Who owns MediaAlpha, Inc. (MAX)
Which tracked institutional funds hold MAX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See MAX company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 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
24 tracked funds added or opened MAX while 53 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
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
MAX’s largest tracked holder by dollar value, WHITE MOUNTAINS INSURANCE GROUP LTD, sizes it at 53.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 53.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in MAX 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 163 tracked filers holding MAX, 93 increased or opened the position and 100 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 MAX 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 7
- VANGUARD CAPITAL MANAGEMENT LLC$13M
- VANGUARD PORTFOLIO MANAGEMENT LLC$5M
- SPEECE THORSON CAPITAL GROUP INC$5M
- Philadelphia Financial Management of San Francisco, LLC$4M
- VANGUARD FIDUCIARY TRUST CO$2M
- Caption Management, LLC$1M
Full exits 12
- VANGUARD GROUP INC$30M
- G2 Investment Partners Management LLC$6M
- MARSHALL WACE, LLP$4M
- CANADA PENSION PLAN INVESTMENT BOARD$2M
- BOOTHBAY FUND MANAGEMENT, LLC$1M
- TUDOR INVESTMENT CORP ET AL$1M
Largest adds
- Clearline Capital LP$7M
- Triad Investment Management$6M
- ALLIANCEBERNSTEIN L.P.$2M
- BANK OF AMERICA CORP /DE/$2M
- HRT FINANCIAL LP$2M
- DIMENSIONAL FUND ADVISORS LP$2M
Largest trims
- WHITE MOUNTAINS INSURANCE GROUP LTD$65M
- BlackRock, Inc.$14M
- Divisadero Street Capital Management, LP$10M
- MILLENNIUM MANAGEMENT LLC$9M
- VICTORY CAPITAL MANAGEMENT INC$9M
- RENAISSANCE TECHNOLOGIES LLC$7M
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 |
|---|---|---|---|---|
| WHITE MOUNTAINS INSURANCE GROUP LTD | 17,856,614 | $166M | 30.0% | 2026-Q1 |
| BlackRock, Inc. trimmed | 3,476,687 | $32M | 5.8% | 2026-Q1 |
| Clearline Capital LP added | 2,590,670 | $24M | 4.4% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 1,745,679 | $16M | 3.0% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,385,729 | $13M | 2.3% | 2026-Q1 |
| J. Goldman & Co LP added | 1,182,673 | $11M | 2.0% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,070,084 | $10M | 1.8% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 1,061,981 | $10M | 1.8% | 2026-Q1 |
| Triad Investment Management added | 944,973 | $9M | 1.7% | 2026-Q1 |
| JACOBS ASSET MANAGEMENT, LLC added | 924,443 | $9M | 1.6% | 2026-Q1 |
| Pacer Advisors, Inc. added | 411,340 | $8M | 1.4% | 2026-Q1 |
| ACADIAN ASSET MANAGEMENT LLC added | 847,199 | $8M | 1.4% | 2026-Q1 |
| STATE STREET CORP added | 838,161 | $8M | 1.4% | 2026-Q1 |
| Shay Capital LLC added | 775,000 | $7M | 1.3% | 2026-Q1 |
| JACOBS LEVY EQUITY MANAGEMENT, INC added | 750,054 | $7M | 1.3% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 719,300 | $7M | 1.2% | 2026-Q1 |
| MORGAN STANLEY trimmed | 703,018 | $7M | 1.2% | 2026-Q1 |
| Nuveen, LLC added | 701,399 | $7M | 1.2% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 623,421 | $6M | 1.0% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 620,669 | $6M | 1.0% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 546,745 | $5M | 0.9% | 2026-Q1 |
| SPEECE THORSON CAPITAL GROUP INC new | 499,011 | $5M | 0.8% | 2026-Q1 |
| Philadelphia Financial Management of San Francisco, LLC added | 480,000 | $4M | 0.8% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 467,413 | $4M | 0.8% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 415,280 | $4M | 0.7% | 2026-Q1 |
| FRANKLIN RESOURCES INC added | 343,709 | $3M | 0.6% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 342,058 | $3M | 0.6% | 2026-Q1 |
| HRT FINANCIAL LP added | 329,332 | $3M | 0.6% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. added | 205,440 | $3M | 0.5% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 283,008 | $3M | 0.5% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 279,704 | $3M | 0.5% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 274,339 | $3M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 271,824 | $3M | 0.5% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 229,323 | $2M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 227,112 | $2M | 0.4% | 2026-Q1 |
| PARADIGM ASSET MANAGEMENT CO LLC | 139,900 | $2M | 0.4% | 2026-Q1 |
| Stoic Point Capital Management LLC added | 221,041 | $2M | 0.4% | 2026-Q1 |
| Squarepoint Ops LLC added | 215,541 | $2M | 0.4% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 189,736 | $2M | 0.3% | 2026-Q1 |
