TANDEM DIABETES CARE INC TNDM
COM NEW · Common Stock · CUSIP 875372203 · ISIN US8753722037
U.S. healthcare company
- SectorHealth care
- IndustrySurgical & Medical Instruments & Apparatus
- HeadquartersSan Diego, CA
- Founded2008
- Websitetandemdiabetes.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($6.0m this quarter). Holder counts are more reliable. Shares outstanding: 66.6m as of 2025-04-25, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $19.17. Options: 10 managers hold calls ($61.6m notional), 7 hold puts ($5.5m).
Trends to Q1 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 298 |
| Q4 2022 | 295 |
| Q1 2023 | 275 |
| Q2 2023 | 248 |
| Q3 2023 | 226 |
| Q4 2023 | 268 |
| Q1 2024 | 291 |
| Q2 2024 | 316 |
| Q3 2024 | 331 |
| Q4 2024 | 315 |
| Q1 2025 | 276 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q2 2023 | 125 | 151 |
| Q3 2023 | 104 | 135 |
| Q4 2023 | 150 | 117 |
| Q1 2024 | 174 | 107 |
| Q2 2024 | 184 | 126 |
| Q3 2024 | 162 | 157 |
| Q4 2024 | 165 | 143 |
| Q1 2025 | 141 | 160 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q2 2024 | $134.9m | $15.3m | 0.11 |
| Q3 2024 | $144.5m | $10.5m | 0.07 |
| Q4 2024 | $113.7m | $7.4m | 0.06 |
| Q1 2025 | $61.6m | $5.5m | 0.09 |
Biggest buyers
| Sessa Capital IM, L.P. | New | +4.5m |
| Hood River Capital Management LLC | Added | +1.0m |
| Balyasny Asset Management L.P. | New | +769.7k |
| GW&K Investment Management, LLC | Added | +740.5k |
| Paradice Investment Management LLC | Added | +693.5k |
| Soleus Capital Management, L.P. | New | +496.0k |
| FMR LLC | Added | +350.2k |
| EDMOND DE ROTHSCHILD HOLDING S.A. | New | +252.6k |
| TUDOR INVESTMENT CORP ET AL | Added | +236.2k |
| ACADIAN ASSET MANAGEMENT LLC | New | +232.9k |
Biggest sellers
| Chicago Capital, LLC | Reduced | -949.9k |
| GILDER GAGNON HOWE & CO LLC | Sold out | -931.9k |
| MARSHALL WACE, LLP | Reduced | -880.5k |
| Bellevue Group AG | Sold out | -782.5k |
| Capital International Investors | Sold out | -718.0k |
| BlackRock, Inc. | Reduced | -669.1k |
| VICTORY CAPITAL MANAGEMENT INC | Reduced | -553.0k |
| OBERWEIS ASSET MANAGEMENT INC/ | Sold out | -506.6k |
| Point72 Asset Management, L.P. | Sold out | -495.3k |
| FRED ALGER MANAGEMENT, LLC | Reduced | -489.1k |
Biggest calls
| UBS Group AG | Unchanged | $52.6m2.7m shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $2.3m121.3k shares |
| WELLS FARGO & COMPANY/MN | New | $1.9m100.0k shares |
| Caption Management, LLC | New | $1.9m100.0k shares |
| SIMPLEX TRADING, LLC | Added | $1.2m64.9k shares |
| JANE STREET GROUP, LLC | Reduced | $607.4k31.7k shares |
| CITADEL ADVISORS LLC | Reduced | $421.5k22.0k shares |
| IMC-Chicago, LLC | Reduced | $398.5k20.8k shares |
| GROUP ONE TRADING LLC | Added | $185.9k9.7k shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Biggest puts
| GROUP ONE TRADING LLC | Added | $2.0m106.3k shares |
| CITADEL ADVISORS LLC | Added | $1.1m56.1k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $1.1m55.9k shares |
| JANE STREET GROUP, LLC | New | $890.9k46.5k shares |
| IMC-Chicago, LLC | Added | $329.6k17.2k shares |
| SIMPLEX TRADING, LLC | Reduced | $63.0k3.3k shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| BlackRock, Inc. 13G · institution filed 2025-04-29 | 15.2% |
