Tandem Diabetes Care, Inc.
MX ˙ BMV ˙ US8753722037
SecurityMX:TNDM / Tandem Diabetes Care, Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership706,609 shares
Latest Disclosed Value $ 13,545,694
Northern Trust Corp reports 2.16% increase in ownership of TNDM / Tandem Diabetes Care, Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 706,609 shares of Tandem Diabetes Care, Inc. (MX:TNDM) valued at $13,545,694 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 691,693 shares of Tandem Diabetes Care, Inc.. This represents a change in shares of 2.16% during the quarter.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-14 2026-03-31 13F TANDEM DIABETES CARE COM NEW 875372203 706,609 14,916 2.16 13,546 -10.91 0.0004
2026-02-17 2025-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 691,693 810 0.12 15,203 81.27 0.0004
2025-11-14 2025-09-30 13F TANDEM DIABETES CARE COM NEW 875372203 690,883 -9,498 -1.36 8,387 -35.76 0.0011
2025-08-13 2025-06-30 13F TANDEM DIABETES CARE COM NEW 875372203 700,381 10,847 1.57 13,055 -1.18 0.0018
2025-05-13 2025-03-31 13F TANDEM DIABETES CARE COM NEW 875372203 689,534 -7,922 -1.14 13,211 -47.41 0.0020
2025-02-14 2024-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 697,456 61,768 9.72 25,122 -6.81 0.0036
2024-11-13 2024-09-30 13F TANDEM DIABETES CARE COM 875372203 635,688 271,144 74.38 26,960 83.56 0.0044
2024-08-14 2024-06-30 13F TANDEM DIABETES CARE COM 875372203 364,544 22,019 6.43 14,687 21.10 0.0025
2024-05-14 2024-03-31 13F TANDEM DIABETES CARE COM 875372203 342,525 -8,299 -2.37 12,129 16.87 0.0021
2024-02-13 2023-12-31 13F TANDEM DIABETES CARE COM 875372203 350,824 -26,065 -6.92 10,377 32.58 0.0019
2023-11-13 2023-09-30 13F TANDEM DIABETES CARE COM 875372203 376,889 8,012 2.17 7,828 -13.53 0.0015
2023-08-11 2023-06-30 13F TANDEM DIABETES CARE COM 875372203 368,877 4,739 1.30 9,052 -38.78 0.0017
2023-05-15 2023-03-31 13F TANDEM DIABETES CARE COM 875372203 364,138 -232,280 -38.95 14,788 -44.84 0.0029
2023-02-13 2022-12-31 13F TANDEM DIABETES CARE COM 875372203 596,418 -7,619 -1.26 26,809 -7.25 0.0056
2022-11-14 2022-09-30 13F TANDEM DIABETES CARE COM 875372203 604,037 133,290 28.31 28,904 3.74 0.0066
2022-08-12 2022-06-30 13F TANDEM DIABETES CARE COM 875372203 470,747 -13,020 -2.69 27,863 -50.47 0.0060
2022-05-13 2022-03-31 13F TANDEM DIABETES CARE COM 875372203 483,767 -9,176 -1.86 56,257 -24.18 0.0099
2022-02-08 2021-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 492,943 3,388 0.69 74,198 26.96 0.0122
2021-11-15 2021-09-30 13F TANDEM DIABETES CARE COM 875372203 489,555 196,716 67.18 58,442 104.90 0.0103
2021-08-13 2021-06-30 13F TANDEM DIABETES CARE COM NEW 875372203 292,839 -8,481 -2.81 28,522 7.26 0.0050
2021-05-12 2021-03-31 13F TANDEM DIABETES CARE COM NEW 875372203 301,320 6,478 2.20 26,592 -5.74 0.0049
2021-02-11 2020-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 294,842 249 0.08 28,211 -15.63 0.0055
2020-11-16 2020-09-30 13F TANDEM DIABETES CARE COM NEW 875372203 294,593 -846 -0.29 33,436 14.41 0.0073
