Tandem Diabetes Care (TNDM)
Tandem Diabetes Care on one page: short interest, daily short volume, fails to deliver, planned sales, large holders, 13F holders, financials, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as surgical & medical instruments & apparatus.
15.1M
Short interest
settlement 2026-10-15
6.9
Days to cover
+1.6 days vs prior
56.7%
Short share of volume
2026-11-03
19,965
Fails to deliver
settlement 2026-10-14
Thu 5 Nov
Next earnings
estimated date
-$33K
Insider flow, 90 days
0 buys, 1 sells
As of 2026-11-03.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in TNDM is 15,086,560 shares, up 2,612,175 shares over the last month. Over the last 48 readings it ranged from 5,769,176 shares (15 August 2025) to 15,086,560 shares (15 October 2026). The latest reading sits at the top of that range. At the reported average volume of 2.2M shares a day that is 6.9 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 15,086,560 | +12.8% | 2,198,439 | 6.86 |
| 2026-09-30 | 13,369,091 | +7.2% | 2,548,341 | 5.25 |
| 2026-09-15 | 12,474,385 | +6.1% | 1,580,812 | 7.89 |
| 2026-08-31 | 11,753,819 | +11.0% | 1,438,876 | 8.17 |
| 2026-08-14 | 10,585,732 | -5.8% | 2,723,448 | 3.89 |
| 2026-07-31 | 11,242,544 | -14.3% | 1,708,562 | 6.58 |
| 2026-07-15 | 13,115,208 | +3.0% | 1,501,685 | 8.73 |
| 2026-06-30 | 12,731,073 | +17.3% | 2,264,384 | 5.62 |
| 2026-06-15 | 10,854,250 | -7.9% | 2,664,903 | 4.07 |
| 2026-05-29 | 11,788,786 | +9.1% | 2,837,954 | 4.15 |
| 2026-05-15 | 10,801,432 | +11.1% | 3,219,924 | 3.35 |
| 2026-04-30 | 9,723,853 | +0.8% | 1,575,913 | 6.17 |
| 2026-04-15 | 9,643,357 | -8.4% | 1,489,672 | 6.47 |
| 2026-03-31 | 10,531,890 | -0.1% | 2,083,557 | 5.05 |
| 2026-03-13 | 10,547,769 | +8.0% | 1,759,367 | 6.00 |
| 2026-02-27 | 9,763,559 | +9.0% | 4,262,494 | 2.29 |
| 2026-02-13 | 8,960,466 | +0.3% | 977,059 | 9.17 |
| 2026-01-30 | 8,934,137 | -0.8% | 1,361,781 | 6.56 |
| 2026-01-15 | 9,004,559 | +5.4% | 1,327,740 | 6.78 |
| 2025-12-31 | 8,544,303 | +4.5% | 1,275,718 | 6.70 |
| 2025-12-15 | 8,176,917 | -6.6% | 1,772,136 | 4.61 |
| 2025-11-28 | 8,753,315 | -0.4% | 2,801,803 | 3.12 |
| 2025-11-14 | 8,787,092 | +0.2% | 2,842,224 | 3.09 |
| 2025-10-31 | 8,766,366 | -5.1% | 1,477,802 | 5.93 |
| 2025-10-15 | 9,237,943 | -0.4% | 2,085,204 | 4.43 |
| 2025-09-30 | 9,278,427 | +16.9% | 1,852,962 | 5.01 |
| 2025-09-15 | 7,933,381 | +19.3% | 1,646,250 | 4.82 |
| 2025-08-29 | 6,652,820 | +15.3% | 1,994,896 | 3.33 |
| 2025-08-15 | 5,769,176 | -34.0% | 3,458,636 | 1.67 |
| 2025-07-31 | 8,746,041 | -13.4% | 1,655,156 | 5.28 |
| 2025-07-15 | 10,096,636 | +3.5% | 2,082,206 | 4.85 |
| 2025-06-30 | 9,752,133 | +10.5% | 1,297,697 | 7.51 |
| 2025-06-13 | 8,824,052 | +12.6% | 1,414,976 | 6.24 |
