![Spencer Berthelsen](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>)
Spencer Berthelsen
Director/Board Member at
IONIS PHARMACEUTICALS, INC.
Net worth: 12 M $ as of 2026-05-30
Profile
Spencer R.
Berthelsen is currently Chairman at KS Plan Administrators LLC, Independent Director at Ionis Pharmaceuticals, Inc. since 2002, and Director at St. Luke's Episcopal Hospital.
Formerly, Dr. Berthelsen was Chairman at Kelsey-Seybold Medical Group PLLC from 2011 to 2016, Director at Texas Academy of Internal Medicine in 2005, Director at Caremark National Pharmacy in 2005, Clinical Professor at Baylor College of Medicine from 1999 to 2005, and Professor at The University of Texas Health Science Center at Houston.
Known holdings in public companies
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
| 2026-06-14 | 156,083 ( 0.09% ) | 12 M $ | 2026-05-30 |
Spencer Berthelsen active positions
| Companies | Position | Start |
|---|---|---|
| IONIS PHARMACEUTICALS, INC. | Director/Board Member | 2002-04-30 |
St. Luke's Episcopal Hospital
 St. Luke's Episcopal Hospital Hospital/Nursing ManagementHealth Services Provides medical and health care services | Director/Board Member | - |
KS Plan Administrators LLC
 KS Plan Administrators LLC Life/Health InsuranceFinance Provides health insurance services | Chairman | - |
Former positions of Spencer Berthelsen
| Companies | Position | End |
|---|---|---|
Kelsey-Seybold Medical Group PLLC
 Kelsey-Seybold Medical Group PLLC Medical/Nursing ServicesHealth Services Operates cancer, women's health, ambulatory surgery and sleep centers | Chairman | 2016-03-31 |
Texas Academy of Internal Medicine | Director/Board Member | 2004-12-31 |
Caremark National Pharmacy | Director/Board Member | 2004-12-31 |
The University of Texas Health Science Center at Houston
 The University of Texas Health Science Center at Houston Other Consumer ServicesConsumer Services Functions as a College/University | Corporate Officer/Principal | - |
Baylor College of Medicine
 Baylor College of Medicine Other Consumer ServicesConsumer Services Functions as a College/University | Corporate Officer/Principal | 2004-12-31 |
Experiences
Positions held
Active
Inactive
Listed companies
Private companies
Connections
60
1st degree connections
8
1st degree companies
Male
Female
Members of the board
Executives
Linked companies
| Private companies | 8 |
|---|---|
Ionis Pharmaceuticals, Inc.
 Ionis Pharmaceuticals, Inc. Pharmaceuticals: MajorHealth Technology Discovers and develops antisense drugs | Health Technology |
St. Luke's Episcopal Hospital
St. Luke's Episcopal Hospital Hospital/Nursing ManagementHealth Services Provides medical and health care services | Health Services |
Baylor College of Medicine
Baylor College of Medicine Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
Kelsey-Seybold Medical Group PLLC
Kelsey-Seybold Medical Group PLLC Medical/Nursing ServicesHealth Services Operates cancer, women's health, ambulatory surgery and sleep centers | Health Services |
Texas Academy of Internal Medicine | |
Caremark National Pharmacy | |
KS Plan Administrators LLC
KS Plan Administrators LLC Life/Health InsuranceFinance Provides health insurance services | Finance |
The University of Texas Health Science Center at Houston
The University of Texas Health Science Center at Houston Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
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