Mirion Technologies, Inc. (MIR) Ownership
MIR ownership summary
as of October 18, 2026- Institutions
- 114.1% of shares outstanding
- Insiders
- 3.42% of shares outstanding
- Shares outstanding
- 243.3M
- Float
- 227.1M shares available to trade
- Short interest
- 22.76% 38.4M shares short
- Days to cover
- 9.86 short interest up 6.9% vs prior month
- Institutions 114.14%
- Insiders 3.42%
MIR top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 15.73% | 38.3M | $579.7M | +404,610 (+1.1%) | June 30, 2026 |
| 2 | Vanguard Portfolio Management, LLC | 7.47% | 18.2M | $275.4M | +274,128 (+1.5%) | June 30, 2026 |
| 3 | T. Rowe Price Investment Management,Inc. | 5.87% | 14.3M | $216.5M | −339,720 (−2.3%) | June 30, 2026 |
| 4 | Vanguard Capital Management, LLC | 4.36% | 10.6M | $160.8M | +108,674 (+1.0%) | June 30, 2026 |
| 5 | The Goldman Sachs Group Inc | 4.28% | 10.4M | $157.7M | +3.1M (+41.6%) | June 30, 2026 |
| 6 | State Street Corp | 4.08% | 9.9M | $150.3M | +493,592 (+5.2%) | June 30, 2026 |
| 7 | Alyeska Investment Group, L.P. | 3.92% | 9.5M | $144.5M | +6.8M (+252.9%) | June 30, 2026 |
| 8 | Cooperman Leon G | 3.45% | 8.4M | $127.0M | — | June 30, 2026 |
| 9 | FMR Inc | 3.01% | 7.3M | $111.0M | +777,694 (+11.9%) | June 30, 2026 |
| 10 | Congress Asset Management Company, LLP | 2.75% | 6.7M | $101.3M | +5.6M (+500.1%) | June 30, 2026 |
| 11 | Geode Capital Management, LLC | 2.58% | 6.3M | $95.1M | +339,873 (+5.7%) | June 30, 2026 |
| 12 | Maverick Capital Ltd | 2.16% | 5.2M | $79.5M | +2.6M (+97.9%) | June 30, 2026 |
| 13 | Dimensional Fund Advisors, Inc. | 2.00% | 4.9M | $73.6M | +165,467 (+3.5%) | June 30, 2026 |
| 14 | Jupiter Topco LLC | 1.69% | 4.1M | $62.3M | +4.1M (0.0%) | June 30, 2026 |
| 15 | HHG PLC | 1.66% | 4.0M | $61.3M | −553,860 (−12.0%) | March 31, 2026 |
| 16 | BAMCO Inc | 1.61% | 3.9M | $59.2M | +2.7M (+221.8%) | June 30, 2026 |
| 17 | Morgan Stanley - Brokerage Accounts | 1.60% | 3.9M | $59.0M | +1.6M (+70.5%) | June 30, 2026 |
| 18 | Neuberger Berman Group LLC | 1.32% | 3.2M | $48.5M | +2.3M (+273.6%) | June 30, 2026 |
| 19 | American Century Companies Inc | 1.31% | 3.2M | $48.1M | +443,479 (+16.2%) | June 30, 2026 |
| 20 | Amvescap Plc. | 1.14% | 2.8M | $42.0M | +475,339 (+20.7%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 17 holders added 32.3M shares and 2 cut 894K.