| Sessa Capital (Master), L.P. 13G · passive investor new · filed 2025-05-15 | 6.7% |
| VANGUARD PORTFOLIO MANAGEMENT LLC 13G · institution new · filed 2026-04-29 | 5.9% |
| VANGUARD CAPITAL MANAGEMENT LLC 13G · institution new · filed 2026-04-30 | 5.2% |
Fell to 5% or below in the last year: Voya Financial, Inc. (0.2%, 2026-08-06), VANGUARD GROUP INC (0.0%, 2026-03-27; now reported by VANGUARD PORTFOLIO MANAGEMENT LLC), ArrowMark Colorado Holdings LLC (4.3%, 2026-02-17)
Insider purchases and sales in Q1 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q2 2023 | 3 | $484.0k | 0 | — | — |
| Q3 2023 | 1 | $21.4k | 0 | — | — |
| Q4 2023 | 3 | $220.1k | 0 | — | — |
| Q1 2024 | 0 | — | 0 | — | — |
| Q2 2024 | 0 | — | 1 | $258.4k | — |
| Q3 2024 | 0 | — | 0 | — | — |
| Q4 2024 | 1 | $12.4k | 1 | $1.2m | — |
| Q1 2025 | 1 | $190.9k | 0 | — | — |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-03-07 | Kyrillos Jean-Claude EVP & Chief Operating Officer | Bought | $190.9k10.5k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q1 2025
| Manager | Shares | Change |
|---|---|---|
| BlackRock, Inc. 0.00% of their portfolio | 11.0m $211.3m | Reduced -669.1k |
| VANGUARD GROUP INC 0.00% of their portfolio | 7.3m $139.7m | Reduced -147.8k |
| Sessa Capital IM, L.P. 3.53% of their portfolio | 4.5m $85.6m | New |
| GW&K Investment Management, LLC 0.51% of their portfolio | 2.9m $54.9m | Added +740.5k |
| ArrowMark Colorado Holdings LLC 0.84% of their portfolio | 2.7m $52.0m | Reduced -7.4k |
| STATE STREET CORP 0.00% of their portfolio | 2.7m $51.5m | Reduced -77.4k |
| Hood River Capital Management LLC 0.76% of their portfolio | 2.3m $44.3m | Added +1.0m |
| Stephens Investment Management Group LLC 0.47% of their portfolio | 1.7m $32.7m | Added +151.1k |
| Paradice Investment Management LLC 7.06% of their portfolio | 1.6m $31.6m | Added +693.5k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 1.6m $29.8m | Added +23.4k |
| JENNISON ASSOCIATES LLC 0.02% of their portfolio | 1.5m $28.3m | Added +10.8k |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.11% of their portfolio | 1.5m $28.2m | Reduced -189.4k |
| FRED ALGER MANAGEMENT, LLC 0.16% of their portfolio | 1.5m $27.9m | Reduced -489.1k |
| FMR LLC 0.00% of their portfolio | 1.4m $27.5m | Added +350.2k |
| Champlain Investment Partners, LLC 0.19% of their portfolio | 1.4m $26.2m | Reduced -11.0k |
| Park West Asset Management LLC 1.76% of their portfolio | 1.1m $21.5m | Reduced -476.9k |
| MORGAN STANLEY 0.00% of their portfolio | 931.0k $17.8m | Added +83.9k |
| BROWN ADVISORY INC 0.03% of their portfolio | 925.3k $17.7m | Added +12.2k |
| UBS Group AG 0.00% of their portfolio | 835.7k $16.0m | Added +209.3k |
| Balyasny Asset Management L.P. 0.04% of their portfolio | 769.7k $14.7m | New |
| Capital World Investors 0.00% of their portfolio | 767.0k $14.7m | Unchanged |
| BAILLIE GIFFORD & CO 0.01% of their portfolio | 732.6k $14.0m | Reduced -13.5k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 712.6k $13.7m | Added +34.1k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 689.5k $13.2m | Reduced -7.9k |
| TWO SIGMA ADVISERS, LP 0.03% of their portfolio | 679.6k $13.0m | Reduced -202.2k |
