SEC 13F Intelligence

Managers / Q1 2026

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC

CIK 0001644956 · 150 NORTH RIVERSIDE PLAZA, CHICAGO, IL, 60606 · 312-236-1600

Reported Value
$30.3B
Q1 2026
Positions
413
Filings on Record
30
2019–present window
Filed
May 8, 2026
original filing

Summary

William Blair Investment Management, Llc reported $30.3B in U.S.-listed holdings across 413 positions for Q1 2026.

Its largest position, TSM, represents 6.2% of the portfolio.

Compared with Q4 2025, the fund opened 47 new positions and exited 47.

Reported Value by Quarter

13F Reported Value
Q4 ’18: $20.1BQ4 ’18Q1 ’19: $23.8BQ2 ’19: $23.8BQ3 ’19: $23.4BQ4 ’19: $25.1BQ4 ’19Q1 ’20: $20.5BQ2 ’20: $24.6BQ3 ’20: $25.7BQ4 ’20: $30.0BQ4 ’20Q1 ’21: $30.9BQ2 ’21: $31.9BQ3 ’21: $35.5BQ4 ’21: $37.0BQ4 ’21Q1 ’22: $33.5BQ2 ’22: $27.0BQ3 ’22: $25.3BQ4 ’22: $26.14TQ4 ’22Q1 ’23: $28.7BQ2 ’23: $31.2BQ3 ’23: $30.1BQ4 ’23: $34.4BQ4 ’23Q1 ’24: $38.7BQ2 ’24: $38.1BQ3 ’24: $40.5BQ4 ’24: $40.9BQ4 ’24Q1 ’25: $35.6BQ2 ’25: $37.7BQ3 ’25: $38.7BQ4 ’25: $35.9BQ4 ’25Q1 ’26: $30.3Bfilingsflow.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$30.3B413May 8, 202613F-HRchanges · EDGAR ↗
Q4 2025$35.9B413Feb 9, 202613F-HRchanges · EDGAR ↗
Q3 2025$38.7B414Nov 12, 202513F-HRchanges · EDGAR ↗
Q2 2025$37.7B417Jul 29, 202513F-HRchanges · EDGAR ↗
Q1 2025$35.6B423May 9, 202513F-HRchanges · EDGAR ↗
Q4 2024$40.9B433Feb 10, 202513F-HRchanges · EDGAR ↗
Q3 2024$40.5B412Nov 8, 202413F-HRchanges · EDGAR ↗
Q2 2024$38.1B411Aug 8, 202413F-HRchanges · EDGAR ↗
Q1 2024$38.7B410May 8, 202413F-HRchanges · EDGAR ↗
Q4 2023$34.4B406Feb 9, 202413F-HRchanges · EDGAR ↗
Q3 2023$30.1B398Nov 9, 202313F-HRchanges · EDGAR ↗
Q2 2023$31.2B395Aug 11, 202313F-HRchanges · EDGAR ↗
Q1 2023$28.7B393May 12, 202313F-HRchanges · EDGAR ↗
Q4 2022$26.14T401Feb 9, 202313F-HRchanges · EDGAR ↗
Q3 2022$25.3B387Nov 9, 202213F-HRchanges · EDGAR ↗
Q2 2022$27.0B403Aug 10, 202213F-HRchanges · EDGAR ↗
Q1 2022$33.5B441May 11, 202213F-HRchanges · EDGAR ↗
Q4 2021$37.0B427Feb 14, 202213F-HRchanges · EDGAR ↗
Q3 2021$35.5B431Nov 10, 202113F-HRchanges · EDGAR ↗
Q2 2021$31.9B465Aug 12, 202113F-HRchanges · EDGAR ↗
Q1 2021$30.9B367May 13, 202113F-HRchanges · EDGAR ↗
Q4 2020$30.0B356Feb 9, 202113F-HRchanges · EDGAR ↗
Q3 2020$25.7B343Nov 6, 202013F-HRchanges · EDGAR ↗
Q2 2020$24.6B341Aug 12, 202013F-HRchanges · EDGAR ↗
Q1 2020$20.5B339May 8, 202013F-HRchanges · EDGAR ↗
Q4 2019$25.1B356Feb 12, 202013F-HRchanges · EDGAR ↗
Q3 2019$23.4B357Nov 12, 201913F-HRchanges · EDGAR ↗
Q2 2019$23.8B372Aug 9, 201913F-HRchanges · EDGAR ↗
Q1 2019$23.8B406May 10, 201913F-HRchanges · EDGAR ↗
Q4 2018$20.1B404Feb 13, 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 ↗.