Tandem Diabetes Care Inc
Ownership
Ownership Structure
Who owns Tandem Diabetes Care Inc (TNDM)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 91.6% of the shares are freely tradable; institutional investors hold 117.8%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 15.37 | 10,690,844 | -4.1 | 03/31/2026 |
| Sessa Capital, L.P | 6.80 | 4,730,757 | -5.4 | 03/31/2026 |
| Vanguard Portfolio Management, LLC | 5.74 | 3,993,333 | +0.0 | 03/31/2026 |
| First Light Asset Management, LLC | 4.86 | 3,383,553 | +157.4 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.37 | 3,038,919 | +0.0 | 03/31/2026 |
| GW&K Investment Management, LLC | 3.86 | 2,689,106 | +0.5 | 03/31/2026 |
| State Street Corp | 3.83 | 2,662,260 | +0.8 | 03/31/2026 |
| Jennison Associates LLC | 3.35 | 2,331,429 | +40.6 | 06/30/2026 |
| Driehaus Capital Management LLC | 3.31 | 2,304,414 | +43.1 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Small-Cap ETF | 6.00 | 4,175,844 | +0.0 | 08/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Sheridan John F | PRESIDENT & CEO | 160,260 | 2,756,472 $ | Aug 15, 2026 | direct |
| Morrison Susan | EVP & Chief Admin. Officer | 52,788 | 907,954 $ | Aug 15, 2026 | direct |
| Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | 52,040 | 895,088 $ | Aug 15, 2026 | direct |
| Carpenter Rick | EVP & Chief Technology Officer | 32,148 | 552,946 $ | Aug 15, 2026 | direct |
| Hansen Shannon Marie | EVP & Chief Legal Officer | 31,650 | 544,380 $ | Aug 15, 2026 | direct |
| Kyrillos Jean-Claude | EVP & Chief Operating Officer | 30,290 | 520,988 $ | Aug 15, 2026 | direct |
| Gasser Elizabeth Anne | EVP, Chief Strategy Officer | 1,396 | 24,011 $ | Aug 15, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Aug 15, 2026 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Other | 942 | 22.72 | 21,402 |
| Aug 15, 2026 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Other | 2,624 | 0.00 | – |
| Aug 15, 2026 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Other | 537 | 22.72 | 12,201 |
| Aug 15, 2026 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Other | 1,496 | 0.00 | – |
| Aug 15, 2026 | Sheridan John F | PRESIDENT & CEO | Other | 5,055 | 22.72 | 114,850 |
| Aug 15, 2026 | Sheridan John F | PRESIDENT & CEO | Other | 9,934 | 0.00 | – |
| Aug 15, 2026 | Sheridan John F | PRESIDENT & CEO | Other | 3,044 | 22.72 | 69,160 |
| Aug 15, 2026 | Sheridan John F | PRESIDENT & CEO | Other | 5,982 | 0.00 | – |
| Aug 15, 2026 | Morrison Susan | EVP & Chief Admin. Officer | Other | 495 | 22.72 | 11,246 |
| Aug 15, 2026 | Morrison Susan | EVP & Chief Admin. Officer | Other | 1,730 | 0.00 | – |
| Aug 15, 2026 | Morrison Susan | EVP & Chief Admin. Officer | Other | 314 | 22.72 | 7,134 |
| Aug 15, 2026 | Morrison Susan | EVP & Chief Admin. Officer | Other | 1,097 | 0.00 | – |
| Aug 15, 2026 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Other | 535 | 22.72 | 12,155 |
| Aug 15, 2026 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Other | 1,010 | 0.00 | – |
| Aug 15, 2026 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Other | 1,029 | 22.72 | 23,379 |
| Aug 15, 2026 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Other | 1,917 | 0.00 | – |
| Aug 15, 2026 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Other | 589 | 22.72 | 13,382 |
| Aug 15, 2026 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Other | 1,097 | 0.00 | – |
| Aug 15, 2026 | Carpenter Rick | EVP & Chief Technology Officer | Other | 820 | 22.72 | 18,630 |
| Aug 15, 2026 | Carpenter Rick | EVP & Chief Technology Officer | Other | 1,610 | 0.00 | – |
| Aug 15, 2026 | Carpenter Rick | EVP & Chief Technology Officer | Other | 457 | 22.72 | 10,383 |
| Aug 15, 2026 | Carpenter Rick | EVP & Chief Technology Officer | Other | 897 | 0.00 | – |
| Aug 15, 2026 | Hansen Shannon Marie | EVP & Chief Legal Officer | Other | 976 | 22.72 | 22,175 |
| Aug 15, 2026 | Hansen Shannon Marie | EVP & Chief Legal Officer | Other | 1,917 | 0.00 | – |
| Aug 15, 2026 | Hansen Shannon Marie | EVP & Chief Legal Officer | Other | 559 | 22.72 | 12,700 |
| Aug 15, 2026 | Hansen Shannon Marie | EVP & Chief Legal Officer | Other | 1,097 | 0.00 | – |
| Jul 15, 2026 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Other | 1,926 | 15.28 | 29,429 |
| Jul 15, 2026 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Other | 3,636 | 0.00 | – |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.