Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
268 institutional managers reported holding MTX for the quarter ended Mar 31, 2026. Reported positions total over 95% of shares outstanding; the top 10 hold 67%. 37 opened new positions; 35 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 4.81M | 15.52% | $341.4M | added +0.8% | ≤2013 |
| FMR (Fidelity) | 4.26M | 13.76% | $302.6M | added +56.6% | 2017 Q2 |
| Vanguard Group | 3.53M | 11.38% | $250.3M | unchanged | ≤2013 |
| Dimensional Fund Advisors | 1.97M | 6.37% | $140.1M | unchanged | ≤2013 |
| Nomura Asset Management International INC. | 1.45M | 4.69% | $103.2M | trimmed -7% | 2025 Q4 |
| State Street | 1.21M | 3.90% | $85.8M | trimmed -1% | ≤2013 |
| American Century Companies INC | 1.02M | 3.29% | $72.3M | trimmed -22.7% | ≤2013 |
| Geode Capital | 957.5k | 3.09% | $67.9M | added +6.6% | ≤2013 |
| Brandes Investment Partners, LP | 841.0k | 2.71% | $59.7M | added +2.6% | 2024 Q4 |
| Mirae Asset Global Etfs Holdings LTD. | 560.9k | 1.81% | $39.8M | added +40.7% | 2018 Q3 |
| Charles Schwab Investment Management | 547.3k | 1.77% | $38.8M | trimmed -8.4% | ≤2013 |
| Snyder Capital Management L P | 501.4k | 1.62% | $35.6M | trimmed -7.1% | 2016 Q2 |
| Ameriprise Financial INC | 469.5k | 1.51% | $33.3M | added +3.4% | ≤2013 |
| Nuveen | 405.6k | 1.31% | $28.8M | added +1.2% | ≤2013 |
| D. E. Shaw | 367.3k | 1.19% | $26.1M | trimmed -9.2% | ≤2013 |
| Goldman Sachs | 350.5k | 1.13% | $24.9M | added +12.8% | ≤2013 |
| Allspring Global Investments Holdings, LLC | 348.3k | 1.12% | $24.7M | trimmed -15% | 2021 Q4 |
| Northern Trust | 341.3k | 1.10% | $24.2M | added +5.7% | ≤2013 |
| Bank OF America CORP /DE/ | 335.5k | 1.08% | $23.8M | unchanged | ≤2013 |
| Gw&k Investment Management, LLC | 321.7k | 1.04% | $22.8M | trimmed -1.8% | 2020 Q1 |
| Morgan Stanley | 274.3k | 0.89% | $19.5M | trimmed -2.8% | ≤2013 |
| BNY Mellon | 270.7k | 0.87% | $19.2M | trimmed -2.4% | ≤2013 |
| LSV Asset Management | 268.0k | 0.86% | $19.0M | added +26.7% | 2024 Q2 |
| Gamco Investors, INC. et al | 254.5k | 0.82% | $18.1M | trimmed -7.8% | ≤2013 |
| AQR Capital | 217.2k | 0.70% | $15.4M | added +32.6% | ≤2013 |
| CSM Advisors, LLC | 205.6k | 0.66% | $14.6M | added +8.4% | 2025 Q2 |
| UBS | 198.2k | 0.64% | $14.1M | added +63.9% | ≤2013 |
| Panagora Asset Management INC | 197.6k | 0.64% | $14.0M | unchanged | ≤2013 |
| SG Capital Management LLC | 187.2k | 0.60% | $13.3M | added +26.1% | 2025 Q2 |
| Principal Financial Group INC | 179.4k | 0.58% | $12.7M | trimmed -1.9% | ≤2013 |
| Qube Research & Technologies LTD | 164.4k | 0.53% | $11.7M | added +10.5% | 2021 Q2 |
| Glenmede Trust CO NA | 160.8k | 0.52% | $11.4M | trimmed -8.9% | 2025 Q2 |
| Royce & Associates | 160.3k | 0.52% | $11.4M | added +0.6% | ≤2013 |
| Invesco | 140.6k | 0.45% | $10.0M | added +4.2% | ≤2013 |
| Arrowstreet Capital | 125.6k | 0.41% | $8.9M | added +212% | 2024 Q2 |
| Public Sector Pension Investment Board | 111.4k | 0.36% | $7.9M | added +3.4% | 2022 Q3 |
| Universal- Beteiligungs- und Servicegesellschaft mbH | 108.5k | 0.35% | $7.7M | added +62.8% | 2025 Q1 |
| First Manhattan CO. LLC. | 101.3k | 0.33% | $7.2M | trimmed -16% | ≤2013 |
| GAMCO (Gabelli) | 97.2k | 0.31% | $6.9M | added +4.4% | ≤2013 |
| Rhumbline Advisers | 91.3k | 0.29% | $6.5M | added +2% | ≤2013 |
| HRT Financial LP | 89.0k | 0.29% | $6.3M | trimmed -24.6% | 2023 Q1 |
| Kennedy Capital Management LLC | 84.1k | 0.27% | $6.0M | added +2.2% | 2025 Q3 |
| Franklin Resources | 83.9k | 0.27% | $6.0M | added +76% | 2014 Q1 |
| Legal & General Group PLC | 71.7k | 0.23% | $5.1M | trimmed -9.2% | 2014 Q3 |
| Skylands Capital, LLC | 65.3k | 0.21% | $4.6M | trimmed -15.2% | 2022 Q3 |
| Dean Investment Associates, LLC | 65.2k | 0.21% | $4.6M | added +71.4% | 2024 Q4 |
| Two Sigma | 62.3k | 0.20% | $4.4M | trimmed -15.9% | 2022 Q3 |
| Swiss National Bank | 61.5k | 0.20% | $4.4M | unchanged | ≤2013 |
| Jane Street | 58.9k | 0.19% | $4.2M | added +29.1% | 2020 Q2 |
| Martingale Asset Management L P | 52.8k | 0.17% | $3.7M | added +10.7% | 2024 Q1 |
Largest 50 of 268 shown; the full ranked, searchable register is at boothcheck.com/holders/MTX. 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.