Who owns MAGN (MAGN)
Which tracked institutional funds hold MAGN, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See MAGN 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 MAGN is one-sided between 2025-Q4 and 2026-Q1: 20 added or opened and 64 trimmed or exited — on balance reducing.
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
MAGN’s largest tracked holder by dollar value, VANGUARD GROUP 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 MAGN more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in MAGN 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 178 tracked filers holding MAGN, 88 increased or opened the position and 95 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
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 MAGN 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 8
- VANGUARD CAPITAL MANAGEMENT LLC$15M
- THOMPSON SIEGEL & WALMSLEY LLC$5M
- VANGUARD PORTFOLIO MANAGEMENT LLC$3M
- AMERICAN CENTURY COMPANIES INC$2M
- VANGUARD FIDUCIARY TRUST CO$2M
- AQR CAPITAL MANAGEMENT LLC$1M
Full exits 9
- VANGUARD GROUP INC$28M
- Jefferies Financial Group Inc.$15M
- SG Americas Securities, LLC$8M
- JANE STREET GROUP, LLC$3M
- ARISTEIA CAPITAL, L.L.C.$954K
- Counterpoint Mutual Funds LLC$824K
Largest adds
- DG Capital Management, LLC$11M
- JPMORGAN CHASE & CO$4M
- BRIDGEWAY CAPITAL MANAGEMENT, LLC$729K
- DIMENSIONAL FUND ADVISORS LP$566K
- STATE OF WISCONSIN INVESTMENT BOARD$530K
- READYSTATE ASSET MANAGEMENT LP$498K
Largest trims
- MORGAN STANLEY$18M
- LITTLEJOHN & CO LLC$16M
- BlackRock, Inc.$13M
- Engine Capital Management, LP$13M
- Madison Avenue Partners, LP$12M
- Nuveen, LLC$12M
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 |
|---|---|---|---|---|
| Newtyn Management, LLC added | 2,760,000 | $26M | 5.2% | 2026-Q1 |
| LITTLEJOHN & CO LLC trimmed | 2,425,818 | $23M | 4.5% | 2026-Q1 |
| BlackRock, Inc. added | 2,390,007 | $23M | 4.5% | 2026-Q1 |
| Engine Capital Management, LP | 2,243,827 | $21M | 4.2% | 2026-Q1 |
| MORGAN STANLEY trimmed | 1,967,831 | $19M | 3.7% | 2026-Q1 |
| Madison Avenue Partners, LP trimmed | 1,590,616 | $15M | 3.0% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,533,277 | $15M | 2.9% | 2026-Q1 |
| DG Capital Management, LLC added | 1,207,356 | $11M | 2.3% | 2026-Q1 |
| Diameter Capital Partners LP | 1,205,793 | $11M | 2.3% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 896,215 | $9M | 1.7% | 2026-Q1 |
| CANYON CAPITAL ADVISORS LLC | 810,000 | $8M | 1.5% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 828,799 | $7M | 1.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 780,258 | $7M | 1.5% | 2026-Q1 |
| Assenagon Asset Management S.A. | 742,425 | $7M | 1.4% | 2026-Q1 |
| Clearline Capital LP added | 738,317 | $7M | 1.4% | 2026-Q1 |
| Ancora Advisors LLC added | 721,090 | $7M | 1.3% | 2026-Q1 |
| STATE STREET CORP added | 656,868 | $6M | 1.2% | 2026-Q1 |
| JB CAPITAL PARTNERS LP added | 655,000 | $6M | 1.2% | 2026-Q1 |
| THOMPSON SIEGEL & WALMSLEY LLC new | 574,264 | $5M | 1.1% | 2026-Q1 |
| JACOBS LEVY EQUITY MANAGEMENT, INC trimmed | 524,890 | $5M | 1.0% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 508,525 | $5M | 1.0% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 507,447 | $5M | 0.9% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 453,697 | $4M | 0.8% | 2026-Q1 |
| Verition Fund Management LLC added | 432,303 | $4M | 0.8% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 393,615 | $4M | 0.7% | 2026-Q1 |
| J. Goldman & Co LP trimmed | 387,281 | $4M | 0.7% | 2026-Q1 |
| Seven Six Capital Management, LLC added | 374,868 | $4M | 0.7% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 362,999 | $3M | 0.7% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 314,819 | $3M | 0.6% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 314,409 | $3M | 0.6% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 304,910 | $3M | 0.6% | 2026-Q1 |
| Loews Corp | 300,000 | $3M | 0.6% | 2026-Q1 |
| GRATIA CAPITAL, LLC trimmed | 299,627 | $3M | 0.6% | 2026-Q1 |
| UBS Group AG trimmed | 294,146 | $3M | 0.5% | 2026-Q1 |
| Trexquant Investment LP added | 287,304 | $3M | 0.5% | 2026-Q1 |
| TUDOR INVESTMENT CORP ET AL added | 269,250 | $3M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 254,574 | $2M | 0.5% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 253,908 | $2M | 0.5% | 2026-Q1 |
| LSV ASSET MANAGEMENT trimmed | 244,493 | $2M | 0.5% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC new | 221,133 | $2M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 216,581 | $2M | 0.4% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 202,888 | $2M | 0.4% | 2026-Q1 |