| 2025-05-30 | 7,833,998 | +1.7% | 1,370,704 | 5.72 |
| 2025-05-15 | 7,702,969 | +12.0% | 1,882,431 | 4.09 |
| 2025-04-30 | 6,880,368 | +7.8% | 1,384,581 | 4.97 |
| 2025-04-15 | 6,380,550 | -12.3% | 1,756,093 | 3.63 |
| 2025-03-31 | 7,273,803 | +3.5% | 1,116,448 | 6.52 |
| 2025-03-14 | 7,028,176 | -1.5% | 2,442,243 | 2.88 |
| 2025-02-28 | 7,135,022 | +0.8% | 2,814,459 | 2.54 |
| 2025-02-14 | 7,075,623 | +2.1% | 895,352 | 7.90 |
| 2025-01-31 | 6,930,585 | -3.4% | 947,634 | 7.31 |
| 2025-01-15 | 7,174,309 | +1.2% | 901,793 | 7.96 |
| 2024-12-31 | 7,088,452 | +17.4% | 1,176,654 | 6.02 |
| 2024-12-13 | 6,036,032 | -12.8% | 1,280,826 | 4.71 |
| 2024-11-29 | 6,924,274 | -6.2% | 1,301,674 | 5.32 |
| 2024-11-15 | 7,380,757 | -12.1% | 1,963,442 | 3.76 |
| 2024-10-31 | 8,392,280 | -7.7% | 1,204,204 | 6.97 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 3 November 2026, the short share of TNDM volume is 56.7%, down 16.1 points over the last five sessions. Over the last 30 readings it ranged from 49.6% (7 October 2026) to 89.8% (23 October 2026). The latest reading is 7.2 points below the 30-session average of 63.9%, on 885K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-03 | 502K | 885K | 56.7% | 11 |
| 2026-11-02 | 586K | 1.2M | 49.8% | 773 |
| 2026-10-30 | 301K | 583K | 51.6% | 0 |
| 2026-10-29 | 559K | 1.1M | 51.2% | 18 |
| 2026-10-28 | 665K | 828K | 80.2% | 374 |
| 2026-10-27 | 514K | 706K | 72.9% | 2 |
| 2026-10-26 | 1.0M | 1.6M | 64.9% | 462 |
| 2026-10-23 | 795K | 885K | 89.8% | 415 |
| 2026-10-22 | 753K | 992K | 75.9% | 1,081 |
| 2026-10-21 | 471K | 565K | 83.3% | 0 |
| 2026-10-20 | 251K | 482K | 52.1% | 50 |
| 2026-10-19 | 411K | 534K | 77.0% | 0 |
| 2026-10-16 | 415K | 615K | 67.5% | 0 |
| 2026-10-15 | 444K | 761K | 58.3% | 91 |
| 2026-10-14 | 690K | 907K | 76.0% | 45 |
| 2026-10-13 | 399K | 555K | 71.9% | 567 |
| 2026-10-12 | 349K | 699K | 50.0% | 433 |
| 2026-10-09 | 386K | 629K | 61.5% | 105 |
| 2026-10-08 | 529K | 863K | 61.3% | 50 |
| 2026-10-07 | 395K | 797K | 49.6% | 40,635 |
| 2026-10-06 | 399K | 603K | 66.2% | 361 |
| 2026-10-05 | 381K | 622K | 61.3% | 26 |
| 2026-10-02 | 611K | 935K | 65.3% | 178 |
| 2026-10-01 | 535K | 1.0M | 52.1% | 38,701 |
| 2026-09-30 | 475K | 925K | 51.3% | 0 |
| 2026-09-29 | 535K | 778K | 68.8% | 397 |
| 2026-09-28 | 826K | 1.1M | 73.5% | 1,512 |
| 2026-09-25 | 616K | 1.2M | 51.0% | 17,549 |
| 2026-09-24 | 617K | 1.0M | 60.7% | 110 |
| 2026-09-23 | 877K | 1.3M | 67.0% | 1,323 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 14 October 2026, the fails-to-deliver balance in TNDM is 19,965 shares, down 2,196 shares over the last settlement date. Over the last 30 readings it ranged from 2 shares (22 May 2026) to 63,014 shares (27 May 2026).
