Who owns Allegro MicroSystems (ALGM)
Which tracked institutional funds hold ALGM, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ALGM company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 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 ALGM is one-sided between 2026-Q1 and 2026-Q2: 175 added or opened and 53 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
ALGM’s largest tracked holder by dollar value, FMR LLC, sizes it at 0.1% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.1pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in ALGM 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 2026-Q1 and 2026-Q2, across 347 tracked filers holding ALGM, 204 increased or opened the position and 170 reduced or closed it; over the same quarter, open-market insider Form 4s were net sales.
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 ALGM between the 2026-Q1 and 2026-Q2 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 28
- BRAUN STACEY ASSOCIATES INC$26M
- CIBC Bancorp USA Inc.$23M
- Granite Investment Partners, LLC$15M
- Nippon Life Global Investors Americas, Inc.$10M
- Lisanti Capital Growth, LLC$8M
- Edgestream Partners, L.P.$6M
Full exits 35
- Pacer Advisors, Inc.$119M
- GW&K Investment Management, LLC$21M
- T. Rowe Price Investment Management, Inc.$18M
- LORD, ABBETT & CO. LLC$17M
- CITADEL ADVISORS LLC$10M
- HRT FINANCIAL LP$8M
Largest adds
- FMR LLC$917M
- BlackRock, Inc.$747M
- Invesco Ltd.$695M
- JPMORGAN CHASE & CO$602M
- Capital Research Global Investors$444M
- VANGUARD PORTFOLIO MANAGEMENT LLC$284M
Largest trims
- MARSHALL WACE, LLP$22M
- SEGALL BRYANT & HAMILL, LLC$12M
- JACOBS LEVY EQUITY MANAGEMENT, INC$8M
- SIRIOS CAPITAL MANAGEMENT L P$8M
- ALLIANCEBERNSTEIN L.P.$8M
- Walleye Capital LLC$4M
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| FMR LLC trimmed | 25,581,021 | $1.8B | 18.0% | 2026-Q2 |
| BlackRock, Inc. added | 13,889,324 | $967M | 9.8% | 2026-Q2 |
| Invesco Ltd. added | 13,678,393 | $952M | 9.6% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 12,723,790 | $845M | 8.5% | 2026-Q2 |
| Capital Research Global Investors trimmed | 12,006,396 | $836M | 8.4% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC trimmed | 7,668,472 | $534M | 5.4% | 2026-Q2 |
| STATE STREET CORP added | 5,676,421 | $395M | 4.0% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 5,508,806 | $384M | 3.9% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 3,710,288 | $258M | 2.6% | 2026-Q2 |
| Clearbridge Investments, LLC added | 2,946,239 | $205M | 2.1% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 2,644,929 | $184M | 1.9% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 2,123,963 | $148M | 1.5% | 2026-Q2 |
| MORGAN STANLEY trimmed | 1,809,335 | $126M | 1.3% | 2026-Q2 |
| LOOMIS SAYLES & CO L P trimmed | 1,619,931 | $113M | 1.1% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 1,575,057 | $110M | 1.1% | 2026-Q2 |
| PRINCIPAL FINANCIAL GROUP INC trimmed | 1,489,791 | $104M | 1.0% | 2026-Q2 |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ added | 1,443,495 | $100M | 1.0% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 1,360,525 | $95M | 1.0% | 2026-Q2 |