| READYSTATE ASSET MANAGEMENT LP added | 202,213 | $2M | 0.4% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 199,969 | $2M | 0.4% | 2026-Q1 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC added | 198,883 | $2M | 0.4% | 2026-Q1 |
| Man Group plc added | 185,430 | $2M | 0.3% | 2026-Q1 |
| CastleKnight Management LP | 183,495 | $2M | 0.3% | 2026-Q1 |
| Squarepoint Ops LLC added | 177,878 | $2M | 0.3% | 2026-Q1 |
| Jump Financial, LLC added | 173,262 | $2M | 0.3% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 144,473 | $1M | 0.3% | 2026-Q1 |
| Empowered Funds, LLC added | 134,037 | $1M | 0.3% | 2026-Q1 |
| Engineers Gate Manager LP added | 121,427 | $1M | 0.2% | 2026-Q1 |
| Bank of New York Mellon Corp added | 121,035 | $1M | 0.2% | 2026-Q1 |
| Weiss Asset Management LP trimmed | 117,506 | $1M | 0.2% | 2026-Q1 |
| Invesco Ltd. trimmed | 113,877 | $1M | 0.2% | 2026-Q1 |
| ING GROEP NV | 110,000 | $1M | 0.2% | 2026-Q1 |
| XTX Topco Ltd added | 102,976 | $979K | 0.2% | 2026-Q1 |
| Alpine Global Management, LLC added | 100,000 | $951K | 0.2% | 2026-Q1 |
| Nuveen, LLC trimmed | 90,724 | $863K | 0.2% | 2026-Q1 |
| Susquehanna Portfolio Strategies, LLC added | 89,211 | $848K | 0.2% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 80,346 | $764K | 0.2% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 78,955 | $751K | 0.1% | 2026-Q1 |
| Y-Intercept (Hong Kong) Ltd added | 78,572 | $747K | 0.1% | 2026-Q1 |
| NORGES BANK | 40,433 | $734K | 0.1% | 2026-Q1 |
| Quinn Opportunity Partners LLC trimmed | 75,624 | $719K | 0.1% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP trimmed | 72,180 | $686K | 0.1% | 2026-Q1 |
| FMR LLC trimmed | 66,807 | $635K | 0.1% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ trimmed | 57,788 | $550K | 0.1% | 2026-Q1 |
| ExodusPoint Capital Management, LP added | 57,671 | $548K | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 1,860,349 | $28M | 5.5% | 2025-Q4 stale |
| Irenic Capital Management LP added | 1,210,829 | $22M | 4.3% | 2025-Q1 stale |
| FULLER & THALER ASSET MANAGEMENT, INC. added | 1,317,215 | $16M | 3.1% | 2025-Q2 stale |
| Jefferies Financial Group Inc. added | 994,619 | $15M | 3.0% | 2025-Q4 stale |
| SCOPIA CAPITAL MANAGEMENT LP added | 1,010,794 | $12M | 2.4% | 2025-Q2 stale |
| LOOMIS SAYLES & CO L P added | 604,734 | $11M | 2.2% | 2025-Q1 stale |
| BLACK DIAMOND CAPITAL MANAGEMENT, L.L.C. | 750,000 | $9M | 1.8% | 2025-Q2 stale |
| Black Diamond Capital Management I, LLLP new | 750,000 | $9M | 1.7% | 2025-Q3 stale |
| SG Americas Securities, LLC added | 557,810 | $8M | 1.7% | 2025-Q4 stale |
| BRIGHTLINE CAPITAL MANAGEMENT, LLC added | 560,000 | $7M | 1.3% | 2025-Q3 stale |
| Empyrean Capital Partners, LP trimmed | 436,260 | $5M | 1.0% | 2025-Q3 stale |
| Khrom Capital Management LLC trimmed | 263,647 | $5M | 0.9% | 2025-Q1 stale |
| Bracebridge Capital, LLC new | 316,854 | $4M | 0.7% | 2025-Q3 stale |
| TURTLE CREEK ASSET MANAGEMENT INC. | 314,733 | $4M | 0.7% | 2025-Q3 stale |
| JANE STREET GROUP, LLC added | 215,920 | $3M | 0.6% | 2025-Q4 stale |
| HighVista Strategies LLC trimmed | 87,100 | $1M | 0.2% | 2025-Q3 stale |
| OMERS ADMINISTRATION Corp added | 53,100 | $964K | 0.2% | 2025-Q1 stale |
| ARISTEIA CAPITAL, L.L.C. added | 62,996 | $954K | 0.2% | 2025-Q4 stale |
| LANDSCAPE CAPITAL MANAGEMENT, L.L.C. new | 48,896 | $888K | 0.2% | 2025-Q1 stale |
| Cubist Systematic Strategies, LLC added | 72,455 | $849K | 0.2% | 2025-Q3 stale |
| BOOTHBAY FUND MANAGEMENT, LLC added | 69,265 | $837K | 0.2% | 2025-Q2 stale |
| Counterpoint Mutual Funds LLC new | 54,410 | $824K | 0.2% | 2025-Q4 stale |
| TOCQUEVILLE ASSET MANAGEMENT L.P. trimmed | 70,000 | $820K | 0.2% | 2025-Q3 stale |
| Nebula Research & Development LLC added | 67,682 | $818K | 0.2% | 2025-Q2 stale |
| Swiss National Bank | 61,631 | $722K | 0.1% | 2025-Q3 stale |
| OXFORD ASSET MANAGEMENT LLP new | 42,188 | $639K | 0.1% | 2025-Q4 stale |
| SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC trimmed | 50,544 | $611K | 0.1% | 2025-Q2 stale |
| Jain Global LLC trimmed | 38,869 | $588K | 0.1% | 2025-Q4 stale |
| Thrivent Financial for Lutherans | 48,725 | $588K | 0.1% | 2025-Q2 stale |
| Carlson Capital, L.P. trimmed | 32,100 | $583K | 0.1% | 2025-Q1 stale |
| HRT FINANCIAL LP added | 31,603 | $573K | 0.1% | 2025-Q1 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.