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-14 | 19,965 | $16.65 | $332K |
| 2026-10-09 | 22,161 | $15.68 | $347K |
| 2026-10-05 | 7,103 | $16.50 | $117K |
| 2026-09-29 | 16,403 | $16.42 | $269K |
| 2026-09-18 | 376 | $17.23 | $6K |
| 2026-09-16 | 154 | $16.28 | $3K |
| 2026-09-08 | 2,362 | $19.90 | $47K |
| 2026-09-03 | 10,367 | $20.56 | $213K |
| 2026-08-24 | 499 | $22.32 | $11K |
| 2026-08-13 | 22,920 | $23.44 | $537K |
| 2026-07-31 | 400 | $19.01 | $8K |
| 2026-07-22 | 69 | $17.60 | $1K |
| 2026-07-20 | 2,128 | $17.08 | $36K |
| 2026-07-16 | 2,011 | $15.28 | $31K |
| 2026-07-07 | 33,787 | $15.42 | $521K |
| 2026-06-30 | 3 | $15.83 | $47 |
| 2026-06-29 | 45,274 | $16.24 | $735K |
| 2026-06-26 | 19,337 | $15.76 | $305K |
| 2026-06-18 | 12 | $15.40 | $185 |
| 2026-06-16 | 246 | $16.76 | $4K |
| 2026-06-15 | 1,509 | $16.60 | $25K |
| 2026-06-09 | 772 | $18.47 | $14K |
| 2026-06-05 | 62 | $19.45 | $1K |
| 2026-06-02 | 1,791 | $19.12 | $34K |
| 2026-06-01 | 3,061 | $17.20 | $53K |
| 2026-05-28 | 409 | $14.82 | $6K |
| 2026-05-27 | 63,014 | $14.54 | $916K |
| 2026-05-26 | 271 | $14.97 | $4K |
| 2026-05-22 | 2 | $15.76 | $32 |
| 2026-05-20 | 38 | $13.86 | $527 |
Insider trades
SEC Form 4, newest first. JSONInsiders at TNDM reported 1 open-market sell worth $33K in the last 90 days and no open-market buys. Latest filing: TWOMEY CHRISTOPHER J (Director) on 2026-10-27.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-10-27 | TWOMEY CHRISTOPHER J | Director | Sell | 2K | $19.15 | $33K | 24K |
| 2026-10-27 | TWOMEY CHRISTOPHER J | Director | Exercise or conversion | 2K | $19.00 | $32K | 26K |
| 2026-10-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Tax withholding | 2K | $16.52 | $32K | 32K |
| 2026-10-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Exercise or conversion | 4K | $0.00 | $0 | 34K |
| 2026-08-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 942 | $22.72 | $21K | 52K |
| 2026-08-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 3K | $0.00 | $0 | 53K |
| 2026-08-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 537 | $22.72 | $12K | 50K |
| 2026-08-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 1K | $0.00 | $0 | 51K |
| 2026-08-15 | Morrison Susan | EVP & Chief Admin. Officer | Tax withholding | 495 | $22.72 | $11K | 53K |
| 2026-08-15 | Morrison Susan | EVP & Chief Admin. Officer | Exercise or conversion | 2K | $0.00 | $0 | 53K |
| 2026-08-15 | Morrison Susan | EVP & Chief Admin. Officer | Tax withholding | 314 | $22.72 | $7K | 52K |
| 2026-08-15 | Morrison Susan | EVP & Chief Admin. Officer | Exercise or conversion | 1K | $0.00 | $0 | 52K |
| 2026-08-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Tax withholding | 535 | $22.72 | $12K | 30K |
| 2026-08-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Exercise or conversion | 1K | $0.00 | $0 | 31K |
| 2026-08-15 | Sheridan John F | PRESIDENT & CEO | Tax withholding | 5K | $22.72 | $115K | 160K |
| 2026-08-15 | Sheridan John F | PRESIDENT & CEO | Exercise or conversion | 10K | $0.00 | $0 | 165K |
| 2026-08-15 | Sheridan John F | PRESIDENT & CEO | Tax withholding | 3K | $22.72 | $69K | 155K |
| 2026-08-15 | Sheridan John F | PRESIDENT & CEO | Exercise or conversion | 6K | $0.00 | $0 | 158K |
| 2026-08-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Tax withholding | 976 | $22.72 | $22K | 32K |
| 2026-08-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Exercise or conversion | 2K | $0.00 | $0 | 33K |
| 2026-08-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Tax withholding | 559 | $22.72 | $13K | 31K |
| 2026-08-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Exercise or conversion | 1K | $0.00 | $0 | 31K |
| 2026-08-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Tax withholding | 1K | $22.72 | $23K | 1K |
| 2026-08-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Exercise or conversion | 2K | $0.00 | $0 | 2K |
| 2026-08-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Tax withholding | 589 | $22.72 | $13K | 508 |
| 2026-08-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Exercise or conversion | 1K | $0.00 | $0 | 1K |
