William Blair &
Asset Manager SEC-registered adviser
Legal name: William Blair & Company L.L.C.
AUM
$64.3B
Regulatory AUM
Private funds
21
Private Equity 21
Private fund assets
$114.7M
Gross asset value
Employees
492
Last Form D raise
Dec 2025
Most recent fund filing
From SEC Form ADV filing (filed Mar 31, 2026). View on SEC
People(1)
Owners and executive officers named on the firm's SEC Form ADV.
B
Funds(21)
Private funds reported on Form ADV, with amounts raised from the funds' SEC Form D filings.
| Fund | Type | Gross assets | Raised (Form D) | Investors | Last Form D | Recency |
|---|---|---|---|---|---|---|
| William Blair Mb Investments, L.P. - Oc 2025 Series | Private Equity | $2.5M | — | — | Dec 2025 | Warm |
| William Blair Mb Investments, LP - Cxt 2022 Series | Private Equity | $4.8M | — | — | Oct 2022 | Cold |
| William Blair Mb Investments, LP - Brpe Fiii 2022 Series | Private Equity | $79K | — | — | Jun 2022 | Cold |
| William Blair Mb Investments, L.P. - Ityc 2022 Series | Private Equity | $2.5M | — | — | Mar 2022 | Cold |
| William Blair Mb Investments, L.P. - Tcp Fiii 2022 Series | Private Equity | $4.5M | — | — | Mar 2022 | Cold |
| William Blair Mb Investments, LP - Hii 2022 Eries | Private Equity | $6.3M | — | — | Mar 2022 | Cold |
| William Blair Mb Investments, L.P. - Pcti 2022 Series | Private Equity | $6.8M | — | — | Feb 2022 | Cold |
| William Blair Mb Investments, L.P. - Fici 2022 Series | Private Equity | $9.7M | — | — | Feb 2022 | Cold |
| William Blair Mb Investments, LP - Hc Fii 2021 Series | Private Equity | $7.5M | — | — | Dec 2021 | Cold |
| William Blair Mb Investments, L.P. - M13v Fiii 2021 Series | Private Equity | $6.1M | — | — | Nov 2021 | Cold |
| William Blair Mb Investments, L.P. - Mog Fiii 2021 Series | Private Equity | $6.4M | — | — | Oct 2021 | Cold |
| William Blair Mb Investments, L.P. - Ugsi 2021 Series | Private Equity | $14.2M | — | — | Aug 2021 | Cold |
| William Blair Mb Investments, L.P. - Vmi 2021 Series | Private Equity | $20.7M | — | — | Aug 2021 | Cold |
| William Blair Mb Investments, L.P. - Ev Fii 2021 Series | Private Equity | $1.5M | — | — | Jun 2021 | Cold |
| William Blair Mb Investments, L.P. - Hv Fiii 2021 Series | Private Equity | $1.5M | — | — | Apr 2021 | Cold |
Board seats
Companies whose SEC Form D filings name one of this firm's people as a director, matched by name and office ZIP code.
No board seats matched from SEC filings yet.
Regulatory identifiers
- CRD number
- 1252
- SEC file number
- 801-688
- CIK
- 12518
Sources
- SEC Form ADV Oct 14, 2026