| NORGES BANK added | 1,294,958 | $90M | 0.9% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. trimmed | 1,201,203 | $38M | 0.4% | 2026-Q2 |
| NORTHERN TRUST CORP added | 1,167,135 | $81M | 0.8% | 2026-Q2 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed | 1,159,503 | $81M | 0.8% | 2026-Q2 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 1,121,950 | $78M | 0.8% | 2026-Q2 |
| VOYA INVESTMENT MANAGEMENT LLC trimmed | 966,871 | $67M | 0.7% | 2026-Q2 |
| RAYMOND JAMES FINANCIAL INC trimmed | 928,060 | $65M | 0.7% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 921,728 | $64M | 0.6% | 2026-Q2 |
| WELLINGTON MANAGEMENT GROUP LLP added | 814,937 | $57M | 0.6% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 800,030 | $56M | 0.6% | 2026-Q2 |
| UBS Group AG added | 780,945 | $54M | 0.5% | 2026-Q2 |
| Nuveen, LLC trimmed | 722,645 | $50M | 0.5% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 716,952 | $50M | 0.5% | 2026-Q2 |
| KENNEDY CAPITAL MANAGEMENT LLC trimmed | 689,668 | $48M | 0.5% | 2026-Q2 |
| FIRST TRUST ADVISORS LP added | 684,022 | $48M | 0.5% | 2026-Q2 |
| Allspring Global Investments Holdings, LLC added | 620,540 | $39M | 0.4% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC added | 608,793 | $43M | 0.4% | 2026-Q2 |
| SILVERCREST ASSET MANAGEMENT GROUP LLC trimmed | 537,082 | $37M | 0.4% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC added | 493,753 | $33M | 0.3% | 2026-Q2 |
| Aperture Investors, LLC trimmed | 443,427 | $31M | 0.3% | 2026-Q2 |
| BRAUN STACEY ASSOCIATES INC new | 366,493 | $26M | 0.3% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP trimmed | 343,994 | $24M | 0.2% | 2026-Q2 |
| RHUMBLINE ADVISERS added | 333,507 | $23M | 0.2% | 2026-Q2 |
| S SQUARED TECHNOLOGY, LLC trimmed | 332,451 | $23M | 0.2% | 2026-Q2 |
| SEGALL BRYANT & HAMILL, LLC trimmed | 332,440 | $23M | 0.2% | 2026-Q2 |
| FRONTIER CAPITAL MANAGEMENT CO LLC added | 330,904 | $23M | 0.2% | 2026-Q2 |
| CIBC Bancorp USA Inc. new | 327,536 | $23M | 0.2% | 2026-Q2 |
| Gotham Asset Management, LLC added | 325,436 | $23M | 0.2% | 2026-Q2 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC trimmed | 323,297 | $23M | 0.2% | 2026-Q2 |
| Russell Investments Group, Ltd. added | 272,403 | $19M | 0.2% | 2026-Q2 |
| BALYASNY ASSET MANAGEMENT L.P. added | 267,283 | $19M | 0.2% | 2026-Q2 |
| Swiss National Bank trimmed | 250,900 | $17M | 0.2% | 2026-Q2 |
| FEDERATED HERMES, INC. added | 237,367 | $17M | 0.2% | 2026-Q2 |
| Pier Capital, LLC added | 227,777 | $16M | 0.2% | 2026-Q2 |
| Granite Investment Partners, LLC new | 215,679 | $15M | 0.2% | 2026-Q2 |
| Lightrock Netherlands B.V. trimmed | 206,490 | $14M | 0.1% | 2026-Q2 |
| PEREGRINE CAPITAL MANAGEMENT LLC trimmed | 200,422 | $14M | 0.1% | 2026-Q2 |
| Granahan Investment Management, LLC trimmed | 185,461 | $13M | 0.1% | 2026-Q2 |
| Talos Eurisko Asset Management LP trimmed | 182,600 | $13M | 0.1% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 178,568 | $12M | 0.1% | 2026-Q2 |
