Tandem Diabetes Care
TNDM
255 hedge funds and large institutions have $911M invested in Tandem Diabetes Care in 2025 Q3 according to their latest regulatory filings, with 43 funds opening new positions, 75 increasing their positions, 97 reducing their positions, and 57 closing their positions.
470% more call options, than puts
Call options by funds: $36.7M | Put options by funds: $6.44M
6% less funds holding
Funds holding: 270 → 255 (-15)
10.46% less ownership
Funds ownership: 121.58% → 111.12% (-10%)
23% less repeat investments, than reductions
Existing positions increased: 75 | Existing positions reduced: 97
25% less first-time investments, than exits
New positions opened: 43 | Existing positions closed: 57
40% less capital invested
Capital invested by funds: $1.51B → $911M (-$596M)
50% less funds holding in top 10
Funds holding in top 10: 2 → 1 (-1)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
FGP
Freestone Grove Partners
San Francisco,
California
|
+$25.3M |
| 2 |
BlackRock
New York
|
+$16.6M |
| 3 |
ACH
ArrowMark Colorado Holdings
Denver,
Colorado
|
+$13.4M |
| 4 |
Barclays
London,
United Kingdom
|
+$8.43M |
| 5 |
Acadian Asset Management
Boston,
Massachusetts
|
+$7.58M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
SIMG
Stephens Investment Management Group
Houston,
Texas
|
-$32.4M |
| 2 |
CIP
Champlain Investment Partners
Burlington,
Vermont
|
-$27.1M |
| 3 |
OAM
Ophir Asset Management
Sydney,
Australia
|
-$24.4M |
| 4 |
Brown Advisory
Baltimore,
Maryland
|
-$19.7M |
| 5 |
Capital World Investors
Los Angeles,
California
|
-$14.3M |
TNDM Hedge Fund Activity: Q3 2025 in Review
255 of the 7,621 institutional investors tracked by Wall St. Rank reported a position in Tandem Diabetes Care (TNDM) for Q3 2025, worth a combined $911M — down 40% from $1.51B a quarter earlier.
Sellers outnumbered buyers: 57 funds closed out of TNDM and 43 opened new positions — a net loss of 14 holders — while 97 trimmed existing stakes and 75 added.
The largest buyer was Freestone Grove Partners, opening a new position worth an estimated $25.3M. The largest seller was Stephens Investment Management Group, exiting entirely with an estimated $32.4M sold.
- 255 institutional investors held Tandem Diabetes Care (TNDM) as of Q3 2025, down from 270 in Q2 2025.
- Funds reported $911M of Tandem Diabetes Care stock for Q3 2025, down 40% quarter-over-quarter.
- 43 funds opened new Tandem Diabetes Care positions in Q3 2025 and 57 closed out, a net change of -14 holders.
- The largest Tandem Diabetes Care buyer in Q3 2025 was Freestone Grove Partners, an estimated $25.3M added.
- The largest Tandem Diabetes Care seller in Q3 2025 was Stephens Investment Management Group, an estimated $32.4M sold.
Based on aggregated 13F filings for Q3 2025.