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Institutional Ownership · SEC Form 13F

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.

401
Institutional holders
200M
Shares held (tracked funds)

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).

FundSharesReported value% of valueQuarter
BlackRock, Inc. trimmed25,843,552$816M12.0%2026-Q1
VANGUARD PORTFOLIO MANAGEMENT LLC new12,983,395$410M6.0%2026-Q1
AMERICAN CENTURY COMPANIES INC trimmed10,509,240$332M4.9%2026-Q1
STATE STREET CORP added9,496,275$300M4.4%2026-Q1
VANGUARD CAPITAL MANAGEMENT LLC new7,188,424$227M3.3%2026-Q1
DIMENSIONAL FUND ADVISORS LP added7,028,781$222M3.3%2026-Q1
JANUS HENDERSON GROUP PLC added6,279,636$198M2.9%2026-Q1
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added6,263,808$198M2.9%2026-Q1
T. Rowe Price Investment Management, Inc. added5,193,887$164M2.4%2026-Q1
NOMURA ASSET MANAGEMENT INTERNATIONAL INC. added4,972,261$157M2.3%2026-Q1
TD Asset Management Inc trimmed4,941,979$156M2.3%2026-Q1
GEODE CAPITAL MANAGEMENT, LLC added4,538,112$143M2.1%2026-Q1
Epoch Investment Partners, Inc. trimmed4,275,509$135M2.0%2026-Q1
BANK OF AMERICA CORP /DE/ added3,877,361$122M1.8%2026-Q1
Boston Trust Walden Corp trimmed3,227,906$102M1.5%2026-Q1
GOLDMAN SACHS GROUP INC added3,131,348$99M1.4%2026-Q1
VICTORY CAPITAL MANAGEMENT INC trimmed3,091,053$98M1.4%2026-Q1
ALLIANCEBERNSTEIN L.P. trimmed4,451,242$97M1.4%2026-Q1
GW&K Investment Management, LLC trimmed3,081,264$97M1.4%2026-Q1
MORGAN STANLEY added3,027,975$96M1.4%2026-Q1
SYSTEMATIC FINANCIAL MANAGEMENT LP trimmed2,813,278$89M1.3%2026-Q1
SILVERCREST ASSET MANAGEMENT GROUP LLC trimmed2,666,648$84M1.2%2026-Q1
CHARLES SCHWAB INVESTMENT MANAGEMENT INC added2,613,478$83M1.2%2026-Q1
Allspring Global Investments Holdings, LLC trimmed2,699,004$81M1.2%2026-Q1
Nuveen, LLC added2,253,068$71M1.0%2026-Q1
LOOMIS SAYLES & CO L P trimmed2,179,644$69M1.0%2026-Q1
Stephens Investment Management Group LLC added2,172,120$69M1.0%2026-Q1
NORTHERN TRUST CORP added2,132,100$67M1.0%2026-Q1
Bank of New York Mellon Corp trimmed1,943,586$61M0.9%2026-Q1
RENAISSANCE TECHNOLOGIES LLC added1,701,802$54M0.8%2026-Q1
TWO SIGMA INVESTMENTS, LP added1,693,795$53M0.8%2026-Q1
WESTWOOD HOLDINGS GROUP INC trimmed1,590,570$50M0.7%2026-Q1
PRINCIPAL FINANCIAL GROUP INC trimmed1,544,274$49M0.7%2026-Q1
MANUFACTURERS LIFE INSURANCE COMPANY, THE trimmed1,534,372$48M0.7%2026-Q1
BESSEMER GROUP INC added1,254,441$40M0.6%2026-Q1
JPMORGAN CHASE & CO added1,200,481$39M0.6%2026-Q1
FRED ALGER MANAGEMENT, LLC added1,195,380$38M0.6%2026-Q1
VANGUARD FIDUCIARY TRUST CO new1,181,924$37M0.5%2026-Q1
UBS Group AG added1,170,209$37M0.5%2026-Q1
VOLORIDGE INVESTMENT MANAGEMENT, LLC added983,876$31M0.5%2026-Q1
FIRST TRUST ADVISORS LP added976,356$31M0.5%2026-Q1
SIR Capital Management, L.P. trimmed851,094$27M0.4%2026-Q1
Public Sector Pension Investment Board added801,757$25M0.4%2026-Q1
Aberdeen Group plc added768,072$24M0.4%2026-Q1
Point72 Asset Management, L.P. added692,589$22M0.3%2026-Q1
HEARTLAND ADVISORS INC trimmed630,475$20M0.3%2026-Q1
MILLENNIUM MANAGEMENT LLC added599,017$19M0.3%2026-Q1
RHUMBLINE ADVISERS added577,269$18M0.3%2026-Q1
Invesco Ltd. trimmed538,494$17M0.2%2026-Q1