| 2026-08-15 | Carpenter Rick | EVP & Chief Technology Officer | Tax withholding | 820 | $22.72 | $19K | 32K |
| 2026-08-15 | Carpenter Rick | EVP & Chief Technology Officer | Exercise or conversion | 2K | $0.00 | $0 | 33K |
| 2026-08-15 | Carpenter Rick | EVP & Chief Technology Officer | Tax withholding | 457 | $22.72 | $10K | 31K |
| 2026-08-15 | Carpenter Rick | EVP & Chief Technology Officer | Exercise or conversion | 897 | $0.00 | $0 | 32K |
| 2026-07-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Tax withholding | 2K | $15.28 | $29K | 30K |
| 2026-07-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Exercise or conversion | 4K | $0.00 | $0 | 32K |
| 2026-06-02 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Gift | 7K | $0.00 | $0 | 33K |
| 2026-06-02 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Gift | 7K | $0.00 | $0 | 0 |
| 2026-05-21 | TWOMEY CHRISTOPHER J | Director | Exercise or conversion | 9K | $0.00 | $0 | 24K |
| 2026-05-21 | Sodhi Rajwant | Director | Exercise or conversion | 9K | $0.00 | $0 | 24K |
| 2026-05-21 | ROBERTSON REBECCA B | Director | Exercise or conversion | 9K | $0.00 | $0 | 23K |
| 2026-05-21 | McGroddy-Goetz Kathleen | Director | Exercise or conversion | 9K | $0.00 | $0 | 27K |
| 2026-05-21 | Malagueira Joao Paulo Falcao | Director | Exercise or conversion | 9K | $0.00 | $0 | 22K |
| 2026-05-21 | Howell Peyton R | Director | Exercise or conversion | 9K | $0.00 | $0 | 30K |
| 2026-05-21 | Cha Myoungil | Director | Exercise or conversion | 9K | $0.00 | $0 | 22K |
| 2026-05-21 | Allen Dick | Chair Emeritus | Exercise or conversion | 9K | $0.00 | $0 | 28K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Grant | 1K | $10.90 | $15K | 49K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 4K | $12.82 | $48K | 48K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 10K | $0.00 | $0 | 52K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 537 | $12.82 | $7K | 41K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 1K | $0.00 | $0 | 42K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 540 | $12.82 | $7K | 40K |
| 2026-05-15 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 2K | $0.00 | $0 | 41K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Grant | 1K | $10.90 | $15K | 152K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Tax withholding | 19K | $12.82 | $243K | 151K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Exercise or conversion | 40K | $0.00 | $0 | 170K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Tax withholding | 3K | $12.82 | $39K | 130K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Exercise or conversion | 6K | $0.00 | $0 | 133K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Tax withholding | 3K | $12.82 | $36K | 127K |
| 2026-05-15 | Sheridan John F | PRESIDENT & CEO | Exercise or conversion | 5K | $0.00 | $0 | 130K |
| 2026-05-15 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Tax withholding | 8K | $12.82 | $101K | 40K |
| 2026-05-15 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Exercise or conversion | 10K | $0.00 | $0 | 48K |
| 2026-05-15 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Tax withholding | 57 | $12.82 | $731 | 38K |
| 2026-05-15 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Exercise or conversion | 76 | $0.00 | $0 | 38K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Grant | 1K | $10.90 | $15K | 51K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Tax withholding | 2K | $12.82 | $25K | 49K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Exercise or conversion | 7K | $0.00 | $0 | 51K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Tax withholding | 314 | $12.82 | $4K | 44K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Exercise or conversion | 1K | $0.00 | $0 | 45K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Tax withholding | 430 | $12.82 | $6K | 44K |
| 2026-05-15 | Morrison Susan | EVP & Chief Admin. Officer | Exercise or conversion | 2K | $0.00 | $0 | 44K |