MIR top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Small-Cap ETF | 5.82% | 14.5M | $219.5M | +3,264 (+0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 2.97% | 7.4M | $112.0M | −10,088 (−0.1%) | August 31, 2026 |
| 3 | T. Rowe Price Small-Cap Stock | 2.75% | 6.8M | $103.8M | +1.2M (+20.8%) | August 31, 2026 |
| 4 | iShares Russell 2000 ETF | 2.52% | 6.3M | $95.0M | −72,256 (−1.1%) | September 30, 2026 |
| 5 | Vanguard Small Cap Index | 2.15% | 5.3M | $81.0M | +5,370 (+0.1%) | August 31, 2026 |
| 6 | Vanguard Information Technology ETF | 2.07% | 5.2M | $78.3M | −7,625 (−0.1%) | August 31, 2026 |
| 7 | T. Rowe Price Instl Small-Cap Stock | 1.51% | 3.7M | $56.8M | +672,445 (+21.9%) | August 31, 2026 |
| 8 | Vanguard MStar Small Cap Value Index | 1.36% | 3.4M | $51.5M | +2,665 (+0.1%) | August 31, 2026 |
| 9 | Janus Henderson Triton D | 1.12% | 2.8M | $42.4M | — | August 31, 2026 |
| 10 | Congress Small Cap Growth Institutional | 1.10% | 2.7M | $41.6M | +20,000 (+0.7%) | August 31, 2026 |
| 11 | Fidelity Small Cap Index | 1.06% | 2.6M | $40.1M | +21,718 (+0.8%) | July 31, 2026 |
| 12 | American Century Small Cap Growth Inv | 0.97% | 2.4M | $36.7M | +665,709 (+37.9%) | June 30, 2026 |
| 13 | GS Global Ftr Tech Ldr Eq I USD Acc | 0.92% | 2.3M | $34.7M | +39,280 (+1.7%) | July 31, 2026 |
| 14 | iShares S&P Small-Cap 600 Growth ETF | 0.90% | 2.3M | $34.1M | — | September 30, 2026 |
| 15 | State Street SPDR Port S&P 600 Sm CpETF | 0.89% | 2.2M | $33.6M | — | September 30, 2026 |
| 16 | Baron Small Cap Retail | 0.80% | 2.0M | $30.3M | +500,000 (+33.3%) | September 30, 2026 |
| 17 | iShares Russell 2000 Growth ETF | 0.79% | 2.0M | $29.8M | −2,486 (−0.1%) | September 30, 2026 |
| 18 | TCW Transform Systems ETF | 0.77% | 1.9M | $28.9M | +6,815 (+0.4%) | September 30, 2026 |
| 19 | Neuberger Genesis Inv | 0.76% | 1.9M | $28.7M | +1.9M (0.0%) | June 30, 2026 |
| 20 | Baron Discovery Institutional | 0.61% | 1.5M | $23.1M | +325,000 (+27.1%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
MIR insider transactions
latest 7| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-02-19 | Ro Khanna | Buy | $21.50 | — | — |
| 2025-12-10 | Lawrence D Kingsley | Sell | $24.73 | 350,000 | $8.7M |
| 2025-11-21 | Lawrence D Kingsley | Sell | $23.83 | 300,000 | $7.1M |
| 2025-09-24 | Ro Khanna | Buy | $21.93 | — | — |
| 2025-08-11 | Thomas D Logan | Sell | $21.31 | 325,000 | $6.9M |
| 2025-06-27 | Ro Khanna | Buy | $21.76 | — | — |
| 2025-05-21 | Lawrence D Kingsley | Sell | $17.94 | 500,000 | $9.0M |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
MIR shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns MIR
Institutional investors own 114.1% of Mirion Technologies's shares and insiders 3.42%. The largest holder is BlackRock Inc with 15.73% of the shares (38.3M), as of June 30, 2026. Among the top 20 institutions, 17 added shares and 2 reduced their stake in the latest filings. Short interest is 22.76% of the float, or 9.86 days of average trading volume. The share count rose 1,197.7% since 2018.
Related: MIR analyst forecast, MIR key metrics. See the MIR stock overview for the latest quote and news.
MIR ownership FAQ
Who owns the most Mirion Technologies stock?
The largest shareholders of Mirion Technologies are BlackRock Inc (15.73%), Vanguard Portfolio Management, LLC (7.47%), T. Rowe Price Investment Management,Inc. (5.87%), Vanguard Capital Management, LLC (4.36%), The Goldman Sachs Group Inc (4.28%).
What percentage of Mirion Technologies is owned by institutions?
Institutions hold 114.1% of Mirion Technologies's shares outstanding; insiders hold 3.42%.
Which funds own Mirion Technologies?
The largest fund holders of Mirion Technologies are iShares Core S&P Small-Cap ETF (5.82%), Vanguard MStar Total Stk Mkt Idx Invest (2.97%), T. Rowe Price Small-Cap Stock (2.75%), iShares Russell 2000 ETF (2.52%), Vanguard Small Cap Index (2.15%).
What is Mirion Technologies's short interest?
38.4M shares of Mirion Technologies were sold short, 22.76% of the float; at the average daily volume it would take 9.86 days to cover.
Are insiders buying or selling Mirion Technologies?
Of the latest 7 reported insider transactions in Mirion Technologies (since May 21, 2025), 3 were purchases and 4 were sales.
How many shares of Mirion Technologies are outstanding?
Mirion Technologies has 243.3M shares outstanding, of which 227.1M are in the public float.