Allegro MicroSystems, Inc. (ALGM) Ownership
ALGM ownership summary
as of October 18, 2026- Institutions
- 80.8% of shares outstanding
- Insiders
- 32.54% of shares outstanding
- Shares outstanding
- 186.4M
- Float
- 125.0M shares available to trade
- Short interest
- 11.57% 11.4M shares short
- Days to cover
- 4.85 short interest up 9.1% vs prior month
- Institutions 80.79%
- Insiders 32.54%
ALGM top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | FMR Inc | 13.72% | 25.6M | $808.9M | −1.8M (−6.7%) | June 30, 2026 |
| 2 | BlackRock Inc | 7.45% | 13.9M | $439.2M | +1.4M (+11.2%) | June 30, 2026 |
| 3 | Amvescap Plc. | 7.34% | 13.7M | $432.5M | +4.9M (+56.3%) | June 30, 2026 |
| 4 | JPMorgan Chase & Co | 6.83% | 12.7M | $402.3M | +4.1M (+47.1%) | June 30, 2026 |
| 5 | Capital Research Global Investors | 6.44% | 12.0M | $379.6M | −429,162 (−3.5%) | June 30, 2026 |
| 6 | Vanguard Portfolio Management, LLC | 4.11% | 7.7M | $242.5M | −251,570 (−3.2%) | June 30, 2026 |
| 7 | State Street Corp | 3.05% | 5.7M | $179.5M | +448,317 (+8.6%) | June 30, 2026 |
| 8 | Vanguard Capital Management, LLC | 2.96% | 5.5M | $174.2M | +44,088 (+0.8%) | June 30, 2026 |
| 9 | T. Rowe Price Associates, Inc. | 1.99% | 3.7M | $117.3M | +3.6M (+3,160.4%) | June 30, 2026 |
| 10 | ClearBridge Advisors, LLC | 1.58% | 2.9M | $93.2M | +82,529 (+2.9%) | June 30, 2026 |
| 11 | Geode Capital Management, LLC | 1.42% | 2.6M | $83.6M | +188,109 (+7.7%) | June 30, 2026 |
| 12 | Dimensional Fund Advisors, Inc. | 1.14% | 2.1M | $67.2M | −46,524 (−2.1%) | June 30, 2026 |
| 13 | Morgan Stanley - Brokerage Accounts | 0.97% | 1.8M | $57.2M | −465,950 (−20.5%) | June 30, 2026 |
| 14 | Loomis, Sayles & Company LP | 0.87% | 1.6M | $51.2M | −54,177 (−3.2%) | June 30, 2026 |
| 15 | The Goldman Sachs Group Inc | 0.84% | 1.6M | $49.8M | +137,842 (+9.6%) | June 30, 2026 |
| 16 | Principal Financial Group Inc | 0.80% | 1.5M | $47.1M | −300,675 (−16.8%) | June 30, 2026 |
| 17 | Massachusetts Financial Services Company | 0.77% | 1.4M | $45.6M | +1.4M (+1,983.1%) | June 30, 2026 |
| 18 | Charles Schwab Investment Management Inc | 0.73% | 1.4M | $43.0M | −30,081 (−2.2%) | June 30, 2026 |
| 19 | NORGES BANK | 0.69% | 1.3M | $40.9M | −162,847 (−11.2%) | June 30, 2026 |
| 20 | AllianceBernstein L.P. | 0.64% | 1.2M | $38.0M | −522,167 (−30.3%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 10 holders added 16.3M shares and 10 cut 4.1M.
