Allegro MicroSystems, Inc.
MX ˙ BMV ˙ US01749D1054
SecurityMX:ALGM / Allegro MicroSystems, Inc.
InstitutionAdage Capital Partners Gp, L.l.c.
ManagerPhil Gross, Robert Atchinson
Latest Disclosed Ownership1,464,737 shares
Latest Disclosed Value $ 46,183,158
Adage Capital Partners Gp, L.l.c. reports 47.76% decrease in ownership of ALGM / Allegro MicroSystems, Inc.

On May 15, 2026 - Adage Capital Partners Gp, L.l.c. filed a 13F-HR form disclosing ownership of 1,464,737 shares of Allegro MicroSystems, Inc. (MX:ALGM) valued at $46,183,158 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,803,944 shares of Allegro MicroSystems, Inc.. This represents a change in shares of -47.76% during the quarter.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,464,737 -1,339,207 -47.76 46,183 -37.56 0.0712
2026-02-17 2025-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,803,944 1,227,317 77.84 73,968 60.67 0.1119
2025-11-14 2025-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,576,627 -600,933 -27.60 46,038 -38.16 0.0729
2025-08-14 2025-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,177,560 69,137 3.28 74,451 40.51 0.1255
2025-05-15 2025-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,108,423 -625,137 -22.87 52,985 -11.33 0.0981
2025-02-14 2024-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,733,560 911,993 50.07 59,756 40.79 0.1045
2024-11-14 2024-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,821,567 325,000 21.72 42,443 0.42 0.0749
2024-08-14 2024-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,496,567 398,365 36.27 42,263 42.75 0.0783
2024-05-15 2024-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,098,202 96,615 9.65 29,608 -2.35 0.0559
2024-02-14 2023-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,001,587 540,000 116.99 30,318 105.64 0.0628
2023-11-14 2023-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 461,587 80,000 20.97 14,743 -14.40 0.0334
2023-08-14 2023-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 381,587 143,348 60.17 17,225 50.65 0.0374
2023-05-15 2023-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 238,239 -797,548 -77.00 11,433 -63.23 0.0256
2023-02-14 2022-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,035,787 -1,251,517 -54.72 31,094 -37.78 0.0744
2022-11-14 2022-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,287,304 247,608 12.14 49,978 18.43 0.1240
2022-08-15 2022-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 2,039,696 459,000 29.04 42,201 -5.99 0.0967
2022-05-16 2022-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,580,696 325,342 25.92 44,892 -1.16 0.0853
2022-02-14 2021-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 1,255,354 521,881 71.15 45,419 93.75 0.0818
2021-11-15 2021-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 733,473 254,506 53.14 23,442 76.69 0.0462
2021-08-16 2021-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 478,967 -62,500 -11.54 13,267 -3.34 0.0260
2021-05-17 2021-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 541,467 7,764 1.45 13,726 -3.54 0.0280
2021-02-16 2020-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 533,703 533,703 14,229 0.0310
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.