| TEACHER RETIREMENT SYSTEM OF TEXAS added | 185,325 | $2M | 0.3% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 180,511 | $2M | 0.3% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 175,289 | $2M | 0.3% | 2026-Q1 |
| Y-Intercept (Hong Kong) Ltd trimmed | 158,170 | $1M | 0.3% | 2026-Q1 |
| UBS Group AG added | 153,883 | $1M | 0.3% | 2026-Q1 |
| Caption Management, LLC added | 149,048 | $1M | 0.3% | 2026-Q1 |
| XTX Topco Ltd added | 146,838 | $1M | 0.2% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 137,613 | $1M | 0.2% | 2026-Q1 |
| Man Group plc added | 136,707 | $1M | 0.2% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP added | 109,268 | $1M | 0.2% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 108,808 | $1M | 0.2% | 2026-Q1 |
| Quantinno Capital Management LP added | 107,274 | $998K | 0.2% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 106,160 | $987K | 0.2% | 2026-Q1 |
| PDT Partners, LLC trimmed | 90,022 | $837K | 0.2% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 87,269 | $812K | 0.1% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 86,955 | $809K | 0.1% | 2026-Q1 |
| Divisadero Street Capital Management, LP trimmed | 86,907 | $808K | 0.1% | 2026-Q1 |
| Russell Investments Group, Ltd. trimmed | 84,894 | $794K | 0.1% | 2026-Q1 |
| ALGERT GLOBAL LLC trimmed | 84,510 | $786K | 0.1% | 2026-Q1 |
| GLOBEFLEX CAPITAL L P | 80,233 | $746K | 0.1% | 2026-Q1 |
| Amundi added | 78,104 | $726K | 0.1% | 2026-Q1 |
| Allianz Asset Management GmbH | 70,176 | $653K | 0.1% | 2026-Q1 |
| Swiss National Bank | 58,700 | $546K | 0.1% | 2026-Q1 |
| Mariner, LLC trimmed | 58,489 | $544K | 0.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 56,206 | $523K | 0.1% | 2026-Q1 |
| BLAIR WILLIAM & CO/IL trimmed | 55,975 | $521K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 47,884 | $445K | 0.1% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 47,041 | $437K | 0.1% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC added | 47,885 | $435K | 0.1% | 2026-Q1 |
| BARCLAYS PLC trimmed | 45,364 | $422K | 0.1% | 2026-Q1 |
| Dynamic Technology Lab Private Ltd added | 43,595 | $405K | 0.1% | 2026-Q1 |
| State of Wyoming added | 43,001 | $400K | 0.1% | 2026-Q1 |
| Brooklyn Investment Group added | 39,724 | $369K | 0.1% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 37,688 | $350K | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 2,306,750 | $30M | 5.4% | 2025-Q4 stale |
| Broad Bay Capital Management, LP trimmed | 1,468,695 | $17M | 3.0% | 2025-Q3 stale |
| TimesSquare Capital Management, LLC trimmed | 1,372,174 | $13M | 2.3% | 2025-Q1 stale |
| G2 Investment Partners Management LLC added | 496,916 | $6M | 1.2% | 2025-Q4 stale |
| MARSHALL WACE, LLP added | 328,388 | $4M | 0.8% | 2025-Q4 stale |
| Hillsdale Investment Management Inc. added | 359,200 | $4M | 0.7% | 2025-Q2 stale |
| LAZARD ASSET MANAGEMENT LLC trimmed | 294,796 | $3M | 0.6% | 2025-Q3 stale |
| EARNEST PARTNERS LLC | 269,607 | $3M | 0.6% | 2025-Q3 stale |
| Jackson Creek Investment Advisors LLC added | 164,060 | $2M | 0.3% | 2025-Q2 stale |
| CANADA PENSION PLAN INVESTMENT BOARD added | 136,500 | $2M | 0.3% | 2025-Q4 stale |
| BOOTHBAY FUND MANAGEMENT, LLC added | 108,143 | $1M | 0.3% | 2025-Q4 stale |
| Trexquant Investment LP added | 120,775 | $1M | 0.2% | 2025-Q2 stale |
| TUDOR INVESTMENT CORP ET AL added | 83,330 | $1M | 0.2% | 2025-Q4 stale |
| NOMURA HOLDINGS INC added | 82,313 | $1M | 0.2% | 2025-Q4 stale |
| Lighthouse Investment Partners, LLC trimmed | 82,050 | $1M | 0.2% | 2025-Q4 stale |
| ExodusPoint Capital Management, LP trimmed | 81,791 | $1M | 0.2% | 2025-Q4 stale |
| Janney Montgomery Scott LLC trimmed | 70,355 | $801K | 0.1% | 2025-Q3 stale |
| RAYMOND JAMES FINANCIAL INC added | 52,708 | $683K | 0.1% | 2025-Q4 stale |
| HSBC HOLDINGS PLC added | 51,550 | $561K | 0.1% | 2025-Q2 stale |
| Verition Fund Management LLC trimmed | 39,303 | $509K | 0.1% | 2025-Q4 stale |
| Semanteon Capital Management, LP added | 44,583 | $507K | 0.1% | 2025-Q3 stale |
| Gotham Asset Management, LLC trimmed | 39,123 | $507K | 0.1% | 2025-Q4 stale |
| AlphaQuest LLC added | 37,463 | $485K | 0.1% | 2025-Q4 stale |
| Thrivent Financial for Lutherans added | 36,379 | $471K | 0.1% | 2025-Q4 stale |
| PharVision Advisers, LLC added | 34,034 | $441K | 0.1% | 2025-Q4 stale |
| Versor Investments LP new | 29,318 | $380K | 0.1% | 2025-Q4 stale |
| Jain Global LLC added | 31,143 | $354K | 0.1% | 2025-Q3 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.