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Mirion Technologies
MIR

365 hedge funds and large institutions have $5.91B invested in Mirion Technologies in 2025 Q4 according to their latest regulatory filings, with 82 funds opening new positions, 147 increasing their positions, 94 reducing their positions, and 54 closing their positions.

New
Increased
Maintained
Reduced
Closed

1,114% more call options, than puts

Call options by funds: $206M | Put options by funds: $16.9M

56% more repeat investments, than reductions

Existing positions increased: 147 | Existing positions reduced: 94

52% more first-time investments, than exits

New positions opened: 82 | Existing positions closed: 54

7% more funds holding

Funds holding: 341 → 365 (+24)

0% more funds holding in top 10

Funds holding in top 10: 6 → 6 (0)

0% less capital invested

Capital invested by funds: $5.93B → $5.91B (-$23.7M)

10.14% less ownership

Funds ownership: 111.91% → 101.77% (-10%)

Holders
365
Holders Change
+24
Holders Change %
+7.04%
% of All Funds
4.44%
Holding in Top 10
6
Holding in Top 10 Change
–
Holding in Top 10 Change %
–
% of All Funds
0.07%
New
82
Increased
147
Reduced
94
Closed
54
Calls
$206M
Puts
$16.9M
Net Calls
+$189M
Net Calls Change
+$131M

Top Buyers

1
TG
TCW Group
California
+$61.2M
2
BlackRock
BlackRock
New York
+$44.1M
3
Bank of New York Mellon
Bank of New York Mellon
New York
+$42.8M
4
JP Morgan Chase
JP Morgan Chase
New York
+$35.7M
5
Citadel Advisors
Citadel Advisors
Florida
+$35.7M

Top Sellers

1
T. Rowe Price Investment Management
T. Rowe Price Investment Management
Maryland
-$161M
2
Janus Henderson Group
Janus Henderson Group
United Kingdom
-$76.4M
3
MC
Maverick Capital
Texas
-$60.2M
4
Dimensional Fund Advisors
Dimensional Fund Advisors
Texas
-$52.5M
5
Massachusetts Financial Services
Massachusetts Financial Services
Massachusetts
-$43.1M
Name Holding Trade Value Shares
Change 		Change in
Stake
BlackRock
1
BlackRock
New York
$895M +$44.1M +1,769,477 +5%
Vanguard Group
2
Vanguard Group
Pennsylvania
$711M -$1.8M -71,999 -0.2%
T. Rowe Price Investment Management
3
T. Rowe Price Investment Management
Maryland
$354M -$161M -6,453,787 -30%
State Street
4
State Street
Massachusetts
$215M +$9.54M +382,449 +4%
Fidelity Investments
5
Fidelity Investments
Massachusetts
$197M -$16.6M -664,001 -7%
CLG
6
Cooperman Leon G
$196M – – –
Geode Capital Management
7
Geode Capital Management
Massachusetts
$136M +$3.93M +157,687 +3%
Goldman Sachs
8
Goldman Sachs
New York
$123M +$4.84M +193,914 +4%
UBS Group
9
UBS Group
Switzerland
$114M +$1.39M +55,754 +1%
Janus Henderson Group
10
Janus Henderson Group
United Kingdom
$108M -$76.4M -3,064,988 -40%
Dimensional Fund Advisors
11
Dimensional Fund Advisors
Texas
$96.1M -$52.5M -2,104,375 -34%
Massachusetts Financial Services
12
Massachusetts Financial Services
Massachusetts
$85.8M -$43.1M -1,728,293 -32%
Swedbank
13
Swedbank
Sweden
$79.6M -$15.1M -607,000 -15%
Invesco
14
Invesco
Georgia
$72.6M +$8.58M +344,230 +12%
Bank of New York Mellon
15
Bank of New York Mellon
New York
$72.1M +$42.8M +1,716,020 +126%
TCCM
16
Two Creeks Capital Management
New York
$68.5M -$16.8M -674,961 -19%
Loomis, Sayles & Company
17
Loomis, Sayles & Company
Massachusetts
$66.6M +$2.1M +84,084 +3%
HRCM
18
Hood River Capital Management
Florida
$65.1M +$420K +16,853 +0.6%
American Century Companies
19
American Century Companies
Missouri
$59.9M -$16.8M -672,814 -21%
TG
20
TCW Group
California
$57.4M +$61.2M +2,452,579 New
Charles Schwab
21
Charles Schwab
California
$54.9M +$2.73M +109,614 +5%
Ameriprise
22
Ameriprise
Minnesota
$54.7M +$15.4M +619,118 +36%
Northern Trust
23
Northern Trust
Illinois
$54.6M -$457K -18,340 -0.8%
DCM
24
Driehaus Capital Management
Illinois
$53.8M +$7.76M +311,253 +16%
Royal Bank of Canada
25
Royal Bank of Canada
Ontario, Canada
$50.3M -$4.05M -162,266 -7%
1
2 3 4 5

MIR Hedge Fund Activity: Q4 2025 in Review

365 of the 8,223 institutional investors tracked by Wall St. Rank reported a position in Mirion Technologies (MIR) for Q4 2025, worth a combined $5.91B — down 0.4% from $5.93B a quarter earlier.

Buyers outnumbered sellers: 82 funds opened new MIR positions and 54 closed out — a net gain of 28 holders — while 147 added to existing stakes and 94 trimmed.

The largest buyer was TCW Group, opening a new position worth an estimated $61.2M. The largest seller was T. Rowe Price Investment Management, cutting an estimated $161M.

  • 365 institutional investors held Mirion Technologies (MIR) as of Q4 2025, up from 341 in Q3 2025.
  • Funds reported $5.91B of Mirion Technologies stock for Q4 2025, down 0.4% quarter-over-quarter.
  • 82 funds opened new Mirion Technologies positions in Q4 2025 and 54 closed out, a net change of +28 holders.
  • The largest Mirion Technologies buyer in Q4 2025 was TCW Group, an estimated $61.2M added.
  • The largest Mirion Technologies seller in Q4 2025 was T. Rowe Price Investment Management, an estimated $161M sold.

Based on aggregated 13F filings for Q4 2025.