| Connor, Clark & Lunn Investment Management Ltd. 0.05% of their portfolio | 645.0k $12.4m | Added +129.9k |
| TWO SIGMA INVESTMENTS, LP 0.03% of their portfolio | 641.4k $12.3m | Reduced -219.7k |
| BROWN CAPITAL MANAGEMENT LLC 0.34% of their portfolio | 591.0k $11.3m | Reduced -51.0k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 570.1k $10.9m | Reduced -32.2k |
| BARCLAYS PLC 0.00% of their portfolio | 514.0k $9.8m | Added +37.0k |
| Soleus Capital Management, L.P. 0.75% of their portfolio | 496.0k $9.5m | New |
| KINGDON CAPITAL MANAGEMENT, L.L.C. 1.97% of their portfolio | 495.2k $9.5m | Reduced -295.3k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 466.7k $8.9m | Added +149.0k |
| BNP PARIBAS FINANCIAL MARKETS 0.01% of their portfolio | 459.8k $8.8m | First filing |
| Bank of New York Mellon Corp 0.00% of their portfolio | 407.5k $7.8m | Reduced -29.2k |
| TUDOR INVESTMENT CORP ET AL 0.07% of their portfolio | 405.3k $7.8m | Added +236.2k |
| PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio | 399.4k $7.7m | Added +11.1k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 387.9k $7.2m | Added +42.2k |
| FRONTIER CAPITAL MANAGEMENT CO LLC 0.08% of their portfolio | 365.2k $7.0m | Added +93.1k |
| Aberdeen Group plc 0.01% of their portfolio | 356.2k $6.8m | Added +107.4k |
| SILVERCREST ASSET MANAGEMENT GROUP LLC 0.05% of their portfolio | 346.1k $6.6m | Reduced -470 |
| ENVESTNET ASSET MANAGEMENT INC 0.00% of their portfolio | 318.5k $6.1m | Added +64.5k |
| Nuveen, LLC 0.00% of their portfolio | 308.3k $5.9m | First filing |
| DAFNA Capital Management LLC 1.60% of their portfolio | 294.2k $5.6m | Added +71.0k |
| RENAISSANCE TECHNOLOGIES LLC 0.01% of their portfolio | 286.1k $5.5m | Reduced -29.6k |
| VOYA INVESTMENT MANAGEMENT LLC 0.00% of their portfolio | 273.4k $5.2m | Added +175.2k |
| EDMOND DE ROTHSCHILD HOLDING S.A. 0.09% of their portfolio | 252.6k $4.8m | New |
| First Light Asset Management, LLC 0.54% of their portfolio | 245.3k $4.7m | Reduced -46.9k |
| Quantinno Capital Management LP 0.03% of their portfolio | 241.8k $4.6m | Added +190.2k |
| Invesco Ltd. 0.00% of their portfolio | 237.1k $4.5m | Added +32.2k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 233.8k $4.5m | Reduced -158.8k |
| ACADIAN ASSET MANAGEMENT LLC 0.01% of their portfolio | 232.9k $4.5m | New |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 227.6k $4.4m | Added +76.2k |
| BEACONLIGHT CAPITAL, LLC 2.88% of their portfolio | 219.8k $4.2m | Reduced -111.5k |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 211.7k $4.1m | Added +49.4k |
| ALGERT GLOBAL LLC 0.10% of their portfolio | 209.3k $4.0m | Added +119.8k |
| Public Sector Pension Investment Board 0.02% of their portfolio | 208.2k $4.0m | Added +44.2k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.01% of their portfolio | 197.8k $3.8m | Reduced -14.4k |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio | 194.0k $3.7m | Added +16.3k |
| KBC Group NV 0.01% of their portfolio | 193.8k $3.7m | Added +1.3k |
| FIL Ltd 0.00% of their portfolio | 192.5k $3.7m | Reduced -8.9k |
| Engineers Gate Manager LP 0.06% of their portfolio | 190.9k $3.7m | Reduced -31.9k |
