AMTM Institutional Ownership & Shareholders
AMENTUM HOLDINGS INC (AMTM) is currently held by 449 institutional investors tracked by InsiderSet, with a combined reported market value of approximately $4.27B based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
American Securities Llc is currently the largest disclosed institutional shareholder of AMTM tracked by InsiderSet, reporting ownership valued at approximately $930.70M in its June 30, 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 $1.01B, representing an estimated gain of +8.71% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 65% of the total disclosed AMTM value among the investors covered in this analysis. Major shareholders include American Securities Llc, Invesco Ltd., Blackrock, Inc., and several other long-term asset managers with concentrated positions in AMENTUM HOLDINGS INC (AMTM).
This page ranks the largest institutional AMTM 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
449
Total Reported Value
$4.27B
Largest Holder
American Securities Llc
Largest Position
$930.70M
Insider Transactions (90d)
1
Latest Filing Quarter
Q2 2026
New Institutional Positions
47
Funds Exiting Positions
1
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| American Securities Llc | 24.79% | 45,026,743 | $930,702,778 | $1,011,750,915 | +$81,048,137 | +8.71% | |
| Invesco Ltd. | 0.04% | 24,954,251 | $515,804,369 | $560,722,020 | +$44,917,651 | +8.71% | |
| Blackrock, Inc. | 0.01% | 17,906,984 | $370,137,359 | $402,369,930 | +$32,232,571 | +8.71% | |
| Primecap Management Co/Ca/ | 0.15% | 12,285,504 | $253,941,367 | $276,055,275 | +$22,113,908 | +8.71% | |
| Vanguard Portfolio Management Llc | 0.01% | 7,948,385 | $164,293,118 | $178,600,211 | +$14,307,093 | +8.71% | |
| Vanguard Capital Management Llc | 0.00% | 6,711,987 | $138,736,771 | $150,818,348 | +$12,081,577 | +8.71% | |
| Fmr Llc | 0.01% | 5,679,175 | $117,388,551 | $127,611,062 | +$10,222,511 | +8.71% | |
| Dimensional Fund Advisors Lp | 0.02% | 5,537,696 | $114,458,757 | $124,432,029 | +$9,973,272 | +8.71% | |
| State Street Corp | 0.00% | 5,151,772 | $106,487,127 | $115,760,317 | +$9,273,190 | +8.71% | |
| Frontier Capital Management Co Llc | 0.80% | 4,143,971 | $85,655,891 | $93,115,028 | +$7,459,137 | +8.71% | |
| Troluce Capital Advisors Llc | 27.60% | 3,565,399 | $73,696,797 | $80,114,516 | +$6,417,719 | +8.71% | |
| Geode Capital Management, Llc | 0.00% | 2,716,560 | $56,171,464 | $61,041,103 | +$4,869,639 | +8.67% | |
| Goldman Sachs Group Inc | 0.01% | 2,711,866 | $56,054,274 | $60,935,629 | +$4,881,355 | +8.71% | |
| Morgan Stanley | 0.00% | 2,662,329 | $55,030,365 | $59,822,533 | +$4,792,168 | +8.71% | |
| Mirae Asset Global Etfs Holdings Ltd. | 0.06% | 2,318,581 | $47,925,069 | $52,098,515 | +$4,173,446 | +8.71% | |
| Thompson Siegel & Walmsley Llc | 0.85% | 2,281,945 | $47,168,000 | $51,275,304 | +$4,107,304 | +8.71% | |
| Millennium Management Llc | 0.03% | 2,127,779 | $43,981,192 | $47,811,194 | +$3,830,002 | +8.71% | |
| Charles Schwab Investment Management Inc | 0.01% | 2,120,102 | $43,822,508 | $47,638,692 | +$3,816,184 | +8.71% | |
| Thrivent Financial For Lutherans | 0.07% | 2,105,802 | $43,527,000 | $47,317,371 | +$3,790,371 | +8.71% | |
| Bank Of America Corp | 0.00% | 2,042,897 | $42,226,681 | $45,903,896 | +$3,677,215 | +8.71% | |
| Verition Fund Management Llc | 0.29% | 2,019,334 | $41,739,634 | $45,374,435 | +$3,634,801 | +8.71% | |
| Van Eck Associates Corp | 0.03% | 1,988,898 | $41,110,521 | $44,690,538 | +$3,580,017 | +8.71% | |
| Voya Investment Management Llc | 0.04% | 1,974,191 | $40,806,528 | $44,360,072 | +$3,553,544 | +8.71% | |
| Ubs Group Ag | 0.01% | 1,545,183 | $31,938,933 | $34,720,262 | +$2,781,329 | +8.71% | |
| Norges Bank | 0.00% | 1,516,193 | $31,339,709 | $34,068,857 | +$2,729,148 | +8.71% | |
| Permian Investment Partners, Lp | 3.36% | 1,433,028 | $29,620,689 | $32,200,139 | +$2,579,450 | +8.71% | |
| 683 Capital Management, Llc | 2.09% | 1,100,000 | $22,737,000 | $24,717,000 | +$1,980,000 | +8.71% | |
| Loomis Sayles & Co L P | 0.03% | 1,042,522 | $21,548,933 | $23,425,469 | +$1,876,536 | +8.71% | |
| Qube Research & Technologies Ltd | 0.02% | 1,034,395 | $21,380,945 | $23,242,856 | +$1,861,911 | +8.71% | |