| 2026-05-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Grant | 434 | $10.90 | $5K | 28K |
| 2026-05-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Tax withholding | 2K | $12.82 | $27K | 28K |
| 2026-05-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Exercise or conversion | 4K | $0.00 | $0 | 30K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Grant | 2K | $10.90 | $21K | 30K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Tax withholding | 4K | $12.82 | $50K | 28K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Exercise or conversion | 8K | $0.00 | $0 | 32K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Tax withholding | 559 | $12.82 | $7K | 25K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Exercise or conversion | 1K | $0.00 | $0 | 25K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Tax withholding | 732 | $12.82 | $9K | 24K |
| 2026-05-15 | Hansen Shannon Marie | EVP & Chief Legal Officer | Exercise or conversion | 1K | $0.00 | $0 | 25K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Grant | 1K | $10.90 | $15K | 7K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Tax withholding | 4K | $12.82 | $53K | 6K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Exercise or conversion | 8K | $0.00 | $0 | 10K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Tax withholding | 589 | $12.82 | $8K | 2K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Exercise or conversion | 1K | $0.00 | $0 | 3K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Tax withholding | 807 | $12.82 | $10K | 2K |
| 2026-05-15 | Gasser Elizabeth Anne | EVP, Chief Strategy Officer | Exercise or conversion | 2K | $0.00 | $0 | 3K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Grant | 1K | $10.90 | $15K | 31K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Tax withholding | 3K | $12.82 | $42K | 30K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Exercise or conversion | 6K | $0.00 | $0 | 33K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Tax withholding | 457 | $12.82 | $6K | 26K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Exercise or conversion | 898 | $0.00 | $0 | 27K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Tax withholding | 732 | $12.82 | $9K | 26K |
| 2026-05-15 | Carpenter Rick | EVP & Chief Technology Officer | Exercise or conversion | 1K | $0.00 | $0 | 27K |
| 2026-04-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Tax withholding | 2K | $20.66 | $40K | 26K |
| 2026-04-15 | Kyrillos Jean-Claude | EVP & Chief Operating Officer | Exercise or conversion | 4K | $0.00 | $0 | 28K |
| 2026-03-17 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Sell | 187 | $23.05 | $4K | 38K |
| 2026-03-16 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Tax withholding | 6K | $21.59 | $120K | 38K |
| 2026-03-16 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Exercise or conversion | 7K | $0.00 | $0 | 43K |
| 2026-03-05 | Novara Mark David | EVP & CHIEF COMMERCIAL OFFICER | Sell | 2 | $22.81 | $46 | 36K |
| 2026-02-17 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 616 | $18.95 | $12K | 39K |
| 2026-02-17 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Exercise or conversion | 1K | $0.00 | $0 | 40K |
| 2026-02-17 | Vosseller Leigh | EVP & CHIEF FINANCIAL OFFICER | Tax withholding | 619 | $18.95 | $12K | 39K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Planned sales (Form 144)
Newest first. JSON7 Form 144 notices on file for TNDM worth $55K at the prices reported; 3 in the last 90 days worth $41K. Latest: CHRISTOPHER TWOMEY filed on 2026-10-27 to sell 1,700 shares ($32K) from 2026-10-27.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-10-27 | CHRISTOPHER TWOMEYDirector | 2K | $32K | 0.002% | 2026-10-27 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-09-17 | MARK NOVARAOfficer | 360 | $6K | 0.001% | 2026-09-17 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-08-18 | MARK NOVARAOfficer | 131 | $3K | 0.000% | 2026-08-18 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-06-17 | MARK NOVARAOfficer | 361 | $6K | 0.001% | 2026-06-17 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-05-19 | MARK NOVARAOfficer | 266 | $4K | 0.000% | 2026-05-19 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-03-17 | MARK NOVARAOfficer | 187 | $4K | 0.000% | 2026-03-17 | Morgan Stanley Smith Barney LLC Executive Financial Services |
