Tandem Diabetes Care Inc (TNDM)
Who owns Tandem Diabetes Care Inc (TNDM)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 91.8% of the shares are freely tradable; institutional investors hold 117.8%.
Ownership Structure
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 15.60 | 10,690,844 | -4.1 | 03/31/2026 |
| Vanguard Group Inc | 10.71 | 7,341,356 | +3.9 | 12/31/2025 |
| Sessa Capital, L.P | 6.90 | 4,730,757 | -5.4 | 03/31/2026 |
| Vanguard Portfolio Management, LLC | 5.83 | 3,993,333 | +0.0 | 03/31/2026 |
| ArrowMark Colorado Holdings, LLC (ArrowMark Partners) | 4.53 | 3,103,609 | +7.4 | 03/31/2026 |
| Vanguard Capital Management, LLC | 4.43 | 3,038,919 | +0.0 | 03/31/2026 |
| GW&K Investment Management, LLC | 3.92 | 2,689,106 | +0.5 | 03/31/2026 |
| State Street Corp | 3.88 | 2,662,260 | +0.8 | 03/31/2026 |
| Driehaus Capital Management LLC | 3.36 | 2,304,414 | +43.1 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Small-Cap ETF | 6.00 | 4,111,772 | +0.0 | 05/29/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 15. Jul 2026 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Other | 1,926 | 15.28 | 29,429 |
| 15. Jul 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: July 31, 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.