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WILLIAM BLAIR & COMPANY L.L.C.
CRD 1252File 801-688
APPROVED
Retail clients
Custody
Disclosure events
Filing as of Mar 31, 2026
Feed vintage Oct 1, 2026
Regulatory AUM
$64.28B
Top 10% of cohort (national)
Discretionary AUM
$58.08B
Non-discretionary $6.21B
Clients
38,171
39,781 accounts
Employees
492
Top 10% of cohort in IL
Identity & registration
ADV Item 1- Organization form
- Limited Liability Company
- Firm type
- Registered
- SEC region
- CHRO
- Registration date
- Dec 24, 1947
- Principal office
- 150 NORTH RIVERSIDE PLAZA, CHICAGO, IL, 60606
- Phone
- 312-236-1600
- Website
- https://www.williamblair.com
Assets & accounts
ADV Item 5F- Total regulatory AUM
- $64.28B
- Discretionary AUM
- $58.08B
- Non-discretionary AUM
- $6.21B
- Discretionary accounts
- 38,800
- Non-discretionary accounts
- 981
- Total accounts
- 39,781
- AUM per client
- $1.7M
Clients by type
ADV Item 5D| Client type | Clients | AUM |
|---|---|---|
| Other | 1,333 | $8.06B |
| Charitable organizations | 31 | $1.77B |
| Other investment advisers | 1,146 | $1.39B |
| High net worth individuals | 9,054 | $45.35B |
| Pooled investment vehicles | 1 | $5.6M |
| Pension and profit sharing plans | 364 | $379.1M |
| Individuals (other than high net worth individuals) | 26,242 | $7.33B |
Compensation & activities
ADV Items 5E, 5GCompensation
- Fixed fees
- A percentage of assets under your management
Advisory activities
- Other advisory activities
- Financial planning services
- Selection of other advisers
- Portfolio management for businesses
- Portfolio management for pooled investment vehicles
- Portfolio management for individuals and/or small businesses
Custody
ADV Item 9- Firm Custody Cash
- No
- Firm Custody Assets
- No
- Firm Custody Clients
- No
- Firm Custody Securities
- Yes
- Related Person Custody Cash
- Yes
- Related Person Custody Assets
- No
- Related Person Custody Clients
- No
- Related Person Custody Securities
- No
Disclosure events
ADV Item 11- Q11
- Q11C1
- Q11C2
- Q11C4
- Q11C5
- Q11D2
- Q11E2
Filed changes
| Date | Field | From | To | Change |
|---|---|---|---|---|
| Apr 1, 2026 | Employees | 469 | 492 | increased by23 |
| Apr 1, 2026 | Custody | No | Yes | |
| Apr 1, 2026 | Clients | 37,515 | 38,171 | increased by656 |
| Apr 1, 2026 | AUM | $58,329,726,421 | $64,284,844,374 | increased by$5,955,117,953 |
| Apr 1, 2026 | Accounts | 37,973 | 39,781 | increased by1,808 |
| May 1, 2025 vs Oct 1, 2022 | Employees | 326 | 469 | increased by143 |
| May 1, 2025 vs Oct 1, 2022 | Clients | 29,267 | 37,515 | increased by8,248 |
| May 1, 2025 vs Oct 1, 2022 | AUM | $49,965,190,648 | $58,329,726,421 | increased by$8,364,535,773 |
| May 1, 2025 vs Oct 1, 2022 | Accounts | 39,913 | 37,973 | decreased by1,940 |
| Apr 1, 2022 | Employees | 303 | 326 | increased by23 |
| Apr 1, 2022 | Clients | 21,627 | 29,267 | increased by7,640 |
| Apr 1, 2022 | AUM | $42,225,714,120 | $49,965,190,648 | increased by$7,739,476,528 |
| Apr 1, 2022 | Accounts | 33,537 | 39,913 | increased by6,376 |
| Apr 1, 2021 | Registration | — | APPROVED |
On Form 5500, an adviser usually appears as a plan service provider (Schedule C), not the plan sponsor.
See plans that list “WILLIAM BLAIR” as a service provider on 5500mcp →Matched by name only — Form ADV and Form 5500 share no identifier, and names are searched loosely (“WILLIAM BLAIR” may also match similarly-named firms). Confirm identity against each filing.
Every value above is reproduced from this firm's Form ADV filing. Fields the firm left blank are shown as “Not reported” rather than filled in from other sources.