2020-08-14 2020-06-30 13F TANDEM DIABETES CARE COM 875372203 295,439 -421,102 -58.77 29,225 -36.62 0.0069
2020-05-14 2020-03-31 13F TANDEM DIABETES CARE COM NEW 875372203 716,541 10,810 1.53 46,109 9.61 0.0132
2020-02-14 2019-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 705,731 -20,864 -2.87 42,068 -1.83 0.0094
2019-11-13 2019-09-30 13F TANDEM DIABETES CARE COM 875372203 726,595 54,639 8.13 42,854 -1.16 0.0103
2019-08-13 2019-06-30 13F TANDEM DIABETES CARE COM NEW 875372203 671,956 8,075 1.22 43,355 2.84 0.0103
2019-05-13 2019-03-31 13F TANDEM DIABETES CARE COM NEW 875372203 663,881 1,961 0.30 42,156 67.73 0.0104
2019-02-12 2018-12-31 13F TANDEM DIABETES CARE COM NEW 875372203 661,920 20,714 3.23 25,133 -8.51 0.0070
2018-11-14 2018-09-30 13F TANDEM DIABETES CARE COM NEW 875372203 641,206 108,145 20.29 27,470 134.01 0.0067
2018-09-18 2018-06-30 13F/A-1 TANDEM DIABETES CARE COM NEW 875372203 533,061 449,314 536.51 11,739 2,728.67 0.0030
2018-08-14 2018-06-30 13F TANDEM DIABETES CARE COM 875372203 513,734 429,987 11,313
2018-05-09 2018-03-31 13F TANDEM DIABETES CARE COM 875372203 83,747 83,747 415 0.0001
2018-02-14 2017-12-31 13F TANDEM DIABETES CARE COM 875372104 0 -50,678 -100.00 0 -100.00
2017-11-13 2017-09-30 13F TANDEM DIABETES CARE COM 875372104 50,678 17,344 52.03 37 42.31 0.0000
2017-08-11 2017-06-30 13F TANDEM DIABETES CARE COM 875372104 33,334 -160,996 -82.85 26 -88.89 0.0000
2017-05-12 2017-03-31 13F TANDEM DIABETES CARE COM 875372104 194,330 -15,498 -7.39 234 -48.12 0.0001
2017-02-13 2016-12-31 13F TANDEM DIABETES CARE COM 875372104 209,828 -887 -0.42 451 -72.06 0.0001
2016-11-09 2016-09-30 13F TANDEM DIABETES CARE COM 875372104 210,715 -11,295 -5.09 1,614 -3.58 0.0005
2016-08-12 2016-06-30 13F TANDEM DIABETES CARE COM 875372104 222,010 12,268 5.85 1,674 -8.32 0.0005
2016-08-19 2016-03-31 13F/A-1 TANDEM DIABETES CARE COM 875372104 209,742 2,929 1.42 1,826 -25.23 0.0006
2016-05-13 2016-03-31 13F TANDEM DIABETES CARE COM 875372104 209,742 1,826
2016-02-12 2015-12-31 13F TANDEM DIABETES CARE COM 875372104 206,813 20,200 10.82 2,442 48.54 0.0008
2015-11-12 2015-09-30 13F TANDEM DIABETES CARE COM 875372104 186,613 186,613 0.00 1,644 0.0005
2015-08-13 2015-06-30 13F TANDEM DIABETES CARE COM 875372104 0 -105,431 -100.00 0 -100.00
2015-05-14 2015-03-31 13F TANDEM DIABETES CARE COM 875372104 105,431 9,904 10.37 1,331 9.73 0.0004
2015-02-12 2014-12-31 13F TANDEM DIABETES CARE COM 875372104 95,527 -299 -0.31 1,213 -5.75 0.0004
2014-11-13 2014-09-30 13F TANDEM DIABETES CARE COM 875372104 95,826 27 0.03 1,287 -17.39 0.0004
2014-08-14 2014-06-30 13F TANDEM DIABETES CARE COM 875372104 95,799 -14,868 -13.43 1,558 -36.28 0.0005
2014-05-14 2014-03-31 13F TANDEM DIABETES CARE COM 875372104 110,667 -11,218 -9.20 2,445 -22.16 0.0008
2014-02-21 2013-12-31 13F/A-1 TANDEM DIABETES CARE COM 875372104 121,885 121,885 3,141 0.0010
2014-02-12 2013-12-31 13F TANDEM DIABETES CARE COM 875372104 121,885 3,141 0.0010
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.