| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| BlackRock, Inc. | 15% | $176,563,735 | 10,106,682 | BlackRock, Inc. | 31 Mar 2025 | |||
| Sessa Capital (Master), L.P. | 6.7% | $78,026,383 | 4,466,307 | Sessa Capital (Master), L.P. | 31 Mar 2025 | |||
| ArrowMark Colorado Holdings LLC | 4.3% | -24% | $62,272,841 | -$17,272,476 | 2,889,691 | -22% | ArrowMark Colorado Holdings, LLC | 31 Dec 2025 |
As of 31 Dec 2025, 264 institutional investors reported holding 74,808,539 shares of TANDEM DIABETES CARE INC - Common Stock, par value $0.001 per share (TNDM). This represents 110% of the company’s total 67,833,122 outstanding shares.
The largest institutional shareholders of TANDEM DIABETES CARE INC - Common Stock, par value $0.001 per share (TNDM) together control 86% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 16% | 11,149,181 | -7.9% | 0% | $245,058,999 |
| VANGUARD GROUP INC | 11% | 7,341,356 | +3.9% | 0% | $161,363,004 |
| Sessa Capital IM, L.P. | 7.4% | 5,000,000 | 0% | 2.2% | $109,900,000 |
| ArrowMark Colorado Holdings LLC | 4.3% | 2,889,691 | -22% | 1.4% | $63,515,408 |
| GW&K Investment Management, LLC | 3.9% | 2,675,157 | -1.7% | 0.51% | $58,800,000 |
| STATE STREET CORP | 3.9% | 2,641,724 | -0.99% | 0% | $58,065,094 |
| CITADEL ADVISORS LLC | 3.1% | 2,088,603 | +5148% | 0.03% | $45,907,494 |
| MORGAN STANLEY | 3.1% | 2,080,497 | +182% | 0% | $45,729,350 |
| Paradice Investment Management LLC | 3.1% | 2,077,745 | -5.4% | 8.9% | $45,668,835 |
| JENNISON ASSOCIATES LLC | 3% | 2,021,376 | +42% | 0.03% | $44,429,844 |
| GOLDMAN SACHS GROUP INC | 2.5% | 1,683,400 | +18% | 0.01% | $37,001,133 |
| JACOBS LEVY EQUITY MANAGEMENT, INC | 2.4% | 1,653,708 | +12% | 0.14% | $36,348,502 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.4% | 1,649,383 | +3.2% | 0% | $36,259,526 |
| Driehaus Capital Management LLC | 2.4% | 1,610,342 | 0.24% | $35,395,317 | |
| Freestone Grove Partners LP | 2.1% | 1,442,836 | -23% | 0.23% | $31,713,535 |
| BNP PARIBAS FINANCIAL MARKETS | 1.8% | 1,248,481 | 0% | 0.02% | $27,441,612 |
| Assenagon Asset Management S.A. | 1.8% | 1,227,856 | 0.04% | $26,988,275 | |
| TWO SIGMA INVESTMENTS, LP | 1.8% | 1,201,527 | +7.5% | 0.04% | $26,409,563 |
| BAILLIE GIFFORD & CO | 1.7% | 1,145,516 | +2.2% | 0.02% | $25,178,442 |
| First Light Asset Management, LLC | 1.6% | 1,089,493 | 1.8% | $23,947,056 | |
| TWO SIGMA ADVISERS, LP | 1.4% | 937,983 | -3.4% | 0.04% | $20,616,866 |
| BARCLAYS PLC | 1.4% | 917,927 | -23% | 0.01% | $20,176,036 |
| MARSHALL WACE, LLP | 1.3% | 875,531 | 0.02% | $19,244,172 | |
| D. E. Shaw & Co., Inc. | 1.3% | 854,266 | -2.6% | 0.01% | $18,776,767 |
