SEC-registered wealth management firm Broker-dealer affiliated
William Blair & Company L.L.C.
As of its Form ADV filed March 31, 2026, William Blair & Company L.L.C., an SEC-registered, broker-dealer affiliated wealth management firm in Chicago, Illinois, reported $64.3 billion in regulatory assets under management across 39,781 accounts, ranking #5 among all wealth firms in Illinois by assets.
Registration
- Registration
- SEC-registered, Approved
- CRD number
- 1252
- SEC file number
- 801-688
- Registered since
- December 24, 1947
- Latest Form ADV filing
- March 31, 2026
- Organized as
- Limited Liability Company
- Fiscal year ends
- December
- Other offices
- 11
Key figures
- Regulatory assets under management
- $64.3 billion
- Discretionary
- $58.1 billion (90.3%)
- Non-discretionary
- $6.2 billion
- Accounts
- 39,781 (38,800 discretionary)
- Clients
- 38,171, approximate as reported
- Employees
- 492
- Advisory staff
- 231 performing investment advisory functions
- Average account
- $1.6 million
- Asset growth, 1 year
- 10.2% (from $58.3 billion a year earlier)
- Asset growth, 3-year annual rate
- 15.5% (from $41.7 billion three years earlier)
- Asset growth, 5-year annual rate
- 8.8% (from $42.2 billion five years earlier)
- Client growth, 1 year
- 1.7% (from 37,515)
Broker-dealer affiliated. The firm is itself a broker-dealer as well as an investment adviser (Form ADV Item 6.A(1)). It is ranked among all wealth firms, the directory's view that includes wirehouses and broker-dealer firms, not in the main lists of independent RIAs. How firms are classed.
Growth rates come from the SEC's yearly snapshots and are left blank when the years are not comparable.
Rankings
Among all wealth firms, including wirehouses and broker-dealer firms.
Assets over time
Data table
| As of | RAUM |
|---|---|
| October 1, 2010 | $44.3 billion |
| October 3, 2011 | $47.9 billion |
| October 1, 2012 | $44.0 billion |
| October 1, 2013 | $52.9 billion |
| October 1, 2014 | $66.8 billion |
| October 1, 2015 | $35.8 billion |
| October 3, 2016 | $16.3 billion |
| October 2, 2017 | $16.2 billion |
| October 1, 2018 | $32.4 billion |
| October 1, 2019 | $25.2 billion |
| October 1, 2020 | $33.0 billion |
| October 4, 2021 | $42.2 billion |
| October 3, 2022 | $50.0 billion |
| October 5, 2023 | $41.7 billion |
| October 1, 2024 | $50.0 billion |
| September 2, 2025 | $58.3 billion |
| October 2, 2026 | $64.3 billion |
Clients and services
Client mix
| Measure | Bar | RAUM |
|---|---|---|
| High net worth individuals 9,054 clients | $45.4 billion | |
| Corporations or other businesses 1,333 clients | $8.1 billion | |
| Individuals (other than high net worth) 26,242 clients | $7.3 billion | |
| Charitable organizations 31 clients | $1.8 billion | |
| Other investment advisers 1,146 clients | $1.4 billion | |
| Pension and profit sharing plans 364 clients | $379.1 million | |
| Pooled investment vehicles 1 client | $5.6 million |
How the firm is paid
- A percentage of assets under management
- Fixed fees
Advisory services
- Financial planning
- Portfolio management for individuals or small businesses
- Portfolio management for pooled investment vehicles
- Portfolio management for businesses or institutional clients
- Selection of other advisers
- Other
Financial planning clients (Item 5.H): 2700.
Wrap fee program sponsor or portfolio manager: yes.
Other business, affiliations and custody
Other business activities (Item 6.A)
- Broker-dealer
- Insurance broker or agent
Financial industry affiliations (Item 7.A)
- Broker-dealer
- Other investment adviser
- Commodity pool operator or commodity trading advisor
- Sponsor, general partner or managing member of pooled investment vehicles
Advises 21 private funds (Item 7.B).
Custody (Item 9)
The firm reported custody of client cash or securities, $55.0 million in total.
Investment adviser representatives
- IARs registered with the firm
- 329
- Also registered through a broker-dealer
- 326
- Employees who are IARs (Form ADV 5.B(3))
- 272
Designations held by the firm's IARs: CFA 24, CFP 18, ChFC 1, CIC 1.
Between 286 and 329 of the firm's 329 IARs are registered in jurisdictions that require IAR CE. The source counts registrations by jurisdiction, and many IARs are registered in more than one, so the exact number is not knowable from it. IAR CE requirements by state.
Counts only. AdvisorIQ does not list individual people.
Disclosures
On Form ADV Item 11 the firm answered yes to 6 disclosure questions. See the detail on IAPD.
Succession and acquired firms
On Form ADV Item 4 the firm did not report succeeding to another adviser's business.
Similar-sized firms in Illinois
| Firm | City | RAUM |
|---|---|---|
| Cresset Asset Management, LLC | Chicago | $78.9 billion |
| CIBC Private Wealth Advisors, Inc. | Chicago | $67.8 billion |
| Savant Wealth Management | Rockford | $55.6 billion |
| Choreo, LLC | Rockford | $19.1 billion |
| The Mather Group, LLC | Chicago | $13.4 billion |
The five wealth firms, broker-dealer affiliated firms included, nearest in regulatory assets with a main office in the same state.
Elsewhere
- William Blair & Company L.L.C. on IAPD: Form ADV, brochures and disclosure detail.
- Firm website: www.williamblair.com
- Wealth management firms in Illinois
Firm data as of October 2, 2026, from ia100226.zip. Figures are as the firm reported them; corrections are made on Form ADV and appear after the next monthly reload.
Data as of October 2, 2026, from Form ADV. Sources: SEC registered adviser data (ia100226.zip) and IAPD compilation reports. How the directory is built.