Who owns AMBP
Which tracked institutional funds hold AMBP, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See AMBP 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
28 tracked funds added or opened AMBP while 24 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
AMBP’s largest tracked holder by dollar value, CANYON CAPITAL ADVISORS LLC, sizes it at 6.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 6.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in AMBP 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 220 tracked filers holding AMBP, 109 increased or opened the position and 96 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 AMBP 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 11
- VANGUARD PORTFOLIO MANAGEMENT LLC$8M
- JANE STREET GROUP, LLC$3M
- Qube Research & Technologies Ltd$2M
- ExodusPoint Capital Management, LP$1M
- ALGERT GLOBAL LLC$1M
- CANADA PENSION PLAN INVESTMENT BOARD$839K
Full exits 2
- VANGUARD GROUP INC$8M
- TWO SIGMA ADVISERS, LP$2M
Largest adds
- Weiss Asset Management LP$18M
- DIMENSIONAL FUND ADVISORS LP$3M
- ARROWSTREET CAPITAL, LIMITED PARTNERSHIP$3M
- RENAISSANCE TECHNOLOGIES LLC$3M
- HRT FINANCIAL LP$2M
- MILLENNIUM MANAGEMENT LLC$2M
Largest trims
- MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.$32M
- Monarch Alternative Capital LP$10M
- BARCLAYS PLC$7M
- CANYON CAPITAL ADVISORS LLC$4M
- Diameter Capital Partners LP$4M
- BlackRock, Inc.$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 |
|---|---|---|---|---|
| CANYON CAPITAL ADVISORS LLC trimmed | 11,523,328 | $47M | 8.6% | 2026-Q1 |
| Arini Captial Management Ltd | 11,246,170 | $46M | 8.4% | 2026-Q1 |
| BlackRock, Inc. trimmed | 7,734,868 | $31M | 5.7% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 7,288,484 | $30M | 5.4% | 2026-Q1 |
| PLATINUM EQUITY, LLC | 5,311,164 | $22M | 3.9% | 2026-Q1 |
| PRIVATE MANAGEMENT GROUP INC trimmed | 5,017,236 | $20M | 3.7% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 4,637,767 | $19M | 3.4% | 2026-Q1 |
| Weiss Asset Management LP added | 4,516,338 | $18M | 3.4% | 2026-Q1 |
| Diameter Capital Partners LP trimmed | 4,467,420 | $18M | 3.3% | 2026-Q1 |
| Empyrean Capital Partners, LP | 4,000,000 | $16M | 3.0% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 3,269,861 | $13M | 2.4% | 2026-Q1 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. trimmed | 3,113,033 | $13M | 2.3% | 2026-Q1 |
| Monarch Alternative Capital LP trimmed | 2,955,738 | $12M | 2.2% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 2,894,210 | $12M | 2.2% | 2026-Q1 |
| STATE STREET CORP added | 2,523,440 | $10M | 1.9% | 2026-Q1 |
| Gilman Hill Asset Management, LLC added | 1,994,269 | $8M | 1.5% | 2026-Q1 |
| JACOBS LEVY EQUITY MANAGEMENT, INC trimmed | 1,915,177 | $8M | 1.4% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,883,962 | $8M | 1.4% | 2026-Q1 |
| Mountaineer Partners Management, LLC added | 1,878,082 | $8M | 1.4% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 1,855,236 | $8M | 1.4% | 2026-Q1 |
| Nuveen, LLC added | 1,739,194 | $7M | 1.3% | 2026-Q1 |
| MORGAN STANLEY added | 1,737,926 | $7M | 1.3% | 2026-Q1 |
| UBS Group AG added | 1,487,866 | $6M | 1.1% | 2026-Q1 |
| GAMCO INVESTORS, INC. ET AL trimmed | 1,422,507 | $6M | 1.1% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 1,359,096 | $6M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 1,332,612 | $5M | 1.0% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 1,262,513 | $5M | 0.9% | 2026-Q1 |
| GABELLI FUNDS LLC trimmed | 886,545 | $4M | 0.7% | 2026-Q1 |
| Hillsdale Investment Management Inc. added | 869,063 | $4M | 0.6% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 854,564 | $3M | 0.6% | 2026-Q1 |
| MACKENZIE FINANCIAL CORP added | 839,934 | $3M | 0.6% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 797,842 | $3M | 0.6% | 2026-Q1 |
| HRT FINANCIAL LP added | 797,802 | $3M | 0.6% | 2026-Q1 |
| ROYAL BANK OF CANADA trimmed | 698,443 | $3M | 0.5% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 664,801 | $3M | 0.5% | 2026-Q1 |
| TUDOR INVESTMENT CORP ET AL trimmed | 626,357 | $3M | 0.5% | 2026-Q1 |
| CWA Asset Management Group, LLC added | 614,566 | $2M | 0.5% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 565,942 | $2M | 0.4% | 2026-Q1 |
| MARTINGALE ASSET MANAGEMENT L P added | 558,688 | $2M | 0.4% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 469,946 | $2M | 0.3% | 2026-Q1 |