| 2026-03-05 | MARK NOVARAOfficer | 2 | $47 | 0.000% | 2026-03-05 | Morgan Stanley Smith Barney LLC Executive Financial Services |
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON2 holders report 5% or more of TNDM in their latest filing, all on Schedule 13G (passive). The largest reported stake is Vanguard Portfolio Management at 5.9% of the class (4,052,274 shares), filed 2026-04-29 for an event on 2026-03-31.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-08-06 | 13G/Ano. 1 | Voya Financial, Inc.parent holding company | 149K | 0.2% | 2026-06-30 |
| 2026-04-30 | 13G | Vanguard Capital Managementinvestment adviser | 3.6M | 5.2% | 2026-03-31 |
| 2026-04-29 | 13G | Vanguard Portfolio Managementinvestment adviser | 4.1M | 5.9% | 2026-03-31 |
| 2026-03-27 | 13G/Ano. 8 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
| 2026-02-17 | 13G/Ano. 1 | ArrowMark Colorado Holdings, LLCinvestment adviser | 2.9M | 4.3% | 2025-12-31 |
13F holders
Tracked managers holding TNDM at their latest 13F. JSON6 of the 30 tracked managers held TNDM at their latest 13F, $82.0M in total at quarter-end prices. Citadel Advisors is the largest at $26.2M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 3 added shares and 3 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Citadel Advisors | 2026-06-30 | 1.7M | $26.2M | 0.00% | -457K |
| Millennium Management | 2026-06-30 | 1.3M | $19.8M | 0.01% | +550K |
| D. E. Shaw & Co. | 2026-06-30 | 682K | $10.3M | 0.00% | -102K |
| Point72 Asset Management | 2026-06-30 | 611K | $9.2M | 0.01% | +190K |
| Two Sigma Investments | 2026-06-30 | 558K | $8.4M | 0.01% | -1.3M |
| AQR Capital Management | 2026-06-30 | 534K | $8.1M | 0.00% | +202K |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
Financials
SEC XBRL, as filed. JSONIn Q2 FY 2026 (quarter ended 2026-06-30) Tandem Diabetes Care reported revenue of $254.6M, up 5.8% from the same quarter a year earlier, and net loss of $21.2M (-0.31 diluted EPS). In FY 2025 it generated -$9.7M of operating cash flow. As of 2026-06-30, cash was $62.8M against $602.6M of debt.
- Cash
- $62.8M
- Debt
- $602.6M
- Equity
- $130.4M
- Total assets
- $1.15B
- Shares outstanding
- 69,578,707
Quarterly, last 8 quarters
| Quarter | Period end | Revenue | Net income | Margin | Diluted EPS |
|---|---|---|---|---|---|
| Q2 FY 2026 | 2026-06-30 | $254.6M | -$21.2M | -8.3% | -0.31 |
| Q1 FY 2026 | 2026-03-31 | $247.2M | -$20.4M | -8.2% | -0.30 |
| Q4 FY 2025 | 2025-12-31 | $290.4M | -$589K | -0.2% | -0.01 |
| Q3 FY 2025 | 2025-09-30 | $249.3M | -$21.2M | -8.5% | -0.31 |
| Q2 FY 2025 | 2025-06-30 | $240.7M | -$52.4M | -21.8% | -0.78 |
| Q1 FY 2025 | 2025-03-31 | $234.4M | -$130.6M | -55.7% | -1.97 |
| Q4 FY 2024 | 2024-12-31 | $282.6M | $755K | 0.3% | 0.01 |
| Q3 FY 2024 | 2024-09-30 | $244.0M | -$23.3M | -9.5% | -0.35 |
Fiscal years, with buybacks and dividends
| Fiscal year | Ends | Revenue | Net income | Operating cash flow | Capex | Buybacks | Dividends |
|---|---|---|---|---|---|---|---|
| FY 2025 | 2025-12-31 | $1.01B | -$204.7M | -$9.7M | $19.9M | $0 | n/a |
| FY 2024 | 2024-12-31 | $940.2M | -$96.0M | $24.2M | $19.2M | $30.0M | n/a |
| FY 2023 | 2023-12-31 | $747.7M | -$222.6M | -$31.8M | $26.8M | $0 | n/a |
| FY 2022 | 2022-12-31 | $801.2M | -$94.6M | $50.5M | $34.1M | $0 | n/a |
| FY 2021 | 2021-12-31 | $702.8M | $15.6M | $111.4M | $14.2M | n/a | n/a |
Quarters are the three-month figures the company reports; a fourth quarter marked derived is the fiscal year less the three reported quarters, since companies report it only inside the 10-K. Fiscal years are the annual figures. Buybacks are the cash the company paid to repurchase its common stock in the year, not the amount authorized. Balance sheet lines are as of 2026-06-30; shares outstanding as of 2026-08-03 from the cover page.