ALGM top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Fidelity Select Semiconductors | 6.41% | 12.0M | $378.0M | −3.3M (−21.5%) | August 31, 2026 |
| 2 | American Funds Cptl Wld Gr&Inc A | 3.18% | 5.9M | $187.4M | — | June 30, 2026 |
| 3 | American Funds SMALLCAP World A | 2.95% | 5.5M | $174.0M | −146,825 (−2.6%) | June 30, 2026 |
| 4 | iShares Core S&P Mid-Cap ETF | 2.42% | 4.5M | $142.8M | −1,608 (−0.0%) | September 30, 2026 |
| 5 | Vanguard MStar Total Stk Mkt Idx Invest | 2.07% | 3.8M | $121.7M | −4,771 (−0.1%) | August 31, 2026 |
| 6 | Invesco Small Cap Value A | 1.72% | 3.2M | $101.2M | −1.2M (−27.9%) | August 31, 2026 |
| 7 | T. Rowe Price New Horizons | 1.58% | 2.9M | $93.2M | +1.1M (+55.7%) | August 31, 2026 |
| 8 | Vanguard Small Cap Index | 1.49% | 2.8M | $88.0M | +271 (+0.0%) | August 31, 2026 |
| 9 | Invesco Discovery A | 1.49% | 2.8M | $88.0M | +229,713 (+9.0%) | August 31, 2026 |
| 10 | Vanguard Information Technology ETF | 1.41% | 2.6M | $83.1M | −62,946 (−2.3%) | August 31, 2026 |
| 11 | State Street® SPDR® S&P® Smcndctr ETF | 1.08% | 2.0M | $63.6M | +8,540 (+0.4%) | September 30, 2026 |
| 12 | Fidelity Advisor Semiconductors I | 1.06% | 2.0M | $62.2M | −455,800 (−18.8%) | August 31, 2026 |
| 13 | JPMorgan Growth Advantage A | 1.02% | 1.9M | $60.0M | −27,685 (−1.4%) | August 31, 2026 |
| 14 | Vanguard MStar Small Cap Growth Indx Inv | 0.86% | 1.6M | $50.6M | −10,541 (−0.7%) | August 31, 2026 |
| 15 | JPMorgan Mid Cap Growth I | 0.85% | 1.6M | $50.2M | −29,462 (−1.8%) | August 31, 2026 |
| 16 | JPM US Technology A dist USD | 0.80% | 1.5M | $46.9M | +86,998 (+6.2%) | August 31, 2026 |
| 17 | Vanguard Explorer Inv | 0.69% | 1.3M | $40.6M | — | June 30, 2026 |
| 18 | Invesco Glbl Consmr Trnds A USD Acc | 0.64% | 1.2M | $37.7M | +80,579 (+7.2%) | August 31, 2026 |
| 19 | ClearBridge Small Cap Growth A | 0.53% | 986K | $31.2M | −48,300 (−4.7%) | August 31, 2026 |
| 20 | State Street® SPDR® S&P MIDCAP 400® ETF | 0.49% | 908K | $28.7M | −10,222 (−1.1%) | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ALGM insider transactions
latest 1| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2025-08-22 | Roald Graham Webster | Sell | $32.81 | 8,266 | $271,207 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ALGM shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ALGM
Institutional investors own 80.8% of Allegro MicroSystems's shares and insiders 32.54%. The largest holder is FMR Inc with 13.72% of the shares (25.6M), as of June 30, 2026. Among the top 20 institutions, 10 added shares and 10 reduced their stake in the latest filings. Short interest is 11.57% of the float, or 4.85 days of average trading volume.
Related: ALGM analyst forecast, ALGM key metrics. See the ALGM stock overview for the latest quote and news.
ALGM ownership FAQ
Who owns the most Allegro MicroSystems stock?
The largest shareholders of Allegro MicroSystems are FMR Inc (13.72%), BlackRock Inc (7.45%), Amvescap Plc. (7.34%), JPMorgan Chase & Co (6.83%), Capital Research Global Investors (6.44%).
What percentage of Allegro MicroSystems is owned by institutions?
Institutions hold 80.8% of Allegro MicroSystems's shares outstanding; insiders hold 32.54%.
Which funds own Allegro MicroSystems?
The largest fund holders of Allegro MicroSystems are Fidelity Select Semiconductors (6.41%), American Funds Cptl Wld Gr&Inc A (3.18%), American Funds SMALLCAP World A (2.95%), iShares Core S&P Mid-Cap ETF (2.42%), Vanguard MStar Total Stk Mkt Idx Invest (2.07%).
What is Allegro MicroSystems's short interest?
11.4M shares of Allegro MicroSystems were sold short, 11.57% of the float; at the average daily volume it would take 4.85 days to cover.
Are insiders buying or selling Allegro MicroSystems?
Of the latest 1 reported insider transactions in Allegro MicroSystems (since August 22, 2025), 0 were purchases and 1 were sales.
How many shares of Allegro MicroSystems are outstanding?
Allegro MicroSystems has 186.4M shares outstanding, of which 125.0M are in the public float.