Ranked by reported Q2 2026 13F market value
Share of total reported institutional value in TNDM held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 11.6M | $174.8M | +8.3% | 16.902% | 0.00% |
| 2 | UBS Group AG | 6.3M | $95.4M | -12.5% | 9.230% | 0.01% |
| 3 | Sessa Capital IM, L.P. | 5.1M | $77.0M | +7.8% | 7.442% | 1.29% |
| 4 | VANGUARD PORTFOLIO MANAGEMENT LLC | 4.3M | $64.9M | +7.7% | 6.274% | 0.00% |
| 5 | First Light Asset Management, LLC | 3.4M | $51.1M | +157.4% | 4.937% | 3.10% |
| 6 | VANGUARD CAPITAL MANAGEMENT LLC | 3.1M | $46.7M | +1.9% | 4.519% | 0.00% |
| 7 | STATE STREET CORP | 2.9M | $43.0M | +7.1% | 4.161% | 0.00% |
| 8 | JENNISON ASSOCIATES LLC | 2.3M | $35.2M | +40.6% | 3.402% | 0.02% |
| 9 | Paradice Investment Management LLC | 2.0M | $30.5M | -0.9% | 2.954% | 4.87% |
| 10 | JACOBS LEVY EQUITY MANAGEMENT, INC | 2.0M | $30.3M | +31.7% | 2.928% | 0.11% |
| 11 | Freestone Grove Partners LP | 1.9M | $28.2M | +40.2% | 2.723% | 0.18% |
| 12 | CITADEL ADVISORS LLC | 1.9M | $28.0M | -18.6% | 2.706% | 0.00% |
| 13 | GEODE CAPITAL MANAGEMENT, LLC | 1.8M | $27.2M | +7.2% | 2.628% | 0.00% |
| 14 | DRIEHAUS CAPITAL MANAGEMENT LLC | 1.8M | $27.0M | -22.4% | 2.608% | 0.16% |
| 15 | MILLENNIUM MANAGEMENT LLC | 1.3M | $19.8M | +72.2% | 1.914% | 0.01% |
| 16 | Woodline Partners LP | 1.3M | $19.7M | — | 1.908% | 0.06% |
| 17 | ArrowMark Colorado Holdings LLC | 1.3M | $19.6M | -58.1% | 1.896% | 0.82% |
| 18 | FMR LLC | 976K | $14.7M | +36.8% | 1.425% | 0.00% |
| 19 | Point72 Asset Management, L.P. | 911K | $13.7M | +78.4% | 1.329% | 0.02% |
| 20 | ROYCE & ASSOCIATES LP | 901K | $13.6M | +29.3% | 1.314% | 0.11% |
| 21 | WELLINGTON MANAGEMENT GROUP LLP | 872K | $13.2M | -16.4% | 1.272% | 0.00% |
| 22 | GOLDMAN SACHS GROUP INC | 862K | $13.0M | -61.1% | 1.258% | 0.00% |
| 23 | NORTHERN TRUST CORP | 754K | $11.4M | +6.7% | 1.100% | 0.00% |
| 24 | Verition Fund Management LLC | 700K | $10.6M | +553.5% | 1.022% | 0.03% |
| 25 | ExodusPoint Capital Management, LP | 692K | $10.4M | +9.3% | 1.010% | 0.07% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in TNDM — a direct measure of their conviction.
Filings activity in TNDM during Q2 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q2 2026 | 275 | +0.4% | 124.03% | 1.08 pp | $1.23B | 21% |
| Q1 2026 | 274 | +3.0% | 125.11% | +9.13 pp | $1.55B | 4.7% |
| Q4 2025 | 266 | +6.0% | 115.98% | 1.03 pp | $1.63B | +83% |
| Q3 2025 | 251 | 5.3% | 117.01% | 8.08 pp | $894M | 38% |
| Q2 2025 | 265 | 1.1% | 125.09% | +9.51 pp | $1.45B | +6.4% |
| Q1 2025 | 268 | 14% | 115.58% | +6.02 pp | $1.36B | 53% |
| Q4 2024 | 312 | 3.4% | 109.56% | 1.14 pp | $2.90B | 0.0% |
| Q3 2024 | 323 | — | 110.70% | — | $2.90B | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying TNDM stock.
Based on Q2 2026 13F filings, institutional ownership of Tandem Diabetes Care, Inc. stands at 124.0%, held across 275 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of TNDM, with approximately 11,583,125 shares worth $0.17B as of Q2 2026.
Yes — 3 widely-followed marquee investors appear among the top 25 institutional holders of TNDM, including CITADEL ADVISORS LLC, MILLENNIUM MANAGEMENT LLC, Point72 Asset Management, L.P..
Our composite Smart Money Score for TNDM is 51 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
45 institutions opened new positions in TNDM during Q2 2026, while 44 fully exited. 52 added to existing positions and 173 trimmed.
TNDM institutional ownership fell by 1.08 percentage points quarter-over-quarter, with a net change of +1 holders.
The top 10 institutions account for 52.6% of all reported 13F value in TNDM, and the top 25 account for 74.4%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Tandem Diabetes Care, Inc. (TNDM) Institutional Ownership