MIRION TECHNOLOGIES INC (MIR) Top Institutional Shareholders
MIRION TECHNOLOGIES INC (MIR) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $4.29B in MIR holdings during the latest filing period.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of MIR tracked by InsiderSet, reporting ownership valued at approximately $703.77M in its March 31, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $668.19M, representing an estimated loss of -5.06% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 49% of the total disclosed MIR value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Vanguard Portfolio Management Llc, Vanguard Capital Management Llc, and several other long-term asset managers with concentrated positions in MIRION TECHNOLOGIES INC (MIR).
This page ranks the largest institutional MIR shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
351
Total Reported Value
$4.29B
Largest Holder
Blackrock, Inc.
Largest Position
$703.77M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
59
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.01% | 37,857,697 | $703,774,594 | $668,188,352 | -$35,586,242 | -5.06% | |
| Vanguard Portfolio Management Llc | 0.02% | 17,905,722 | $332,867,372 | $316,035,993 | -$16,831,379 | -5.06% | |
| Vanguard Capital Management Llc | 0.00% | 10,505,195 | $195,291,575 | $185,416,692 | -$9,874,883 | -5.06% | |
| State Street Corp | 0.01% | 9,430,017 | $175,304,016 | $166,439,800 | -$8,864,216 | -5.06% | |
| Cooperman Leon G | 5.11% | 8,383,441 | $155,848,168 | $147,967,734 | -$7,880,434 | -5.06% | |
| Goldman Sachs Group Inc | 0.02% | 7,349,668 | $136,630,327 | $129,721,640 | -$6,908,687 | -5.06% | |
| Fmr Llc | 0.01% | 6,551,692 | $121,795,956 | $115,637,364 | -$6,158,592 | -5.06% | |
| Geode Capital Management, Llc | 0.01% | 5,940,175 | $110,449,172 | $104,844,089 | -$5,605,083 | -5.07% | |
| Millennium Management Llc | 0.07% | 5,106,801 | $94,935,431 | $90,135,038 | -$4,800,393 | -5.06% | |
| Dimensional Fund Advisors Lp | 0.02% | 4,694,288 | $87,240,303 | $82,854,183 | -$4,386,120 | -5.03% | |
| Bank Of New York Mellon Corp | 0.02% | 4,536,732 | $84,337,841 | $80,073,320 | -$4,264,521 | -5.06% | |
| Janus Henderson Group Plc | 0.04% | 4,043,089 | $75,163,723 | $71,360,521 | -$3,803,202 | -5.06% | |
| Ubs Group Ag | 0.01% | 3,766,842 | $70,025,592 | $66,484,761 | -$3,540,831 | -5.06% | |
| Swedbank Ab | 0.06% | 3,159,950 | $58,743,471 | $55,773,117 | -$2,970,354 | -5.06% | |
| American Century Companies Inc | 0.03% | 2,732,762 | $50,802,086 | $48,233,249 | -$2,568,837 | -5.06% | |
| Alyeska Investment Group, L.P. | 0.14% | 2,701,580 | $50,222,372 | $47,682,887 | -$2,539,485 | -5.06% | |
| Loomis Sayles & Co L P | 0.07% | 2,670,228 | $49,639,539 | $47,129,524 | -$2,510,015 | -5.06% | |
| Maverick Capital Ltd | 0.57% | 2,649,879 | $49,261,251 | $46,770,364 | -$2,490,887 | -5.06% | |
| Two Creeks Capital Management, Lp | 4.81% | 2,449,059 | $45,528,007 | $43,225,891 | -$2,302,116 | -5.06% | |
| Northern Trust Corp | 0.01% | 2,366,237 | $43,988,346 | $41,764,083 | -$2,224,263 | -5.06% | |
| Invesco Ltd. | 0.01% | 2,294,250 | $42,650,108 | $40,493,513 | -$2,156,596 | -5.06% | |
| Morgan Stanley | 0.00% | 2,285,068 | $42,479,436 | $40,331,450 | -$2,147,986 | -5.06% | |