| SEI INVESTMENTS CO trimmed | 169,643 | $12M | 0.1% | 2026-Q2 |
| Retirement Systems of Alabama trimmed | 169,402 | $12M | 0.1% | 2026-Q2 |
| Quantinno Capital Management LP added | 166,217 | $12M | 0.1% | 2026-Q2 |
| Legal & General Group Plc added | 164,734 | $11M | 0.1% | 2026-Q2 |
| CITIGROUP INC added | 148,210 | $10M | 0.1% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 144,618 | $10M | 0.1% | 2026-Q2 |
| Nippon Life Global Investors Americas, Inc. new | 143,870 | $10M | 0.1% | 2026-Q2 |
| TRILLIUM ASSET MANAGEMENT, LLC added | 143,348 | $10M | 0.1% | 2026-Q2 |
| CASTLEARK MANAGEMENT LLC trimmed | 141,900 | $10M | 0.1% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 133,903 | $9M | 0.1% | 2026-Q2 |
| VANGUARD ASSET MANAGEMENT, Ltd added | 119,149 | $8M | 0.1% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 108,497 | $8M | 0.1% | 2026-Q2 |
| Lisanti Capital Growth, LLC added | 107,865 | $8M | 0.1% | 2026-Q2 |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM added | 96,177 | $7M | 0.1% | 2026-Q2 |
| Man Group plc trimmed | 95,101 | $7M | 0.1% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 94,917 | $7M | 0.1% | 2026-Q2 |
| Edgestream Partners, L.P. new | 92,188 | $6M | 0.1% | 2026-Q2 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE added | 91,616 | $6M | 0.1% | 2026-Q2 |
| NEW YORK STATE COMMON RETIREMENT FUND added | 89,119 | $6M | 0.1% | 2026-Q2 |
| DEUTSCHE BANK AG\ added | 88,759 | $6M | 0.1% | 2026-Q2 |
| STATE OF WISCONSIN INVESTMENT BOARD trimmed | 88,089 | $6M | 0.1% | 2026-Q2 |
| ENVESTNET ASSET MANAGEMENT INC added | 85,884 | $6M | 0.1% | 2026-Q2 |
| Candriam S.C.A. trimmed | 84,708 | $6M | 0.1% | 2026-Q2 |
| ArrowMark Colorado Holdings LLC trimmed | 83,361 | $6M | 0.1% | 2026-Q2 |
| LPL Financial LLC added | 71,589 | $5M | 0.1% | 2026-Q2 |
| VAN ECK ASSOCIATES CORP added | 70,504 | $5M | 0.0% | 2026-Q2 |
| ALGERT GLOBAL LLC added | 65,240 | $5M | 0.0% | 2026-Q2 |
| JONES FINANCIAL COMPANIES LLLP added | 64,921 | $4M | 0.0% | 2026-Q2 |
| MetLife Investment Management, LLC added | 64,638 | $5M | 0.0% | 2026-Q2 |
| Holocene Advisors, LP added | 63,010 | $4M | 0.0% | 2026-Q2 |
| State of Tennessee, Department of Treasury trimmed | 62,389 | $4M | 0.0% | 2026-Q2 |
| Zurcher Kantonalbank (Zurich Cantonalbank) added | 61,148 | $4M | 0.0% | 2026-Q2 |
| Informed Momentum Co LLC new | 59,485 | $4M | 0.0% | 2026-Q2 |
| GUGGENHEIM CAPITAL LLC added | 59,349 | $4M | 0.0% | 2026-Q2 |
| NEUBERGER BERMAN GROUP LLC added | 59,204 | $4M | 0.0% | 2026-Q2 |
| Jupiter Topco LLC new | 57,329 | $4M | 0.0% | 2026-Q2 |
| Police & Firemen's Retirement System of New Jersey added | 56,462 | $4M | 0.0% | 2026-Q2 |
| NEEDHAM INVESTMENT MANAGEMENT LLC | 55,000 | $4M | 0.0% | 2026-Q2 |
| Munro Partners new | 49,800 | $3M | 0.0% | 2026-Q2 |
| Vanguard Global Advisers, LLC trimmed | 48,314 | $3M | 0.0% | 2026-Q2 |
| Sphera Management Technology Funds Ltd trimmed | 47,550 | $3M | 0.0% | 2026-Q2 |
| MUTUAL OF AMERICA CAPITAL MANAGEMENT LLC trimmed | 46,126 | $3M | 0.0% | 2026-Q2 |
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.