| KENNEDY CAPITAL MANAGEMENT LLC 0.09% of their portfolio | 187.1k $3.6m | Reduced -80.2k |
| RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio | 186.6k $3.6m | Added +23.0k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.01% of their portfolio | 182.3k $3.5m | Added +152.2k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 180.7k $3.5m | Added +86.9k |
| SECTOR GAMMA AS 1.11% of their portfolio | 180.5k $3.5m | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 178.3k $3.4m | Reduced -432 |
| Legal & General Group Plc 0.00% of their portfolio | 177.0k $3.4m | Reduced -5.7k |
| Divisadero Street Capital Management, LP 0.38% of their portfolio | 174.7k $3.3m | Reduced -185.5k |
| PRUDENTIAL FINANCIAL INC 0.01% of their portfolio | 172.1k $3.8m | Reduced -2.8k |
| iA Global Asset Management Inc. 0.05% of their portfolio | 165.4k $3.2m | New |
| STATE OF WISCONSIN INVESTMENT BOARD 0.01% of their portfolio | 156.2k $3.0m | Added +13.8k |
| Polar Capital Holdings Plc 0.02% of their portfolio | 140.5k $2.7m | Reduced -2.4k |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 139.1k $2.7m | Reduced -151.1k |
| TRUIST FINANCIAL CORP 0.00% of their portfolio | 138.5k $2.7m | Added +19.0k |
| GSA CAPITAL PARTNERS LLP 0.23% of their portfolio | 130.6k $2.5m | New |
| Swiss National Bank 0.00% of their portfolio | 127.3k $2.4m | Reduced -1.4k |
| SEI INVESTMENTS CO 0.00% of their portfolio | 124.4k $2.4m | Added +549 |
| FORMULA GROWTH LTD 0.96% of their portfolio | 123.9k $2.4m | Reduced -2.0k |
| Squarepoint Ops LLC 0.01% of their portfolio | 123.9k $2.4m | Added +60.6k |
| MIZUHO MARKETS AMERICAS LLC 0.05% of their portfolio | 115.8k $2.2m | Added +30.7k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 114.0k $2.2m | Reduced -17.8k |
| RICE HALL JAMES & ASSOCIATES, LLC 0.12% of their portfolio | 105.0k $2.0m | Reduced -526 |
| MOORE CAPITAL MANAGEMENT, LP 0.07% of their portfolio | 104.5k $2.0m | Added +83.5k |
| CITIGROUP INC 0.00% of their portfolio | 101.2k $1.9m | Added +6.0k |
| Universal- Beteiligungs- und Servicegesellschaft mbH 0.00% of their portfolio | 87.8k $1.7m | New |
| JUPITER ASSET MANAGEMENT LTD 0.02% of their portfolio | 87.8k $1.7m | New |
| MANGROVE PARTNERS IM, LLC 0.17% of their portfolio | 82.4k $1.6m | Added +33.7k |
| Orion Portfolio Solutions, LLC 0.01% of their portfolio | 77.2k $2.0m | Added +47.1k |
| Cerity Partners LLC 0.00% of their portfolio | 76.0k $1.5m | Added +18.5k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 74.4k $1.4m | Added +2.1k |
| OPPENHEIMER ASSET MANAGEMENT INC. 0.02% of their portfolio | 72.8k $1.4m | Added +11.0k |
| MARSHALL WACE, LLP 0.00% of their portfolio | 70.4k $1.3m | Reduced -880.5k |
| DARK FOREST CAPITAL MANAGEMENT LP 0.06% of their portfolio | 70.1k $1.3m | New |
| Gotham Asset Management, LLC 0.01% of their portfolio | 68.6k $1.3m | Reduced -47.2k |
| NEW YORK STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 68.2k $1.3m | Unchanged |
| HighTower Advisors, LLC 0.00% of their portfolio | 67.2k $1.3m | Added +57.6k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 66.9k $1.3m | Added +5.7k |
| NATIXIS ADVISORS, LLC 0.00% of their portfolio | 65.6k $1.3m | Reduced -105 |