| Janney Montgomery Scott LLC trimmed | 447,728 | $2M | 0.3% | 2026-Q1 |
| CONTRARIAN CAPITAL MANAGEMENT, L.L.C. | 413,706 | $2M | 0.3% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 407,687 | $2M | 0.3% | 2026-Q1 |
| Invesco Ltd. trimmed | 372,105 | $2M | 0.3% | 2026-Q1 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND | 353,000 | $1M | 0.3% | 2026-Q1 |
| CITIGROUP INC trimmed | 350,644 | $1M | 0.3% | 2026-Q1 |
| ExodusPoint Capital Management, LP added | 313,853 | $1M | 0.2% | 2026-Q1 |
| Point72 Asset Management, L.P. trimmed | 305,666 | $1M | 0.2% | 2026-Q1 |
| ALGERT GLOBAL LLC trimmed | 297,270 | $1M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 292,702 | $1M | 0.2% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC trimmed | 286,634 | $1M | 0.2% | 2026-Q1 |
| Corvex Management LP trimmed | 280,854 | $1M | 0.2% | 2026-Q1 |
| IQ EQ FUND MANAGEMENT (IRELAND) Ltd trimmed | 275,126 | $1M | 0.2% | 2026-Q1 |
| WOLVERINE ASSET MANAGEMENT LLC | 255,899 | $1M | 0.2% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 249,581 | $1M | 0.2% | 2026-Q1 |
| Squarepoint Ops LLC trimmed | 238,117 | $964K | 0.2% | 2026-Q1 |
| Redhawk Wealth Advisors, Inc. trimmed | 228,309 | $925K | 0.2% | 2026-Q1 |
| NORGES BANK | 292,456 | $883K | 0.2% | 2026-Q1 |
| PDT Partners, LLC trimmed | 211,387 | $856K | 0.2% | 2026-Q1 |
| CANADA PENSION PLAN INVESTMENT BOARD new | 207,200 | $839K | 0.2% | 2026-Q1 |
| KESTRA PRIVATE WEALTH SERVICES, LLC added | 201,915 | $818K | 0.2% | 2026-Q1 |
| Integrated Quantitative Investments LLC new | 194,594 | $788K | 0.1% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 192,084 | $755K | 0.1% | 2026-Q1 |
| IEQ CAPITAL, LLC trimmed | 179,162 | $726K | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC added | 178,949 | $725K | 0.1% | 2026-Q1 |
| OCCUDO QUANTITATIVE STRATEGIES LP added | 184,442 | $710K | 0.1% | 2026-Q1 |
| Quantbot Technologies LP added | 170,408 | $690K | 0.1% | 2026-Q1 |
| BARCLAYS PLC trimmed | 169,680 | $687K | 0.1% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 169,315 | $686K | 0.1% | 2026-Q1 |
| TRED AVON FAMILY WEALTH, LLC trimmed | 163,541 | $662K | 0.1% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. | 145,632 | $597K | 0.1% | 2026-Q1 |
| Legato Capital Management LLC new | 147,030 | $595K | 0.1% | 2026-Q1 |
| Essex Financial Services, Inc. trimmed | 144,329 | $585K | 0.1% | 2026-Q1 |
| Dakota Wealth Management trimmed | 141,889 | $575K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 139,617 | $565K | 0.1% | 2026-Q1 |
| Counterpoint Mutual Funds LLC added | 136,732 | $554K | 0.1% | 2026-Q1 |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO trimmed | 131,147 | $531K | 0.1% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 128,955 | $522K | 0.1% | 2026-Q1 |
| Mariner, LLC trimmed | 124,141 | $503K | 0.1% | 2026-Q1 |
| Graham Capital Management, L.P. trimmed | 122,130 | $495K | 0.1% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 111,545 | $452K | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 106,841 | $433K | 0.1% | 2026-Q1 |
| Anchorage Capital Advisors, L.P. | 2,451,062 | $10M | 1.8% | 2025-Q3 stale |
| Solas Capital Management, LLC trimmed | 3,013,910 | $9M | 1.7% | 2025-Q1 stale |
| VANGUARD GROUP INC added | 1,998,456 | $8M | 1.5% | 2025-Q4 stale |
| KING STREET CAPITAL MANAGEMENT, L.P. trimmed | 1,750,000 | $7M | 1.4% | 2025-Q2 stale |
| Anchorage Capital Group, L.L.C. | 1,250,000 | $5M | 0.9% | 2025-Q3 stale |
| Keeley-Teton Advisors, LLC trimmed | 1,599,919 | $5M | 0.9% | 2025-Q1 stale |
| CenterBook Partners LP trimmed | 1,426,004 | $4M | 0.8% | 2025-Q1 stale |
| Shellback Capital, LP new | 951,359 | $4M | 0.7% | 2025-Q2 stale |
| Cubist Systematic Strategies, LLC added | 621,737 | $3M | 0.5% | 2025-Q2 stale |
| Walleye Capital LLC added | 450,523 | $2M | 0.4% | 2025-Q2 stale |
| TWO SIGMA ADVISERS, LP trimmed | 435,700 | $2M | 0.3% | 2025-Q4 stale |
| GRIZZLYROCK CAPITAL, LLC trimmed | 224,162 | $959K | 0.2% | 2025-Q2 stale |
| Jain Global LLC new | 166,221 | $711K | 0.1% | 2025-Q2 stale |
| MARSHALL WACE, LLP trimmed | 158,687 | $479K | 0.1% | 2025-Q1 stale |
| Verition Fund Management LLC | 116,700 | $478K | 0.1% | 2025-Q4 stale |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 106,851 | $457K | 0.1% | 2025-Q2 stale |
| CastleKnight Management LP | 105,500 | $433K | 0.1% | 2025-Q4 stale |
| Man Group plc added | 99,387 | $407K | 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.