| Northern Trust Corp | 0.00% | 1,029,892 | $21,287,867 | $23,141,673 | +$1,853,806 | +8.71% | |
| Vanguard Fiduciary Trust Co | 0.00% | 968,451 | $20,017,882 | $21,761,094 | +$1,743,212 | +8.71% | |
| Bank Of New York Mellon Corp | 0.00% | 878,084 | $18,150,003 | $19,730,547 | +$1,580,544 | +8.71% | |
| Russell Investments Group, Ltd. | 0.02% | 840,642 | $17,375,794 | $18,889,226 | +$1,513,432 | +8.71% | |
| Avenir Corp | 2.04% | 811,726 | $16,778,376 | $18,239,483 | +$1,461,107 | +8.71% | |
| Cacti Asset Management Llc | 0.84% | 875,097 | $15,883,011 | $19,663,430 | +$3,780,419 | +23.80% | |
| Wells Fargo & Company/Mn | 0.00% | 750,214 | $15,506,913 | $16,857,309 | +$1,350,396 | +8.71% | |
| Ancora Advisors Llc | 0.29% | 715,652 | $14,792,526 | $16,080,700 | +$1,288,174 | +8.71% | |
| Royce & Associates Lp | 0.12% | 697,368 | $14,414,597 | $15,669,859 | +$1,255,262 | +8.71% | |
| Segra Capital Management, Llc | 2.83% | 774,867 | $14,040,590 | $17,411,261 | +$3,370,671 | +24.01% | |
| Hrt Financial Lp | 0.03% | 671,847 | $13,887,000 | $15,096,402 | +$1,209,402 | +8.71% | |
| Citadel Advisors Llc | 0.01% | 670,684 | $13,863,038 | $15,070,269 | +$1,207,231 | +8.71% | |
| Point72 Asset Management, L.P. | 0.02% | 649,984 | $13,435,169 | $14,605,140 | +$1,169,971 | +8.71% | |
| Principal Financial Group Inc | 0.01% | 730,842 | $13,242,857 | $16,422,020 | +$3,179,163 | +24.01% | |
| Aqr Capital Management Llc | 0.00% | 601,900 | $12,423,224 | $13,524,693 | +$1,101,469 | +8.87% | |
| First Trust Advisors Lp | 0.01% | 547,907 | $11,325,031 | $12,311,470 | +$986,439 | +8.71% | |
| Sequoia Fund | Ruane, Cunniff & Goldfarb | 0.17% | 537,213 | $11,104,193 | $12,071,176 | +$966,983 | +8.71% |
| Public Sector Pension Investment Board | 0.03% | 528,821 | $10,930,730 | $11,882,608 | +$951,878 | +8.71% | |
| Loews Corp | 0.08% | 500,000 | $10,335,000 | $11,235,000 | +$900,000 | +8.71% | |
| Shapiro Capital Management Llc | 0.60% | 475,970 | $9,838,300 | $10,695,046 | +$856,746 | +8.71% | |
| First National Bank Of Omaha | 0.27% | 475,992 | $9,721,259 | $10,695,540 | +$974,281 | +10.02% |
Frequently asked questions about AMTM
Who are the largest institutional holders of AMTM?
The largest institutional holders of AMTM reported in the latest SEC Form 13F filings include American Securities Llc, Invesco Ltd., Blackrock, Inc., Primecap Management Co/Ca/, and Vanguard Portfolio Management Llc. InsiderSet ranks institutional holders by their latest reported AMTM position.
What is AMTM institutional ownership?
This page tracks AMTM positions reported by institutional investment managers through SEC Form 13F. AMENTUM HOLDINGS INC (AMTM) institutional ownership on InsiderSet reflects disclosed 13F holdings among the managers we analyze, not every shareholder of the stock.
How many institutions own AMTM?
InsiderSet currently tracks 449 institutional managers reporting AMTM holdings in the latest available 13F data. This count reflects institutions included in the SEC Form 13F filings analyzed by InsiderSet and should not be interpreted as the total number of AMTM shareholders.
How much AMTM stock do institutions own?
Institutional investment managers disclosed approximately $4.27B in AMTM holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value.
When was AMTM institutional ownership last updated?
The latest AMTM institutional ownership data on InsiderSet is based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time institutional holdings.
Are institutional AMTM holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by institutional investment managers as of the end of the reporting quarter. An institution may have changed its AMTM position after the reporting date.
Are institutions buying or selling AMTM?
Institutional buying and selling can be analyzed by comparing AMTM positions across consecutive 13F reporting periods. InsiderSet's AMTM Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View AMTM ownership changes.
How has AMTM institutional ownership changed over time?
InsiderSet tracks AMTM institutional holdings across multiple 13F reporting periods, allowing investors to compare institutional holder counts, reported value, and reported shares over time.