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Tandem Diabetes Care
TNDM

272 hedge funds and large institutions have $1.51B invested in Tandem Diabetes Care in 2026 Q1 according to their latest regulatory filings, with 45 funds opening new positions, 94 increasing their positions, 93 reducing their positions, and 35 closing their positions.

New
Increased
Maintained
Reduced
Closed

1,139% more call options, than puts

Call options by funds: $108M | Put options by funds: $8.7M

29% more first-time investments, than exits

New positions opened: 45 | Existing positions closed: 35

4.68% more ownership

Funds ownership: 110.44% → 115.12% (+4.7%)

1% more funds holding

Funds holding: 268 → 272 (+4)

1% more repeat investments, than reductions

Existing positions increased: 94 | Existing positions reduced: 93

8% less capital invested

Capital invested by funds: $1.65B → $1.51B (-$138M)

67% less funds holding in top 10

Funds holding in top 10: 3 → 1 (-2)

Holders
272
Holders Change
+4
Holders Change %
+1.49%
% of All Funds
3.35%
Holding in Top 10
1
Holding in Top 10 Change
-2
Holding in Top 10 Change %
-66.67%
% of All Funds
0.01%
New
45
Increased
94
Reduced
93
Closed
35
Calls
$108M
Puts
$8.7M
Net Calls
+$99.1M
Net Calls Change
+$41.9M

Top Buyers

1
UBS Group
UBS Group
Switzerland
+$35.4M
2
Wellington Management Group
Wellington Management Group
Massachusetts
+$20.5M
3
SCM
Soleus Capital Management
Connecticut
+$17M
4
DCM
Defilade Capital Management
California
+$16.6M
5
DCM
Driehaus Capital Management
Illinois
+$15.1M

Top Sellers

1
Assenagon Asset Management
Assenagon Asset Management
Luxembourg
-$22.8M
2
BNP Paribas Financial Markets
BNP Paribas Financial Markets
France
-$22.6M
3
Morgan Stanley
Morgan Stanley
New York
-$15.7M
4
Barclays
Barclays
United Kingdom
-$10.8M
5
BlackRock
BlackRock
New York
-$9.96M
Name Holding Trade Value Shares
Change 		Change in
Stake
BlackRock
1
BlackRock
New York
$205M -$9.96M -458,337 -4%
SC
2
Sessa Capital
New York
$90.7M -$5.85M -269,243 -5%
VPM
3
Vanguard Portfolio Management
Pennsylvania
$76.6M +$86.8M +3,993,333 New
ACH
4
ArrowMark Colorado Holdings
Colorado
$59.5M +$4.65M +213,918 +7%
VCM
5
Vanguard Capital Management
Pennsylvania
$58.3M +$66M +3,038,919 New
GKIM
6
GW&K Investment Management
Massachusetts
$51.5M +$303K +13,949 +0.5%
State Street
7
State Street
Massachusetts
$51M +$446K +20,536 +0.8%
DCM
8
Driehaus Capital Management
Illinois
$44.2M +$15.1M +694,072 +43%
Goldman Sachs
9
Goldman Sachs
New York
$42.5M +$11.6M +535,522 +32%
Citadel Advisors
10
Citadel Advisors
Florida
$42M +$2.26M +104,064 +5%
UBS Group
11
UBS Group
Switzerland
$39.3M +$35.4M +1,629,968 +390%
PIM
12
Paradice Investment Management
Colorado
$39.2M -$767K -35,320 -2%
Two Sigma Investments
13
Two Sigma Investments
New York
$35.7M +$14.4M +662,667 +55%
Geode Capital Management
14
Geode Capital Management
Massachusetts
$32.2M +$662K +30,480 +2%
Jennison Associates
15
Jennison Associates
New York
$31.8M -$7.89M -362,928 -18%
Jacobs Levy Equity Management
16
Jacobs Levy Equity Management
New Jersey
$29.2M -$2.82M -129,762 -8%
Marshall Wace
17
Marshall Wace
United Kingdom
$27.7M +$12.3M +566,941 +65%
Morgan Stanley
18
Morgan Stanley
New York
$26M -$15.7M -722,955 -35%
FGP
19
Freestone Grove Partners
California
$25.5M -$2.44M -112,094 -8%
FLAM
20
First Light Asset Management
Minnesota
$25.2M +$4.89M +225,222 +21%
Baillie Gifford & Co
21
Baillie Gifford & Co
United Kingdom
$20.9M -$1.22M -56,123 -5%
Wellington Management Group
22
Wellington Management Group
Massachusetts
$20M +$20.5M +944,455 +961%
VOYA Investment Management
23
VOYA Investment Management
Georgia
$15.4M +$10.5M +484,609 +152%
D.E. Shaw & Co
24
D.E. Shaw & Co
New York
$15M -$1.53M -70,360 -8%
SCM
25
Soleus Capital Management
Connecticut
$15M +$17M +783,000 New
1
2 3 4 5

TNDM Hedge Fund Activity: Q1 2026 in Review

272 of the 8,126 institutional investors tracked by Wall St. Rank reported a position in Tandem Diabetes Care (TNDM) for Q1 2026, worth a combined $1.51B — down 8.4% from $1.65B a quarter earlier.

Buyers outnumbered sellers: 45 funds opened new TNDM positions and 35 closed out — a net gain of 10 holders — while 94 added to existing stakes and 93 trimmed.

The largest buyer was UBS Group, adding an estimated $35.4M. The largest seller was Assenagon Asset Management, cutting an estimated $22.8M.

  • 272 institutional investors held Tandem Diabetes Care (TNDM) as of Q1 2026, up from 268 in Q4 2025.
  • Funds reported $1.51B of Tandem Diabetes Care stock for Q1 2026, down 8.4% quarter-over-quarter.
  • 45 funds opened new Tandem Diabetes Care positions in Q1 2026 and 35 closed out, a net change of +10 holders.
  • The largest Tandem Diabetes Care buyer in Q1 2026 was UBS Group, an estimated $35.4M added.
  • The largest Tandem Diabetes Care seller in Q1 2026 was Assenagon Asset Management, an estimated $22.8M sold.

Based on aggregated 13F filings for Q1 2026.