TNDM Institutional Ownership
Who owns Tandem Diabetes Care Inc and what the big funds did with it last quarter, from every SEC 13F filing. 279 funds reported holding TNDM at Jun 30, 2026, together owning 113.7% of the company.
- ●144 buying vs 136 selling
- ●Held by funds +0.4 pts
- ▲Funds holding +3
- ●Superinvestors: 2 added, 2 cut
- ●Put/call not meaningful
What the filings show, not a forecast. Positions can be up to 45 days old and leave out short sales.
Funds holding and ownership
8 quartersQuarter over quarter
all 13F filers| Q2 2026 | This quarter | Q1 2026 | Change |
|---|---|---|---|
| Funds holding | 279 | 276 | +1.1% |
| In funds' top 10 | 1 | 1 | 0.0% |
| 13F shares | 79.1M | 78.8M | +0.4% |
| Held by funds | 113.7% | 113.3% | +0.4 pts |
| New positions | 48 | 40 | +20.0% |
| Increased | 96 | 95 | +1.1% |
| Reduced | 92 | 94 | −2.1% |
| Sold out | 44 | 36 | +22.2% |
| Calls (shares) | 300K | 11K | +2678.7% |
| Puts (shares) | 67K | 94K | −28.7% |
| Put/call ratio | 0.22 | 8.67 | −97.4% |
Buyers vs sellers
adding or new vs cutting or sold outSuperinvestors in TNDM
All superinvestors →
Who owns TNDM
share of fund held shares- Index and passive funds33.4%
- Active managers and hedge funds57.1%
- Banks and brokers8.6%
- Pensions, insurers and other1.0%
The top 10 holders own 49.6% of all TNDM shares that funds reported. Groups are our own grouping of filers by name.
Put/call ratio
funds' options, market makers left outAbove 1 means funds hold more puts than calls, a sign of hedging or bets on a fall. Options are valued at the underlying shares.
Filed so far for Q3 2026
61 funds changed their position- Fideuram Asset Management (Ireland) dacNew+245K sh
- Hussman Strategic Advisors, Inc.New+168K sh
- Y-Intercept (Hong Kong) LtdTrimmed−167K sh
- Mackenzie Financial CorpNew+147K sh
- Inspire Investing, LLCAdded+139K sh
🔒 Free account: see all 20.
Top holders
Q2 2026| # | Fund | Of company | Shares | Value | Change |
|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 16.65% | 11.6M | $175M | +892K |
| 2 | Sessa Capital IM, L.P. | 7.33% | 5.1M | $77M | +369K |
| 3 | Vanguard Portfolio Management LLC | 6.18% | 4.3M | $64.9M | +306K |
| 4 | First Light Asset Management, LLC | 4.86% | 3.4M | $51.1M | +2.1M |
| 5 | Vanguard Capital Management LLC | 4.45% | 3.1M | $46.7M | +58K |
| 6 | State Street Corp | 4.10% | 2.9M | $43M | +189K |
| 7 | GW&K Investment Management, LLC | 3.69% | 2.6M | $38.8M | −120K |
| 8 | Jennison Associates LLC | 3.35% | 2.3M | $35.2M | +673K |
| 9 | Paradice Investment Management LLC | 2.91% | 2M | $30.5M | −18K |
| 10 | Jacobs Levy Equity Management, Inc | 2.88% | 2M | $30.3M | +482K |
- First Light Asset Management, LLC+2.1M sh+$31.2M
- Woodline Partners LP+1.3M sh+$19.7M
- BlackRock, Inc.+892K sh+$13.5M
- Jennison Associates LLC+673K sh+$10.2M
- Qube Research & Technologies Ltd+632K sh+$9.5M
- Verition Fund Management LLC+593K sh+$8.9M
- Millennium Management LLC+550K sh+$8.3M
- Freestone Grove Partners LP+535K sh+$8.1M
- Marshall Wace, LLP−1.4M sh−$27.7M
- ArrowMark Colorado Holdings LLC−1.8M sh−$27.2M
- Baillie Gifford & Co−1.1M sh−$20.9M
- Goldman Sachs Group Inc−1.4M sh−$20.5M
- Two Sigma Investments, LP−1.3M sh−$19.7M
- Defilade Capital Management, L.P.−762K sh−$14.6M
- UBS Group AG−901K sh−$13.6M
- Morgan Stanley−710K sh−$10.7M
TNDM institutional ownership FAQ
Who owns the most TNDM stock?
In Q2 2026 13F filings the largest holder of TNDM was BlackRock, Inc., followed by Sessa Capital IM, L.P. and Vanguard Portfolio Management LLC. Index fund managers are usually the biggest holders of large companies.
What percentage of TNDM is owned by institutions?
Funds that file 13F reports held 113.7% of TNDM's shares at Jun 30, 2026, compared with 113.3% a quarter earlier. That counts every manager with more than $100 million in US stocks.
Are hedge funds buying TNDM?
In Q2 2026, 144 funds bought TNDM (48 of them new positions) and 136 sold (44 sold out completely). Among well known investors, 2 added and 2 cut. Our fund sentiment for TNDM is neutral.
What is TNDM's institutional put/call ratio?
Funds reported $1M of TNDM puts against $4.5M of calls, a put/call ratio of 0.22 (8.67 the quarter before). Market makers and bank trading desks are left out, since their options are mostly hedges.
How current is this TNDM ownership data?
13F filings show holdings at the end of each quarter and are due within 45 days, so positions can be up to six weeks old when they appear. We add each new filing within minutes, and the "filed so far" list shows funds that have already reported the next quarter.
For informational and educational purposes only. Not investment advice, and not a recommendation to buy or sell any security. Fund sentiment summarises what 13F filings show and is not a forecast. Holdings come from SEC Form 13F filings as reported and show positions at the end of the quarter, up to 45 days before the filing. A 13F leaves out short positions, cash, bonds and most foreign holdings. See all hedge fund holdings.