What this page is
Tandem Diabetes Care in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Tandem Diabetes Care (TNDM), SEC CIK 1438133, listed on Nasdaq, classified by the SEC as surgical & medical instruments & apparatus. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-03.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-10-14.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-10-27.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-08-06.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Financials
- SEC EDGAR 10-K and 10-Q filingsSource: SEC.Weekly; values are as filed in the 10-Q and 10-K. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-06.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-10-27.JSON and CSV
- Company record
- EDGAR filing index for CIK 1438133Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
Other companies the SEC classifies as surgical & medical instruments & apparatus
Other company pages
Datasets
Frequently Asked Questions
How much of TNDM is sold short?
15,086,560 shares were held short at the 2026-10-15 settlement, 6.9 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is TNDM's daily short volume?
On 2026-11-03, 501,944 of the 884,572 TNDM shares reported to FINRA were sold short, 56.7% of the day's reported volume. Short volume is a flow for one day, not a position.
Does TNDM have fails to deliver?
The SEC's latest file shows 19,965 TNDM shares failed to deliver at settlement 2026-10-14. Fails are reported per settlement date and published twice a month with a lag.
Are TNDM insiders buying or selling?
Insiders at TNDM reported 1 open-market sell worth $33K in the last 90 days and no open-market buys. Latest filing: TWOMEY CHRISTOPHER J (Director) on 2026-10-27.
Have TNDM insiders filed to sell?
7 Form 144 notices on file for TNDM worth $55K at the prices reported; 3 in the last 90 days worth $41K. Latest: CHRISTOPHER TWOMEY filed on 2026-10-27 to sell 1,700 shares ($32K) from 2026-10-27.
Who owns 5% or more of TNDM?
2 holders report 5% or more of TNDM in their latest filing, all on Schedule 13G (passive). The largest reported stake is Vanguard Portfolio Management at 5.9% of the class (4,052,274 shares), filed 2026-04-29 for an event on 2026-03-31.
What did TNDM report last quarter?
In Q2 FY 2026 (quarter ended 2026-06-30) Tandem Diabetes Care reported revenue of $254.6M, up 5.8% from the same quarter a year earlier, and net loss of $21.2M (-0.31 diluted EPS). In FY 2025 it generated -$9.7M of operating cash flow. As of 2026-06-30, cash was $62.8M against $602.6M of debt.
Which tracked 13F managers own TNDM?
6 of the 30 tracked 13F managers held TNDM shares at their latest filing, $82.0M in all. The largest: Ken Griffin's Citadel Advisors (1.7M shares, $26.2M), Izzy Englander's Millennium Management (1.3M shares, $19.8M), D. E. Shaw & Co. (682K shares, $10.3M), Steve Cohen's Point72 Asset Management (611K shares, $9.2M), Two Sigma Investments (558K shares, $8.4M), Cliff Asness's AQR Capital Management (534K shares, $8.1M).
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.