William Blair Investment Management, LLC

Registered investment adviser · Chicago, IL · CRD #173961

Form ADV data as of 2026-09-01

Regulatory assets

$65.60 billion

Total accounts

682

Employees

388

Disclosure events

Firm details

Website: https://www.instagram.com/williamblairim
Telephone: 312-236-1600
SEC file number: 801-80640
Most recent Form ADV filing: 2026-04-09
SEC record: View this firm on the SEC's IAPD site

Disciplinary disclosures

This firm reports 3 disclosure questions answered Yes, covering 3 reported events. Form ADV Item 11 covers charges and pending proceedings as well as findings, so a Yes answer is not itself a finding of wrongdoing. The underlying detail is filed with the SEC.

SEC or CFTC found a violation of its regulations or statutes
SEC or CFTC entered an order in connection with investment-related activity
SEC or CFTC imposed a civil money penalty or a cease-and-desist order

Assets and accounts

Provides continuous and regular supervisory or management services	Yes
Discretionary regulatory assets under management	$65.60 billion
Non-discretionary regulatory assets under management	$0
Total regulatory assets under management	$65.60 billion
Discretionary accounts	682
Non-discretionary accounts	0
Total accounts	682
Regulatory assets under management attributable to non-U.S. persons	$7.58 billion

People

Total employees (excluding clerical)	388
Employees performing investment advisory functions (including research)	142
Employees who are registered representatives of a broker-dealer	119
Employees registered as investment adviser representatives with a state	0
Employees registered as IARs for another investment adviser	25
Employees who are licensed insurance agents	0
Firms or persons who solicit advisory clients on the firm's behalf	4

Custody

Has custody of client cash or bank accounts	Yes
Has custody of client securities	Yes
Client funds and securities held in the firm's custody	$464.4 million
Clients for whom the firm has custody	4
A related person has custody of client cash or bank accounts	Yes
A related person has custody of client securities	Yes
Client funds and securities held in a related person's custody	$13.7 million
Clients for whom a related person has custody	1
The firm acts as a qualified custodian	No
A related person acts as a qualified custodian	No
Number of persons acting as qualified custodians for the firm's clients	2

How the firm is compensated

A percentage of assets under managementPerformance-based fees

Advisory services offered

Portfolio management for individuals and/or small businessesPortfolio management for investment companiesPortfolio management for pooled investment vehiclesPortfolio management for businesses or institutional clients

Other business activities

Commodity pool operator or commodity trading advisor

Affiliated related persons

Broker-dealer, municipal securities dealer, or government securities broker or dealerOther investment adviser (including financial planners)Commodity pool operator or commodity trading advisorSponsor, general partner, or managing member of pooled investment vehicles

Reported conflicts of interest

Form ADV Items 8 asks advisers to disclose arrangements that may create a conflict with client interests. This firm answered Yes to:

Buys securities from or sells securities to advisory clients (principal transactions)
Buys or sells for itself securities it also recommends to clients
Recommends securities in which it has another proprietary interest
Executes agency cross transactions involving advisory client securities
Recommends securities for which it serves as underwriter or general partner
Recommends securities in which it has another sales interest
Brokers or dealers selected under 8.C.(3) are related persons
Recommends brokers or dealers to clients
Brokers or dealers recommended under 8.E. are related persons
Receives soft dollar benefits
Compensates a non-employee for client referrals
Provides employee compensation specifically for obtaining clients

Client types

Type of client	Clients	Assets
High net worth individuals	2	$18.3 million
Investment companies	29	$15.84 billion
Pooled investment vehicles (other than investment companies and BDCs)	51	$22.15 billion
Pension and profit sharing plans (not the participants or government plans)	73	$11.85 billion
Charitable organizations	68	$2.34 billion
State or municipal government entities (including government pension plans)	54	$11.93 billion
Other investment advisers	1	$320.7 million
Insurance companies	4	$23.5 million
Sovereign wealth funds and foreign official institutions	4	$721.5 million
Corporations or other businesses not listed above	10	$209.5 million
Other	386	$192.7 million