Tandem Diabetes Care Inc. 13F holders
Of the 44 funds followed here, 6 reported a position in Tandem Diabetes Care Inc. in a 13F for the quarter ended 30 June 2026. The largest: Citadel Advisors, 1.9 million shares worth $28.0 million, 0.0% of its reported book. Sold out: Renaissance Technologies, Baillie Gifford.
| Fund | Shares | Value | Of its book | Change on the quarter | Status | Quarter ended | Filing |
|---|---|---|---|---|---|---|---|
| Citadel Advisors | 1,854,179 | $28.0 million | 0.0% | -422,988 | trimmed | 30 June 2026 | 13F |
| Geode Capital Management | 1,800,797 | $27.2 million | 0.0% | +120,934 | added | 30 June 2026 | 13F |
| Millennium Management | 1,311,739 | $19.8 million | 0.0% | +550,067 | added | 30 June 2026 | 13F |
| FMR LLC | 976,432 | $14.7 million | 0.0% | +262,421 | added | 30 June 2026 | 13F |
| Point72 Asset Management | 910,903 | $13.7 million | 0.0% | +400,425 | added | 30 June 2026 | 13F |
| Two Sigma Investments | 558,409 | $8.4 million | 0.0% | -1,305,785 | trimmed | 30 June 2026 | 13F |
| Renaissance Technologies | 0 | $0 | 0.0% | -58,227 | exited | 30 June 2026 | 13F |
| Baillie Gifford | 0 | $0 | 0.0% | -1,089,393 | exited | 30 June 2026 | 13F |
Value is what the fund reported.
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Change is shares against the fund's previous 13F; a fund with one filing read shows no change. 13Fs cover long US positions of managers above $100 million and are filed up to 45 days after the quarter.Schedule 13D and 13G filed on the name, last twelve months
| Filed | Schedule | Who | Holding | Of the class | Event date | Rule or purpose | Filing |
|---|---|---|---|---|---|---|---|
| 6 August 2026 | 13G/A | Voya Financial, Inc. and 1 other | 149,088 | 0.2% | 30 June 2026 | passive, institutional (13d-1(b)) | EDGAR |
| 5 May 2026 | 13G | Voya Financial, Inc. and 1 other | 4.3 million | 6.3% | 31 March 2026 | passive, institutional (13d-1(b)) | EDGAR |
| 30 April 2026 | 13G | Vanguard Capital Management and 1 other | 3.6 million | 5.2% | 31 March 2026 | passive, institutional (13d-1(b)) | EDGAR |
| 29 April 2026 | 13G | Vanguard Portfolio Management and 1 other | 4.1 million | 5.9% | 31 March 2026 | passive, institutional (13d-1(b)) | EDGAR |
| 27 March 2026 | 13G/A | The Vanguard Group and 1 other | 0 | 0.0% | 13 March 2026 | passive, institutional (13d-1(b)) | EDGAR |
| 17 February 2026 | 13G/A | ArrowMark Colorado Holdings, LLC and 1 other | 2.9 million | 4.3% | 31 December 2025 | passive, institutional (13d-1(b)) | EDGAR |
| 13 November 2025 | 13G | ArrowMark Colorado Holdings, LLC and 1 other | 3.7 million | 5.5% | 30 September 2025 | passive, institutional (13d-1(b)) | EDGAR |
A Schedule 13D is filed by anyone who crosses 5% of a class with intent to influence; a 13G by a passive holder.
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Amendments (/A) report a change, including an exit to zero. Holding and percentage are as the filer stated them on the cover page; the purpose is the filer's own words, cut short.Fails to deliver
| Settlement date | Shares failed | Price | File |
|---|---|---|---|
| 8 September 2026 | 2,362 | $19.90 | SEC |
| 3 September 2026 | 10,367 | $20.56 | SEC |
| 24 August 2026 | 499 | $22.32 | SEC |
| 13 August 2026 | 22,920 | $23.44 | SEC |
Shares that failed to deliver at settlement, per day, from the SEC's half-month files, which arrive about two weeks after the period.
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Largest in the window: 22,920 on 13 August 2026. A fail is an operational fact about settlement, not a position.Source
Each fund's 13F-HR on EDGAR, linked per row; positions matched to TNDM by CUSIP from the SEC's own fails-to-deliver files; Schedule 13D and 13G from the company's own filing index, each read to confirm the company is the issuer named.
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