![Stephen Mayo](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>)
Stephen Mayo
Director/Board Member at
MERCK & CO., INC.
Net worth: 399 931 $ as of 2026-05-30
Profile
Stephen L.
Mayo is the founder of Xencor, Inc., founded in 1997.
Dr. Mayo is also the founder of Molecular Simulations, Inc.,Protabit LLC..
Dr. Mayo currently serves as an Independent Director at Merck & Co., Inc. since 2021, an Independent Director at Sarepta Therapeutics, Inc. since 2021, a Director at MSD Pharma (Singapore) Pte Ltd. since 2021, an Independent Director at Allogene Therapeutics, Inc. since 2022, and a Professor at California Institute of Technology since 2020.
Former positions include Director at the American Association for the Advancement of Science from 2010 to 2014 and Director at The National Science Foundation from 2013 to 2018.
Education includes a doctorate from California Institute of Technology conferred in 1987 and an undergraduate degree from The Pennsylvania State University conferred in 1983.
Known holdings in public companies
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
| 2026-06-03 | 18,640 ( 0.02% ) | 333 097 $ | 2026-05-30 | |
| 2026-03-30 | 25,328 ( 0.01% ) | 54 962 $ | 2026-05-30 | |
| 2026-05-28 | 100 ( 0% ) | 11 872 $ | 2026-05-30 |
Stephen Mayo active positions
| Companies | Position | Start |
|---|---|---|
| MERCK & CO., INC. | Director/Board Member | 2021-03-14 |
| SAREPTA THERAPEUTICS, INC. | Director/Board Member | 2021-11-15 |
| ALLOGENE THERAPEUTICS, INC. | Director/Board Member | 2022-07-11 |
California Institute of Technology
 California Institute of Technology Other Consumer ServicesConsumer Services Functions as a College/University | Corporate Officer/Principal | 2006-12-31 |
MSD Pharma (Singapore) Pte Ltd.
 MSD Pharma (Singapore) Pte Ltd. Medical DistributorsDistribution Services Wholesales pharmaceuticals | Director/Board Member | 2020-12-31 |
Former positions of Stephen Mayo
| Companies | Position | End |
|---|---|---|
The National Science Foundation
 The National Science Foundation Miscellaneous Commercial ServicesCommercial Services Supports fundamental science and engineering researches | Director/Board Member | 2017-12-31 |
American Association for the Advancement of Science
 American Association for the Advancement of Science Miscellaneous Commercial ServicesCommercial Services Provides science related journal, program, and education services | Director/Board Member | 2013-12-31 |
Molecular Simulations, Inc.
 Molecular Simulations, Inc. Packaged SoftwareTechnology Services Provider of predictive modeling software | Founder | - |
Protabit LLC
 Protabit LLC Packaged SoftwareTechnology Services Operates as a computational protein design software platform | Founder | - |
| ░░░░░░░ ░░░░ | ░░░░░░░ | - |
Training of Stephen Mayo
Experiences
Positions held
Active
Inactive
Listed companies
Private companies
Connections
84
1st degree connections
11
1st degree companies
Male
Female
Members of the board
Executives
Linked companies
| Private companies | 11 |
|---|---|
Merck & Co., Inc.
 Merck & Co., Inc. Pharmaceuticals: MajorHealth Technology Manufactures human and animal health pharmaceutical products & vaccines | Health Technology |
Sarepta Therapeutics, Inc.
 Sarepta Therapeutics, Inc. Pharmaceuticals: MajorHealth Technology Manufactures micro-dystrophin gene therapy | Health Technology |
Molecular Simulations, Inc.
Molecular Simulations, Inc. Packaged SoftwareTechnology Services Provider of predictive modeling software | Technology Services |
Xencor, Inc.
 Xencor, Inc. BiotechnologyHealth Technology Develops therapeutics to treat autoimmune and allergic diseases, cancer and other conditions | Health Technology |
California Institute of Technology
California Institute of Technology Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
The Pennsylvania State University
 The Pennsylvania State University Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
American Association for the Advancement of Science
American Association for the Advancement of Science Miscellaneous Commercial ServicesCommercial Services Provides science related journal, program, and education services | Commercial Services |
The National Science Foundation
The National Science Foundation Miscellaneous Commercial ServicesCommercial Services Supports fundamental science and engineering researches | Commercial Services |
MSD Pharma (Singapore) Pte Ltd.
MSD Pharma (Singapore) Pte Ltd. Medical DistributorsDistribution Services Wholesales pharmaceuticals | Distribution Services |
Allogene Therapeutics, Inc.
 Allogene Therapeutics, Inc. BiotechnologyHealth Technology Operates as a clinical stage immuno-oncology | Health Technology |
Protabit LLC
Protabit LLC Packaged SoftwareTechnology Services Operates as a computational protein design software platform | Technology Services |
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