| Charles Schwab Investment Management Inc | 0.01% | 2,277,245 | $42,333,985 | $40,193,374 | -$2,140,611 | -5.06% | |
| Alliancebernstein L.P. | 0.01% | 1,653,429 | $38,723,307 | $29,183,022 | -$9,540,285 | -24.64% | |
| Franklin Resources Inc | 0.01% | 1,996,144 | $37,108,320 | $35,231,942 | -$1,876,378 | -5.06% | |
| Royal Bank Of Canada | 0.01% | 1,961,404 | $36,462,000 | $34,618,781 | -$1,843,219 | -5.06% | |
| Nuveen, Llc | 0.01% | 1,949,992 | $36,250,352 | $34,417,359 | -$1,832,993 | -5.06% | |
| Conestoga Capital Advisors, Llc | 0.68% | 1,831,019 | $34,038,643 | $32,317,485 | -$1,721,158 | -5.06% | |
| Citadel Advisors Llc | 0.02% | 1,823,252 | $33,894,255 | $32,180,398 | -$1,713,857 | -5.06% | |
| Vanguard Fiduciary Trust Co | 0.01% | 1,694,538 | $31,501,461 | $29,908,596 | -$1,592,865 | -5.06% | |
| Chescapmanager Llc | 4.93% | 1,659,137 | $30,843,357 | $29,283,768 | -$1,559,589 | -5.06% | |
| Massachusetts Financial Services Co | 0.01% | 1,589,259 | $29,544,325 | $28,050,421 | -$1,493,904 | -5.06% | |
| Troluce Capital Advisors Llc | 2.95% | 1,500,000 | $27,885,000 | $26,475,000 | -$1,410,000 | -5.06% | |
| Rockefeller Capital Management L.P. | 0.05% | 1,392,724 | $25,890,739 | $24,581,579 | -$1,309,160 | -5.06% | |
| Emerald Advisers, Llc | 0.81% | 1,381,574 | $25,683,461 | $24,384,781 | -$1,298,680 | -5.06% | |
| Stephens Investment Management Group Llc | 0.35% | 1,374,876 | $25,558,945 | $24,266,561 | -$1,292,384 | -5.06% | |
| Bank Of America Corp | 0.00% | 1,355,298 | $25,194,990 | $23,921,010 | -$1,273,980 | -5.06% | |
| Segall Bryant & Hamill, Llc | 0.40% | 1,131,552 | $24,452,839 | $19,971,893 | -$4,480,946 | -18.32% | |
| Davidson Kempner Capital Management Lp | 0.53% | 1,314,819 | $24,442,485 | $23,206,555 | -$1,235,930 | -5.06% | |
| Brown Advisory Inc | 0.04% | 1,300,073 | $24,168,354 | $22,946,288 | -$1,222,066 | -5.06% | |
| Timessquare Capital Management, Llc | 0.41% | 1,294,165 | $24,058,527 | $22,842,012 | -$1,216,515 | -5.06% | |
| Ameriprise Financial Inc | 0.01% | 1,289,690 | $23,975,337 | $22,763,029 | -$1,212,309 | -5.06% | |
| Daiwa Securities Group Inc. | 0.07% | 1,217,497 | $22,633,269 | $21,488,822 | -$1,144,447 | -5.06% | |
| Bamco Inc | 0.07% | 1,213,748 | $22,563,575 | $21,422,652 | -$1,140,923 | -5.06% | |
| Principal Financial Group Inc | 0.01% | 1,196,049 | $22,234,551 | $21,110,265 | -$1,124,286 | -5.06% | |
| Voya Investment Management Llc | 0.02% | 1,168,228 | $21,717,359 | $20,619,224 | -$1,098,135 | -5.06% | |
| Congress Asset Management Co | 0.15% | 1,114,061 | $20,710,394 | $19,663,177 | -$1,047,217 | -5.06% | |
| Bnp Paribas Financial Markets | 0.01% | 1,111,397 | $20,660,870 | $19,616,157 | -$1,044,713 | -5.06% | |
| Allspring Global Investments Holdings, Llc | 0.03% | 1,059,030 | $19,761,500 | $18,691,880 | -$1,069,621 | -5.41% | |
| Schroder Investment Management Group | 0.02% | 1,136,000 | $19,675,520 | $20,050,400 | +$374,880 | +1.91% |
Frequently asked questions about MIR
Who owns the most MIR stock?
The largest holders of MIR are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for MIRION TECHNOLOGIES INC (MIR).
Is MIR widely held by superinvestors?
Many widely followed stocks like MIR appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly MIR is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.