X-17A-5: Submission Information

Report for the Period Beginning

01-01-2024

and Ending

12-31-2024

Type of Registrant

Broker-dealer

Security-based swap dealer

Major security-based swap participant

OTC derivatives dealer

Material Weakness

Does this submission include an accountant's report covering the compliance report that indentifies one or more material weaknesses?

Yes

X-17A-5: A. Registrant Identification

Name of Firm

WILLIAM BLAIR & COMPANY L.L.C.

Address of Principal Place of Business (Do not use P.O. Box No.)

Address 1

THE WILLIAM BLAIR BUILDING

Address 2

150 NORTH RIVERSIDE

City

CHICAGO

State/Country

ILLINOIS

Mailing Zip/ Portal Code

60606-1594

Name and Telephone Number of Person to Contact in Regard to this Report

Name

Brent Whitford

Telephone Number

3123648978

X-17A-5: B. Accountant Identification

Independent Public Accountant

Name - if individual, state last, first, and middle name

PricewaterhouseCoopers LLP

Address 1

1 N Wacker Drive

City

Chicago

State/Country

ILLINOIS

Mailing Zip/ Postal Code

60606

Check One

Certified Public Accountant
Radio button not checked

Certified Public Accountant not resident in United States or any of its possessions

X-17A-5: Signature

Oath or Affirmation

I, Michael Trimberger, swear (or affirm) that, to the best of my knowledge and belief, the financial report pertaining to the firm of WILLIAM BLAIR & COMPANY L.L.C., as of 12-31-2024, is true and correct. I further swear (or affirm) that neither the company nor any partner, proprietor, principal officer or director has any proprietary interest in any account classified solely as that of a customer, except as follows:

Signature

Michael Trimberger

Title

CFO

Notary Public

Checking this box acknowledges that this oath or affirmation has been notarized.

X-17A-5: Filer Information

Submission Contact Information