![Brian Posner](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="%231b1b1b" class="bi bi-person-fill" viewBox="0 0 16 16"><path d="M3 14s-1 0-1-1 1-4 6-4 6 3 6 4-1 1-1 1zm5-6a3 3 0 1 0 0-6 3 3 0 0 0 0 6"/></svg>)
Brian Posner
Director/Board Member at
ARCH CAPITAL GROUP LTD.
Net worth: 11 M $ as of 31/05/2026
Profile
Brian S.
Posner was the founder of Hygrove Partners LLC, founded in 2000, where the title held was Managing Partner from 2000 to 2006.
Mr. Posner is the founder of Point Rider Group LLC, founded in 2008, holding the title of President since 2008.
Current jobs include Independent Director at Arch Capital Group Ltd. since 2010, Independent Director at Dyne Therapeutics, Inc. starting in 2025, Trustee at AQR Funds, Trustee at Northwestern University, Member-Supervisory Board at Biogen GmbH since 2008, and Trustee at Northwestern University Clinical & Translational Sciences Institute.
Former jobs include President, CEO & Chief Investment Officer at ClearBridge Investments LLC from 2006 to 2008, Chairman at Bioverativ, Inc. from 2017 to 2018, Director at Sotheby's Holdings, Inc. from 2000 to 2003, Independent Director at Biogen, Inc. from 2008 to 2022, Director at Anadys Pharmaceuticals, Inc. in 2011, Independent Director at BG Medicine, Inc. from 2013 to 2015, Director at RiverPark Funds Trust, Director at Biogen Idec New Ventures, Inc., Portfolio Manager at Fidelity Management & Research Co. LLC from 1987 to 1995, Portfolio Manager at Warburg Pincus Asset Management, Inc. from 1997 to 1998, and Portfolio Manager at Credit Suisse Asset Management LLC from 1997 to 1998.
Education includes an undergraduate degree from Northwestern University conferred in 1983 and an MBAistration from The University of Chicago Booth School of Business conferred in 1987.
Known holdings in public companies
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
| 05/05/2026 | 122,175 ( 0.03% ) | 11 M $ | 31/05/2026 | |
| 08/06/2026 | 24,500 ( 0.01% ) | 473 585 $ | 31/05/2026 |
Brian Posner active positions
| Companies | Position | Start |
|---|---|---|
| ARCH CAPITAL GROUP LTD. | Director/Board Member | 04/11/2010 |
| DYNE THERAPEUTICS, INC. | Director/Board Member | 01/10/2025 |
Northwestern University Clinical & Translational Sciences Inst
 Northwestern University Clinical & Translational Sciences Inst Miscellaneous Commercial ServicesCommercial Services Provides research services to scientific discoveries | Director/Board Member | - |
Biogen GmbH
 Biogen GmbH Pharmaceuticals: MajorHealth Technology Discovers, develops, manufactures and supplies pharmaceutical products | Director/Board Member | 01/01/2008 |
AQR Funds
 AQR Funds Investment Trusts/Mutual FundsMiscellaneous Operates as an open-ended investment fund | Director/Board Member | - |
Northwestern University
 Northwestern University Other Consumer ServicesConsumer Services Functions as a College/University | Director/Board Member | - |
Point Rider Group LLC | Founder | 01/03/2008 |
Former positions of Brian Posner
| Companies | Position | End |
|---|---|---|
| BIOGEN INC. | Director/Board Member | 15/05/2022 |
| BIOVERATIV INC | Chairman | 08/03/2018 |
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Training of Brian Posner
Experiences
Positions held
Active
Inactive
Listed companies
Private companies
Connections
88
1st degree connections
20
1st degree companies
Male
Female
Members of the board
Executives
Linked companies
| Private companies | 20 |
|---|---|
Fidelity Management & Research Co. LLC
 Fidelity Management & Research Co. LLC Investment ManagersFinance FMR invests in securities of companies engaged in a variety of economic sectors and industries that are domiciled in the US and outside the US (in developed, emerging and frontier markets); in stocks with growth or value characteristics; and in companies with market capitalizations of all sizes. The firm invests across different asset classes, market sectors, maturities, and regions. | Finance |
Sotheby's Holdings, Inc.
