Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
390 institutional managers reported holding MGY for the quarter ended Mar 31, 2026. Reported positions total over 95% of shares outstanding; the top 10 hold 58%. 66 opened new positions; 49 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 29.49M | 16.09% | $931.0M | added +6.6% | 2018 Q3 |
| Vanguard Group | 21.63M | 11.80% | $682.8M | added +10% | 2018 Q3 |
| American Century Companies INC | 10.51M | 5.73% | $331.8M | trimmed -4.7% | 2019 Q3 |
| State Street | 9.50M | 5.18% | $299.8M | added +7.9% | 2018 Q3 |
| Dimensional Fund Advisors | 7.03M | 3.83% | $221.9M | added +5.9% | 2021 Q1 |
| Janus Henderson | 6.28M | 3.43% | $198.2M | added +2.8% | 2021 Q3 |
| Arrowstreet Capital | 6.26M | 3.42% | $197.7M | added +790.8% | 2025 Q1 |
| T. Rowe Price Investment Management, INC. | 5.19M | 2.83% | $164.0M | added +236% | 2022 Q3 |
| Nomura Asset Management International INC. | 4.97M | 2.71% | $157.0M | unchanged | 2024 Q3 |
| TD Asset Management INC | 4.94M | 2.70% | $156.0M | trimmed -12.9% | 2018 Q3 |
| Geode Capital | 4.54M | 2.48% | $143.3M | added +2.3% | 2018 Q2 |
| AllianceBernstein | 4.45M | 2.43% | $140.5M | trimmed -6.2% | 2018 Q3 |
| Epoch Investment Partners, INC. | 4.28M | 2.33% | $135.0M | trimmed -19.8% | 2024 Q3 |
| Bank OF America CORP /DE/ | 3.88M | 2.12% | $122.4M | added +20.5% | 2018 Q4 |
| Boston Trust Walden CORP | 3.23M | 1.76% | $101.9M | trimmed -22.6% | 2024 Q1 |
| Goldman Sachs | 3.13M | 1.71% | $98.9M | added +40.7% | 2018 Q3 |
| Victory Capital Management INC | 3.09M | 1.69% | $97.6M | trimmed -13.9% | 2018 Q3 |
| Gw&k Investment Management, LLC | 3.08M | 1.68% | $97.3M | trimmed -2.8% | 2021 Q1 |
| Morgan Stanley | 3.03M | 1.65% | $95.6M | added +8.3% | 2018 Q3 |
| Systematic Financial Management LP | 2.81M | 1.53% | $88.8M | trimmed -4.3% | 2018 Q3 |
| Allspring Global Investments Holdings, LLC | 2.70M | 1.47% | $85.2M | trimmed -7.9% | 2021 Q4 |
| Silvercrest Asset Management Group LLC | 2.67M | 1.46% | $84.2M | trimmed -20% | 2018 Q4 |
| Charles Schwab Investment Management | 2.61M | 1.43% | $82.5M | added +4.8% | 2018 Q3 |
| Nuveen | 2.25M | 1.23% | $71.1M | added +23.8% | 2019 Q2 |
| Loomis Sayles & CO L P | 2.18M | 1.19% | $68.8M | trimmed -6% | 2022 Q2 |
| Stephens Investment Management Group LLC | 2.17M | 1.19% | $68.6M | added +0.8% | 2021 Q3 |
| Northern Trust | 2.13M | 1.16% | $67.3M | added +2.9% | 2018 Q3 |
| BNY Mellon | 1.94M | 1.06% | $61.4M | trimmed -1.1% | 2018 Q3 |
| Renaissance Technologies | 1.70M | 0.93% | $53.7M | added +43.7% | 2022 Q1 |
| Two Sigma | 1.69M | 0.92% | $53.5M | added +297.6% | 2019 Q3 |
| Westwood Holdings Group INC | 1.59M | 0.87% | $50.2M | trimmed -9.7% | 2025 Q4 |
| Principal Financial Group INC | 1.54M | 0.84% | $48.8M | trimmed -2.4% | 2019 Q3 |
| Manufacturers Life Insurance Company, THE | 1.53M | 0.84% | $48.4M | trimmed -22.9% | 2018 Q3 |
| UBS | 1.38M | 0.75% | $43.5M | added +28% | 2018 Q3 |
| Bessemer Group INC | 1.25M | 0.68% | $39.6M | added +12.3% | 2021 Q3 |
| Fred Alger Management, LLC | 1.20M | 0.65% | $37.7M | added +594.1% | 2018 Q3 |
| Voloridge Investment Management | 983.9k | 0.54% | $31.1M | added +1.5% | 2024 Q2 |
| First Trust Advisors LP | 976.4k | 0.53% | $30.8M | added +11.6% | 2020 Q1 |
| SIR Capital Management, L.p. | 851.1k | 0.46% | $26.9M | trimmed -15.8% | 2024 Q2 |
| Public Sector Pension Investment Board | 801.8k | 0.44% | $25.3M | added +5.7% | 2024 Q1 |
| Aberdeen Group plc | 768.1k | 0.42% | $24.2M | added +56.7% | 2023 Q3 |
| Invesco | 704.7k | 0.39% | $22.2M | trimmed -1.5% | 2019 Q2 |
| Point72 | 692.6k | 0.38% | $21.9M | added +129.2% | 2025 Q4 |
| Heartland Advisors INC | 630.5k | 0.34% | $19.9M | trimmed -3.2% | 2024 Q1 |
| Millennium Management | 599.0k | 0.33% | $18.9M | added +61.2% | 2024 Q2 |
| Rhumbline Advisers | 577.3k | 0.32% | $18.2M | added +1% | 2019 Q2 |
| Algert Global LLC | 523.6k | 0.29% | $16.5M | opened | 2026 Q1 |
| AQR Capital | 497.9k | 0.27% | $15.7M | added +56.3% | 2021 Q2 |
| Gilder Gagnon Howe & CO LLC | 486.5k | 0.27% | $15.4M | trimmed -25.6% | 2018 Q4 |
| SEI Investments CO | 455.4k | 0.25% | $14.4M | added +93.2% | 2019 Q1 |
Largest 50 of 390 shown; the full ranked, searchable register is at boothcheck.com/holders/MGY. 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.