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Jonathan Siegel
Director/Board Member at
JAGUAR HEALTH, INC.
Net worth: 3 $ as of 2026-06-29
Profile
Jonathan Blair Siegel is the founder of JBS Healthcare Ventures LLC, founded in 2017, where the title held is Chief Executive Officer.
Current jobs include Independent Director at Jaguar Health, Inc. since 2018, Director at Napo Therapeutics SpA since 2021, and Director at Napo Pharmaceuticals, Inc. since 2018.
Former jobs include Chairman & Chief Executive Officer at OPY Acquisition Corp.
I from 2021 to 2023, Associate Director-Pharmaceutical at Bear, Stearns & Co., Inc. from 2003 to 2005, Director at AMAG Pharma USA, Inc. in 2013, Independent Director at Sol-Gel Technologies Ltd., Partner & Head-Healthcare Sector at Kingdon Capital Management LLC from 2011 to 2017, Portfolio Manager at S.A.C.
Capital Advisors LP from 2005 to 2010, Research Associate at Novartis Corp., Research Assistant at Tufts University, Research Associate at Beth Israel Deaconess Medical Center, Inc. from 1994 to 1997, Research Associate-Novartis Center at Harvard Medical School, and Research Associate at Dresdner Kleinwort Wasserstein Group, Inc. Education includes an undergraduate degree from Tufts University conferred in 1995 and an MBA from Columbia Business School conferred in 1999.
Known holdings in public companies
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
| 2026-04-14 | 1 ( 0% ) | 3 $ | 2026-06-29 |
Jonathan Siegel active positions
| Companies | Position | Start |
|---|---|---|
| JAGUAR HEALTH, INC. | Director/Board Member | 2018-03-28 |
Napo Therapeutics SpA
 Napo Therapeutics SpA Pharmaceuticals: MajorHealth Technology Operates as a pharmaceutical company | Director/Board Member | 2021-02-28 |
JBS Healthcare Ventures LLC
 JBS Healthcare Ventures LLC Pharmaceuticals: MajorHealth Technology Develops pharmaceutical solutions to improve healthcare outcomes | Chief Executive Officer | 2017-09-30 |
Napo Pharmaceuticals, Inc.
 Napo Pharmaceuticals, Inc. Pharmaceuticals: MajorHealth Technology Develops and markets human gastrointestinal pharmaceuticals | Director/Board Member | 2018-02-28 |
Former positions of Jonathan Siegel
| Companies | Position | End |
|---|---|---|
| OPY ACQUISITION CORP. I | Chief Executive Officer | 2023-11-30 |
Kingdon Capital Management LLC
 Kingdon Capital Management LLC Investment ManagersFinance Kingdon aims to achieve attractive risk-adjusted returns across all market cycles. The firm adheres to research driven process, investing across geographies, industries and asset classes to find the best use of capital. They offer two investment strategies: a global long/short equity strategy (Flagship Strategy) and a global long/short healthcare strategy (Healthcare Strategy). The Flagship Strategy consists of thematic, idiosyncratic and opportunistic investments with diversified return drivers and an emphasis on liquidity. The Healthcare Strategy primarily invests in the global healthcare industry. | Portfolio Manager-Equities | 2016-12-31 |
S.A.C. Capital Advisors LP
 S.A.C. Capital Advisors LP Investment ManagersFinance S.A.C. Capital Advisors seeks to invest in the stocks of companies with short-term growth catalysts. The firm employs quantitative techniques and merger arbitrage strategies. | Analyst-Equity | 2010-12-30 |
Beth Israel Deaconess Medical Center, Inc.
 Beth Israel Deaconess Medical Center, Inc. Hospital/Nursing ManagementHealth Services Provides healthcare services | Corporate Officer/Principal | 1997-11-30 |
AMAG Pharma USA, Inc.
 AMAG Pharma USA, Inc. Pharmaceuticals: MajorHealth Technology Manufactures pharmaceutical products | Director/Board Member | 2013-10-29 |
Training of Jonathan Siegel
Experiences
Positions held
Active
Inactive
Listed companies
Private companies
Connections
90
1st degree connections
16
1st degree companies
Male
Female
Members of the board
Executives
Linked companies
| Private companies | 16 |
|---|---|
Bear, Stearns & Co., Inc.
 Bear, Stearns & Co., Inc. Investment Banks/BrokersFinance Provides investment banking, securities trading and brokerage Services | Finance |
AMAG Pharma USA, Inc.
AMAG Pharma USA, Inc. Pharmaceuticals: MajorHealth Technology Manufactures pharmaceutical products | Health Technology |
Kingdon Capital Management LLC
Kingdon Capital Management LLC Investment ManagersFinance Kingdon aims to achieve attractive risk-adjusted returns across all market cycles. The firm adheres to research driven process, investing across geographies, industries and asset classes to find the best use of capital. They offer two investment strategies: a global long/short equity strategy (Flagship Strategy) and a global long/short healthcare strategy (Healthcare Strategy). The Flagship Strategy consists of thematic, idiosyncratic and opportunistic investments with diversified return drivers and an emphasis on liquidity. The Healthcare Strategy primarily invests in the global healthcare industry. | Finance |
S.A.C. Capital Advisors LP
S.A.C. Capital Advisors LP Investment ManagersFinance S.A.C. Capital Advisors seeks to invest in the stocks of companies with short-term growth catalysts. The firm employs quantitative techniques and merger arbitrage strategies. | Finance |
Napo Pharmaceuticals, Inc.
Napo Pharmaceuticals, Inc. Pharmaceuticals: MajorHealth Technology Develops and markets human gastrointestinal pharmaceuticals | Health Technology |
Novartis Corp.
 Novartis Corp. Pharmaceuticals: MajorHealth Technology Manufactures pharmacitical products | Health Technology |
Sol-Gel Technologies Ltd.
 Sol-Gel Technologies Ltd. Pharmaceuticals: MajorHealth Technology Engages in the identification, development, and commercialization of topical dermatological drug products for the treatment of skin diseases | Health Technology |
Tufts University
 Tufts University Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
Beth Israel Deaconess Medical Center, Inc.
Beth Israel Deaconess Medical Center, Inc. Hospital/Nursing ManagementHealth Services Provides healthcare services | Health Services |
Harvard Medical School
 Harvard Medical School Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
Dresdner Kleinwort Wasserstein Group, Inc. | |
Columbia Business School
 Columbia Business School Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
Jaguar Health, Inc.
 Jaguar Health, Inc. Pharmaceuticals: MajorHealth Technology Develops pharmaceuticals | Health Technology |
JBS Healthcare Ventures LLC
JBS Healthcare Ventures LLC Pharmaceuticals: MajorHealth Technology Develops pharmaceutical solutions to improve healthcare outcomes | Health Technology |
OPY Acquisition Corp. I
 OPY Acquisition Corp. I Financial ConglomeratesFinance Operates as a blank check company | Finance |
Napo Therapeutics SpA
Napo Therapeutics SpA Pharmaceuticals: MajorHealth Technology Operates as a pharmaceutical company | Health Technology |
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