 Sotheby's Holdings, Inc. Specialty StoresRetail Trade Conducts auctions and private sales of fine art and jewelry and provides real estate brokerage services | Retail Trade |
Warburg Pincus Asset Management, Inc.
 Warburg Pincus Asset Management, Inc. Investment ManagersFinance Manages mutual funds | Finance |
Arch Capital Group Ltd.
 Arch Capital Group Ltd. Multi-Line InsuranceFinance Provides property and casualty insurance and reinsurance services | Finance |
Biogen, Inc.
 Biogen, Inc. Pharmaceuticals: MajorHealth Technology Manufactures and markets therapies for neurological and neurodegenerative diseases | Health Technology |
Credit Suisse Asset Management LLC
 Credit Suisse Asset Management LLC Investment ManagersFinance CSAM aims to drive long-term performance and positive impact beyond returns. | Finance |
Hygrove Partners LLC
 Hygrove Partners LLC Investment ManagersFinance Hygrove invests long/short in value stocks that are inexpensive relative to companies' earnings. | Finance |
Anadys Pharmaceuticals, Inc.
 Anadys Pharmaceuticals, Inc. Pharmaceuticals: MajorHealth Technology Develops and manufactures novel small molecule medicines | Health Technology |
BG Medicine, Inc.
 BG Medicine, Inc. Medical SpecialtiesHealth Technology Develops and manufactures diagnostic test kits | Health Technology |
AQR Funds
AQR Funds Investment Trusts/Mutual FundsMiscellaneous Operates as an open-ended investment fund | Miscellaneous |
RiverPark Funds Trust
 RiverPark Funds Trust Investment Trusts/Mutual FundsMiscellaneous Acts as Open-End Investment Fund/Unit Trust | Miscellaneous |
Northwestern University
Northwestern University Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
ClearBridge Investments LLC
 ClearBridge Investments LLC Investment ManagersFinance ClearBridge Investments is a global equity manager that seeks to deliver long-term results through authentic active management by offering investment solutions that emphasize differentiated, bottom-up stock selection. The firm offers strategies focused on three primary client objectives: high active share, income solutions and low volatility. ClearBridge Investments performs research on an ongoing basis for the maintenance of existing investments, and to identify new investment opportunities. They integrate ESG considerations into their fundamental research process across all strategies. | Finance |
Biogen Idec New Ventures, Inc.
 Biogen Idec New Ventures, Inc. Investment ManagersFinance Biogen Idec New Ventures' strategy is to select investments in companies developing innovative human therapeutic products or technologies that will drive product discovery and development more efficiently. Their specific areas of interest are companies in Biogen Idec's current therapeutic areas of neurology, oncology and immunology/inflammation, but they also seek opportunities outside these areas that fit their strategies for longer-term growth. The firm invests at all stages of development; most of their investments are in early-stage companies. They also look for investment opportunities where they can leverage their parent's resources and scientific and development expertise to support these investments. | Finance |
Biogen GmbH
Biogen GmbH Pharmaceuticals: MajorHealth Technology Discovers, develops, manufactures and supplies pharmaceutical products | Health Technology |
Point Rider Group LLC | |
The University of Chicago Booth School of Business
 The University of Chicago Booth School of Business Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
Bioverativ, Inc.
 Bioverativ, Inc. BiotechnologyHealth Technology Operates as a biotechnology company that engages in discovery, research, development and commercialization of therapies for hemophilia & blood disorders | Health Technology |
Dyne Therapeutics, Inc.
 Dyne Therapeutics, Inc. BiotechnologyHealth Technology Develops therapeutics to treat muscle diseases | Health Technology |
Northwestern University Clinical & Translational Sciences Inst
Northwestern University Clinical & Translational Sciences Inst Miscellaneous Commercial ServicesCommercial Services Provides research services to scientific discoveries | Commercial Services |
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