 23RD FLOOR, BOSTON, MA, 02111 · 6174287100

Reported Value
$23.8B
Q1 2026
Positions
250
Filings on Record
30
2019–present window
Filed
May 11, 2026
original filing

Summary

Westfield Capital Management Co Lp reported $23.8B in U.S.-listed holdings across 250 positions for Q1 2026.

Its largest position, NVDA, represents 4.6% of the portfolio.

Compared with Q4 2025, the fund opened 46 new positions and exited 37.

Reported Value by Quarter

13F Reported Value
Q4 ’18: $11.7BQ4 ’18Q1 ’19: $13.1BQ2 ’19: $13.3BQ3 ’19: $12.5BQ4 ’19: $14.0BQ4 ’19Q1 ’20: $11.4BQ2 ’20: $14.5BQ3 ’20: $15.4BQ4 ’20: $16.9BQ4 ’20Q1 ’21: $16.1BQ2 ’21: $16.7BQ3 ’21: $16.6BQ4 ’21: $16.8BQ4 ’21Q1 ’22: $15.6BQ2 ’22: $12.7BQ3 ’22: $12.6BQ4 ’22: $12.96TQ4 ’22Q1 ’23: $14.2BQ2 ’23: $15.7BQ3 ’23: $14.7BQ4 ’23: $17.2BQ4 ’23Q1 ’24: $19.0BQ2 ’24: $20.4BQ3 ’24: $22.1BQ4 ’24: $23.0BQ4 ’24Q1 ’25: $20.5BQ2 ’25: $23.8BQ3 ’25: $23.8BQ4 ’25: $24.0BQ4 ’25Q1 ’26: $23.8Bfilingsflow.com

Portfolio Composition

By security type

Composition data arrives with ticker enrichment.

Quarter-over-Quarter Changes full breakdown →

Holdings — Q1 2026

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Filing History

QuarterReported ValuePositionsFiledTypeLinks
Q1 2026$23.8B250May 11, 202613F-HRchanges · EDGAR ↗
Q4 2025$24.0B241Feb 11, 202613F-HRchanges · EDGAR ↗
Q3 2025$23.8B235Nov 12, 202513F-HRchanges · EDGAR ↗
Q2 2025$23.8B239Aug 12, 202513F-HRchanges · EDGAR ↗
Q1 2025$20.5B244May 9, 202513F-HRchanges · EDGAR ↗
Q4 2024$23.0B239Feb 11, 202513F-HRchanges · EDGAR ↗
Q3 2024$22.1B247Nov 12, 202413F-HRchanges · EDGAR ↗
Q2 2024$20.4B248Aug 14, 202413F-HRchanges · EDGAR ↗
Q1 2024$19.0B244May 10, 202413F-HRchanges · EDGAR ↗
Q4 2023$17.2B239Feb 9, 202413F-HRchanges · EDGAR ↗
Q3 2023$14.7B234Nov 13, 202313F-HRchanges · EDGAR ↗
Q2 2023$15.7B227Aug 11, 202313F-HRchanges · EDGAR ↗
Q1 2023$14.2B222May 12, 202313F-HRchanges · EDGAR ↗
Q4 2022$12.96T226Feb 13, 202313F-HRchanges · EDGAR ↗
Q3 2022$12.6B230Nov 14, 202213F-HRchanges · EDGAR ↗
Q2 2022$12.7B235Aug 12, 202213F-HRchanges · EDGAR ↗
Q1 2022$15.6B235May 16, 202213F-HRchanges · EDGAR ↗
Q4 2021$16.8B244Feb 10, 202213F-HRchanges · EDGAR ↗
Q3 2021$16.6B235Nov 12, 202113F-HRchanges · EDGAR ↗
Q2 2021$16.7B241Aug 10, 202113F-HRchanges · EDGAR ↗
Q1 2021$16.1B243May 14, 202113F-HRchanges · EDGAR ↗
Q4 2020$16.9B247Feb 12, 202113F-HRchanges · EDGAR ↗
Q3 2020$15.4B235Nov 13, 202013F-HRchanges · EDGAR ↗
Q2 2020$14.5B230Aug 13, 202013F-HRchanges · EDGAR ↗
Q1 2020$11.4B216May 14, 202013F-HRchanges · EDGAR ↗
Q4 2019$14.0B231Feb 13, 202013F-HRchanges · EDGAR ↗
Q3 2019$12.5B234Nov 8, 201913F-HRchanges · EDGAR ↗
Q2 2019$13.3B243Aug 13, 201913F-HRchanges · EDGAR ↗
Q1 2019$13.1B246May 14, 201913F-HRchanges · EDGAR ↗
Q4 2018$11.7B240Feb 8, 201913F-HRchanges · EDGAR ↗

13F filings are due up to 45 days after quarter end, so holdings shown here lag the fund’s current book. Source: original SEC filing on EDGAR ↗.