ALGERT GLOBAL LLC added523,620$17M0.2%2026-Q1
AQR CAPITAL MANAGEMENT LLC added490,722$15M0.2%2026-Q1
GILDER GAGNON HOWE & CO LLC trimmed486,526$15M0.2%2026-Q1
SEI INVESTMENTS CO added455,352$14M0.2%2026-Q1
Squarepoint Ops LLC added454,853$14M0.2%2026-Q1
OBERWEIS ASSET MANAGEMENT INC/ added454,466$14M0.2%2026-Q1
Creative Planning added430,579$14M0.2%2026-Q1
ENVESTNET ASSET MANAGEMENT INC added422,086$13M0.2%2026-Q1
NEUBERGER BERMAN GROUP LLC added418,247$13M0.2%2026-Q1
California Public Employees Retirement System added413,997$13M0.2%2026-Q1
Corigliano Investment Advisers, LLC trimmed398,000$13M0.2%2026-Q1
STATE OF WISCONSIN INVESTMENT BOARD trimmed386,531$12M0.2%2026-Q1
Legal & General Group Plc trimmed385,963$12M0.2%2026-Q1
Foster Victor Wealth Advisors, LLC added424,272$12M0.2%2026-Q1
BARROW HANLEY MEWHINNEY & STRAUSS LLC added381,899$12M0.2%2026-Q1
NORDEA INVESTMENT MANAGEMENT AB trimmed362,828$12M0.2%2026-Q1
CITADEL ADVISORS LLC added364,172$11M0.2%2026-Q1
Edgestream Partners, L.P. added352,998$11M0.2%2026-Q1
Swiss National Bank added348,300$11M0.2%2026-Q1
DIAMOND HILL CAPITAL MANAGEMENT INC trimmed325,021$10M0.2%2026-Q1
AMERIPRISE FINANCIAL INC trimmed301,877$10M0.1%2026-Q1
RAYMOND JAMES FINANCIAL INC added283,586$9M0.1%2026-Q1
JANE STREET GROUP, LLC trimmed277,770$9M0.1%2026-Q1
Universal- Beteiligungs- und Servicegesellschaft mbH trimmed275,307$9M0.1%2026-Q1
HRT FINANCIAL LP trimmed273,438$9M0.1%2026-Q1
Trexquant Investment LP trimmed258,646$8M0.1%2026-Q1
BNP PARIBAS FINANCIAL MARKETS added251,446$8M0.1%2026-Q1
Connor, Clark & Lunn Investment Management Ltd. trimmed249,319$8M0.1%2026-Q1
PRICE T ROWE ASSOCIATES INC /MD/ added244,319$8M0.1%2026-Q1
Rafferty Asset Management, LLC added239,979$8M0.1%2026-Q1
Campbell & CO Investment Adviser LLC added237,440$7M0.1%2026-Q1
PRUDENTIAL FINANCIAL INC added234,640$7M0.1%2026-Q1
KING LUTHER CAPITAL MANAGEMENT CORP trimmed232,258$7M0.1%2026-Q1
FRANKLIN RESOURCES INC added225,326$7M0.1%2026-Q1
DEUTSCHE BANK AG\ trimmed220,201$7M0.1%2026-Q1
Russell Investments Group, Ltd. added219,103$7M0.1%2026-Q1
VANGUARD GROUP INC trimmed19,386,295$424M6.2%2025-Q4 stale
MACQUARIE GROUP LTD trimmed5,381,675$128M1.9%2025-Q3 stale
WELLINGTON MANAGEMENT GROUP LLP trimmed5,206,612$114M1.7%2025-Q4 stale
Encompass Capital Advisors LLC added2,182,088$52M0.8%2025-Q3 stale
EnerVest, Ltd.2,099,403$50M0.7%2025-Q3 stale
HITE Hedge Asset Management LLC added1,454,388$32M0.5%2025-Q4 stale
VALLEY WEALTH MANAGERS, INC. trimmed715,217$16M0.2%2025-Q2 stale
Brandywine Global Investment Management, LLC trimmed731,423$16M0.2%2025-Q4 stale
TimesSquare Capital Management, LLC added691,959$16M0.2%2025-Q2 stale
Jefferies Financial Group Inc. added614,682$13M0.2%2025-Q4 stale
Pacer Advisors, Inc. trimmed589,486$13M0.2%2025-Q4 stale
Ranger Investment Management, L.P. trimmed560,990$13M0.2%2025-Q2 stale
CAMBIAR INVESTORS LLC trimmed489,866$12M0.2%2025-Q1 stale
Aventail Capital Group, LP added400,928$10M0.1%2025-Q3 stale
OSTERWEIS CAPITAL MANAGEMENT INC trimmed325,647$7M0.1%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.

HoldersTotal shares

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.

Learn how to read institutional ownership