Allegro MicroSystems, Inc.
MX ˙ BMV ˙ US01749D1054
SecurityMX:ALGM / Allegro MicroSystems, Inc.
InstitutionRhumbline Advisers
Latest Disclosed Ownership308,407 shares
Latest Disclosed Value $ 9,724,037
Rhumbline Advisers reports 2.73% increase in ownership of ALGM / Allegro MicroSystems, Inc.

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 308,407 shares of Allegro MicroSystems, