Who owns Magnolia Oil & Gas Corporation (MGY)
Which tracked institutional funds hold MGY, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See MGY company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
The tracked-fund tape on MGY is one-sided between 2025-Q4 and 2026-Q1: 192 added or opened and 43 trimmed or exited — on balance accumulating.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
MGY’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes MGY more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in MGY divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 401 tracked filers holding MGY, 221 increased or opened the position and 188 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in MGY between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 26
- VANGUARD PORTFOLIO MANAGEMENT LLC$410M
- VANGUARD CAPITAL MANAGEMENT LLC$227M
- VANGUARD FIDUCIARY TRUST CO$37M
- ALGERT GLOBAL LLC$17M
- Clark Capital Management Group, Inc.$7M
- Emerald Investment Advisers, LLC$6M
Full exits 24
- VANGUARD GROUP INC$424M
- WELLINGTON MANAGEMENT GROUP LLP$114M
- HITE Hedge Asset Management LLC$32M
- Brandywine Global Investment Management, LLC$16M
- Jefferies Financial Group Inc.$13M
- Pacer Advisors, Inc.$13M
Largest adds
- BlackRock, Inc.$210M
- ARROWSTREET CAPITAL, LIMITED PARTNERSHIP$182M
- T. Rowe Price Investment Management, Inc.$130M
- STATE STREET CORP$107M
- AMERICAN CENTURY COMPANIES INC$90M
- DIMENSIONAL FUND ADVISORS LP$77M
Largest trims
- BALYASNY ASSET MANAGEMENT L.P.$16M
- ALLIANCEBERNSTEIN L.P.$6M
- D. E. Shaw & Co., Inc.$5M
- Illinois Municipal Retirement Fund$3M
- Connor, Clark & Lunn Investment Management Ltd.$2M
- Man Group plc$2M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. trimmed | 25,843,552 | $816M | 12.0% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 12,983,395 | $410M | 6.0% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 10,509,240 | $332M | 4.9% | 2026-Q1 |
| STATE STREET CORP added | 9,496,275 | $300M | 4.4% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 7,188,424 | $227M | 3.3% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 7,028,781 | $222M | 3.3% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 6,279,636 | $198M | 2.9% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 6,263,808 | $198M | 2.9% | 2026-Q1 |
| T. Rowe Price Investment Management, Inc. added | 5,193,887 | $164M | 2.4% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. added | 4,972,261 | $157M | 2.3% | 2026-Q1 |
| TD Asset Management Inc trimmed | 4,941,979 | $156M | 2.3% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 4,538,112 | $143M | 2.1% | 2026-Q1 |
| Epoch Investment Partners, Inc. trimmed | 4,275,509 | $135M | 2.0% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 3,877,361 | $122M | 1.8% | 2026-Q1 |
| Boston Trust Walden Corp trimmed | 3,227,906 | $102M | 1.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 3,131,348 | $99M | 1.4% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 3,091,053 | $98M | 1.4% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. trimmed | 4,451,242 | $97M | 1.4% | 2026-Q1 |
| GW&K Investment Management, LLC trimmed | 3,081,264 | $97M | 1.4% | 2026-Q1 |
| MORGAN STANLEY added | 3,027,975 | $96M | 1.4% | 2026-Q1 |
| SYSTEMATIC FINANCIAL MANAGEMENT LP trimmed | 2,813,278 | $89M | 1.3% | 2026-Q1 |
| SILVERCREST ASSET MANAGEMENT GROUP LLC trimmed | 2,666,648 | $84M | 1.2% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 2,613,478 | $83M | 1.2% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC trimmed | 2,699,004 | $81M | 1.2% | 2026-Q1 |
| Nuveen, LLC added | 2,253,068 | $71M | 1.0% | 2026-Q1 |
| LOOMIS SAYLES & CO L P trimmed | 2,179,644 | $69M | 1.0% | 2026-Q1 |
| Stephens Investment Management Group LLC added | 2,172,120 | $69M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 2,132,100 | $67M | 1.0% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 1,943,586 | $61M | 0.9% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 1,701,802 | $54M | 0.8% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 1,693,795 | $53M | 0.8% | 2026-Q1 |
| WESTWOOD HOLDINGS GROUP INC trimmed | 1,590,570 | $50M | 0.7% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC trimmed | 1,544,274 | $49M | 0.7% | 2026-Q1 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE trimmed | 1,534,372 | $48M | 0.7% | 2026-Q1 |
| BESSEMER GROUP INC added | 1,254,441 | $40M | 0.6% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 1,200,481 | $39M | 0.6% | 2026-Q1 |
| FRED ALGER MANAGEMENT, LLC added | 1,195,380 | $38M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 1,181,924 | $37M | 0.5% | 2026-Q1 |
| UBS Group AG added | 1,170,209 | $37M | 0.5% | 2026-Q1 |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC added | 983,876 | $31M | 0.5% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 976,356 | $31M | 0.5% | 2026-Q1 |
| SIR Capital Management, L.P. trimmed | 851,094 | $27M | 0.4% | 2026-Q1 |
| Public Sector Pension Investment Board added | 801,757 | $25M | 0.4% | 2026-Q1 |
| Aberdeen Group plc added | 768,072 | $24M | 0.4% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 692,589 | $22M | 0.3% | 2026-Q1 |
| HEARTLAND ADVISORS INC trimmed | 630,475 | $20M | 0.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 599,017 | $19M | 0.3% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 577,269 | $18M | 0.3% | 2026-Q1 |
| Invesco Ltd. trimmed | 538,494 | $17M | 0.2% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 523,620 | $17M | 0.2% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 490,722 | $15M | 0.2% | 2026-Q1 |
| GILDER GAGNON HOWE & CO LLC trimmed | 486,526 | $15M | 0.2% | 2026-Q1 |
| SEI INVESTMENTS CO added | 455,352 | $14M | 0.2% | 2026-Q1 |
| Squarepoint Ops LLC added | 454,853 | $14M | 0.2% | 2026-Q1 |
| OBERWEIS ASSET MANAGEMENT INC/ added | 454,466 | $14M | 0.2% | 2026-Q1 |
| Creative Planning added | 430,579 | $14M | 0.2% | 2026-Q1 |
| ENVESTNET ASSET MANAGEMENT INC added | 422,086 | $13M | 0.2% | 2026-Q1 |
| NEUBERGER BERMAN GROUP LLC added | 418,247 | $13M | 0.2% | 2026-Q1 |
| California Public Employees Retirement System added | 413,997 | $13M | 0.2% | 2026-Q1 |
| Corigliano Investment Advisers, LLC trimmed | 398,000 | $13M | 0.2% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD trimmed | 386,531 | $12M | 0.2% | 2026-Q1 |
| Legal & General Group Plc trimmed | 385,963 | $12M | 0.2% | 2026-Q1 |
| Foster Victor Wealth Advisors, LLC added | 424,272 | $12M | 0.2% | 2026-Q1 |
| BARROW HANLEY MEWHINNEY & STRAUSS LLC added | 381,899 | $12M | 0.2% | 2026-Q1 |
| NORDEA INVESTMENT MANAGEMENT AB trimmed | 362,828 | $12M | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 364,172 | $11M | 0.2% | 2026-Q1 |
| Edgestream Partners, L.P. added | 352,998 | $11M | 0.2% | 2026-Q1 |
| Swiss National Bank added | 348,300 | $11M | 0.2% | 2026-Q1 |
| DIAMOND HILL CAPITAL MANAGEMENT INC trimmed | 325,021 | $10M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 301,877 | $10M | 0.1% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 283,586 | $9M | 0.1% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 277,770 | $9M | 0.1% | 2026-Q1 |
| Universal- Beteiligungs- und Servicegesellschaft mbH trimmed | 275,307 | $9M | 0.1% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 273,438 | $9M | 0.1% | 2026-Q1 |
| Trexquant Investment LP trimmed | 258,646 | $8M | 0.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 251,446 | $8M | 0.1% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. trimmed | 249,319 | $8M | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 244,319 | $8M | 0.1% | 2026-Q1 |
| Rafferty Asset Management, LLC added | 239,979 | $8M | 0.1% | 2026-Q1 |
| Campbell & CO Investment Adviser LLC added | 237,440 | $7M | 0.1% | 2026-Q1 |
| PRUDENTIAL FINANCIAL INC added | 234,640 | $7M | 0.1% | 2026-Q1 |
| KING LUTHER CAPITAL MANAGEMENT CORP trimmed | 232,258 | $7M | 0.1% | 2026-Q1 |
| FRANKLIN RESOURCES INC added | 225,326 | $7M | 0.1% | 2026-Q1 |
| DEUTSCHE BANK AG\ trimmed | 220,201 | $7M | 0.1% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 219,103 | $7M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 19,386,295 | $424M | 6.2% | 2025-Q4 stale |
| MACQUARIE GROUP LTD trimmed | 5,381,675 | $128M | 1.9% | 2025-Q3 stale |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 5,206,612 | $114M | 1.7% | 2025-Q4 stale |
| Encompass Capital Advisors LLC added | 2,182,088 | $52M | 0.8% | 2025-Q3 stale |
| EnerVest, Ltd. | 2,099,403 | $50M | 0.7% | 2025-Q3 stale |
| HITE Hedge Asset Management LLC added | 1,454,388 | $32M | 0.5% | 2025-Q4 stale |
| VALLEY WEALTH MANAGERS, INC. trimmed | 715,217 | $16M | 0.2% | 2025-Q2 stale |
| Brandywine Global Investment Management, LLC trimmed | 731,423 | $16M | 0.2% | 2025-Q4 stale |
| TimesSquare Capital Management, LLC added | 691,959 | $16M | 0.2% | 2025-Q2 stale |
| Jefferies Financial Group Inc. added | 614,682 | $13M | 0.2% | 2025-Q4 stale |
| Pacer Advisors, Inc. trimmed | 589,486 | $13M | 0.2% | 2025-Q4 stale |
| Ranger Investment Management, L.P. trimmed | 560,990 | $13M | 0.2% | 2025-Q2 stale |
| CAMBIAR INVESTORS LLC trimmed | 489,866 | $12M | 0.2% | 2025-Q1 stale |
| Aventail Capital Group, LP added | 400,928 | $10M | 0.1% | 2025-Q3 stale |
| OSTERWEIS CAPITAL MANAGEMENT INC trimmed | 325,647 | $7M | 0.1% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.