| BANK OF AMERICA CORP /DE/ | 1% | 702,503 | +6.7% | 0% | $15,441,016 |
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2025 Q4 | 74,808,539 | $1,644,201,723 | +$38,386,587 | $21.98 | 264 |
| 2025 Q3 | 75,062,169 | $911,087,579 | -$138,652,756 | $12.14 | 251 |
| 2025 Q2 | 80,970,548 | $1,506,919,626 | +$146,515,993 | $18.64 | 269 |
| 2025 Q1 | 73,028,420 | $1,399,471,204 | -$74,262,859 | $19.16 | 271 |
| 2024 Q4 | 72,082,680 | $2,596,593,509 | -$54,203,387 | $36.02 | 311 |
| 2024 Q3 | 73,070,303 | $3,098,544,283 | -$23,063,732 | $42.41 | 326 |
| 2024 Q2 | 73,624,715 | $2,966,330,226 | -$12,633,640 | $40.29 | 315 |
| 2024 Q1 | 74,163,562 | $2,626,695,815 | +$150,901,685 | $35.41 | 290 |
| 2023 Q4 | 70,841,842 | $2,095,507,190 | +$47,113,352 | $29.58 | 264 |
| 2023 Q3 | 69,587,644 | $1,445,242,152 | +$40,169,385 | $20.77 | 224 |
| 2023 Q2 | 67,061,755 | $1,645,737,206 | -$59,226,945 | $24.54 | 242 |
| 2023 Q1 | 68,103,120 | $2,765,613,824 | +$144,781,126 | $40.61 | 270 |
| 2022 Q4 | 64,356,332 | $2,890,283,528 | +$83,553,842 | $44.95 | 290 |
| 2022 Q3 | 62,774,623 | $3,005,075,951 | -$3,660,996 | $47.85 | 279 |
| 2022 Q2 | 61,447,968 | $3,637,020,281 | -$76,699,636 | $59.19 | 317 |
| 2022 Q1 | 59,516,284 | $6,922,056,028 | -$138,240,750 | $116.29 | 365 |
| 2021 Q4 | 60,391,589 | $9,087,447,171 | -$2,104,121 | $150.52 | 376 |
| 2021 Q3 | 61,294,210 | $7,318,019,845 | +$274,585,725 | $119.38 | 331 |
| 2021 Q2 | 59,035,893 | $5,750,025,560 | +$205,481,616 | $97.40 | 295 |
| 2021 Q1 | 57,554,702 | $5,079,400,953 | -$46,897,671 | $88.25 | 282 |
| 2020 Q4 | 58,469,670 | $5,594,436,203 | +$259,885,627 | $95.68 | 295 |
| 2020 Q3 | 54,610,664 | $6,195,906,490 | -$74,521,157 | $113.50 | 317 |
| 2020 Q2 | 55,340,731 | $5,467,195,169 | +$30,463,584 | $98.92 | 298 |
| 2020 Q1 | 55,943,514 | $3,597,678,709 | +$179,201,893 | $64.35 | 272 |
| 2019 Q4 | 54,323,826 | $3,238,388,302 | +$215,522,474 | $59.61 | 277 |
| 2019 Q3 | 49,570,173 | $2,923,699,368 | +$150,187,596 | $58.98 | 265 |
| 2019 Q2 | 46,969,436 | $3,030,219,186 | +$32,868,289 | $64.52 | 257 |
| 2019 Q1 | 46,852,382 | $2,975,069,325 | -$42,975,705 | $63.50 | 259 |
| 2018 Q4 | 47,679,245 | $1,810,642,238 | +$238,092,658 | $37.97 | 197 |
| 2018 Q3 | 41,283,497 | $1,768,571,420 | +$363,867,902 | $42.84 | 180 |
| 2018 Q2 | 33,358,770 | $734,537,970 | +$323,358,099 | $22.02 | 114 |
| 2018 Q1 | 21,326,200 | $105,775,575 | +$86,906,889 | $4.96 | 72 |
| 2017 Q4 | 1,658,886 | $3,911,007 | -$15,365,244 | $2.36 | 29 |
| 2017 Q3 | 8,179,498 | $5,969,000 | +$5,969,000 | $0.73 | 4 |
| 2016 Q2 | 0 | $0 | -$10,000 | $20.87 | 0 |
| 2016 Q1 | 150 | $10,000 | $66.67 | 1 |