Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
472 institutional managers reported holding AMTM for the quarter ended Mar 31, 2026. Together they hold about 86% of shares outstanding; the top 10 hold 57%. 63 opened new positions; 71 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| American Securities LLC (focused) | 45.03M | 18.38% | $1.17B | unchanged | 2025 Q1 |
| Invesco | 21.47M | 8.77% | $560.0M | trimmed -1.6% | 2024 Q3 |
| BlackRock | 17.84M | 7.28% | $465.3M | added +2.2% | 2024 Q3 |
| Vanguard Group | 15.70M | 6.41% | $409.4M | added +1.7% | 2024 Q3 |
| PRIMECAP Management | 12.09M | 4.93% | $315.2M | unchanged | 2024 Q3 |
| Legacy Advisors, LLC | 9.06M | 3.70% | $236.4M | trimmed -7.6% | 2025 Q4 |
| FMR (Fidelity) | 5.58M | 2.28% | $145.5M | trimmed -16.8% | 2024 Q3 |
| State Street | 5.08M | 2.07% | $132.5M | unchanged | 2024 Q3 |
| Frontier Capital Management CO LLC | 4.93M | 2.01% | $128.6M | trimmed -14.6% | 2025 Q1 |
| Dimensional Fund Advisors | 3.79M | 1.55% | $98.8M | added +106.6% | 2024 Q3 |
| Geode Capital | 2.81M | 1.15% | $73.4M | added +5.8% | 2024 Q3 |
| Mirae Asset Global Etfs Holdings LTD. | 2.79M | 1.14% | $72.6M | added +42% | 2024 Q3 |
| Focus Partners Wealth | 2.60M | 1.06% | $67.9M | trimmed -6.8% | 2024 Q3 |
| Bank OF America CORP /DE/ | 2.41M | 0.98% | $62.7M | added +107.8% | 2024 Q3 |
| Morgan Stanley | 2.23M | 0.91% | $58.3M | added +7.7% | 2024 Q3 |
| Thrivent Financial for Lutherans | 2.10M | 0.86% | $54.8M | added +1.5% | 2024 Q3 |
| Arvin Capital Management LP (focused) | 2.07M | 0.84% | $54.0M | added +26.6% | 2024 Q4 |
| Charles Schwab Investment Management | 2.07M | 0.84% | $53.9M | added +5.9% | 2024 Q3 |
| UBS | 1.96M | 0.80% | $51.1M | added +326.6% | 2024 Q3 |
| Point72 | 1.63M | 0.67% | $42.5M | added +134.5% | 2024 Q3 |
| Ruane Cunniff (Sequoia) (focused) | 1.62M | 0.66% | $42.3M | trimmed -32.2% | 2024 Q3 |
| Segra Capital Management, LLC (focused) | 1.61M | 0.66% | $42.1M | added +166.7% | 2025 Q3 |
| Permian Investment Partners, LP (focused) | 1.57M | 0.64% | $40.9M | opened | 2026 Q1 |
| Toronto Dominion Bank | 1.57M | 0.64% | $40.8M | opened | 2026 Q1 |
| Thompson Siegel & Walmsley LLC | 1.53M | 0.62% | $39.8M | trimmed -20.6% | 2024 Q3 |
| Brightline Capital Management, LLC (focused) | 1.40M | 0.57% | $36.4M | unchanged | 2025 Q2 |
| Verition Fund Management | 1.30M | 0.53% | $33.9M | added +50% | 2024 Q4 |
| Voya Investment Management LLC | 1.20M | 0.49% | $31.3M | added +4.5% | 2024 Q4 |
| Goldman Sachs | 1.13M | 0.46% | $29.5M | added +75.6% | 2024 Q3 |
| Loomis Sayles & CO L P | 1.08M | 0.44% | $28.2M | trimmed -3.4% | 2025 Q1 |
| Troluce Capital Advisors LLC (focused) | 1.00M | 0.41% | $26.1M | opened | 2026 Q1 |
| Northern Trust | 984.1k | 0.40% | $25.7M | added +3.3% | 2024 Q3 |
| Cooper Creek Partners Management LLC | 929.3k | 0.38% | $24.2M | trimmed -40.2% | 2025 Q4 |
| BNY Mellon | 908.6k | 0.37% | $23.7M | trimmed -1.5% | 2024 Q3 |
| Two Sigma | 900.2k | 0.37% | $23.5M | added +41.1% | 2024 Q3 |
| Cacti Asset Management LLC | 881.7k | 0.36% | $23.0M | unchanged | 2024 Q4 |
| Moore Capital | 873.6k | 0.36% | $22.8M | added +83.8% | 2024 Q4 |
| Nuveen | 871.8k | 0.36% | $22.7M | added +7.1% | 2024 Q3 |
| Avenir CORP | 841.1k | 0.34% | $21.9M | trimmed -1.2% | 2024 Q4 |
| 683 Capital Management, LLC | 775.0k | 0.32% | $20.2M | trimmed -7.2% | 2024 Q4 |
| Principal Financial Group INC | 744.7k | 0.30% | $19.4M | added +2.2% | 2024 Q3 |
| Russell Investments Group, LTD. | 713.8k | 0.29% | $18.6M | added +63.3% | 2024 Q3 |
| Ancora Advisors LLC | 703.1k | 0.29% | $18.3M | added +74.8% | 2024 Q3 |
| Penn Capital Management Company, LLC | 694.4k | 0.28% | $18.1M | trimmed -6.7% | 2024 Q4 |
| FIL LTD | 652.2k | 0.27% | $17.0M | trimmed -54.4% | 2024 Q3 |
| Wells Fargo & COMPANY/MN | 636.7k | 0.26% | $16.6M | added +37% | 2024 Q3 |
| Millennium Management | 631.1k | 0.26% | $16.5M | added +931.4% | 2024 Q3 |
| Public Sector Pension Investment Board | 549.8k | 0.22% | $14.3M | added +3.6% | 2024 Q4 |
| Royce & Associates | 549.8k | 0.22% | $14.3M | added +11% | 2024 Q3 |
| Susquehanna International Group | 547.8k | 0.22% | $14.3M | added +149.1% | 2024 Q3 |
Largest 50 of 472 shown; the full ranked, searchable register is at boothcheck.com/holders/AMTM. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.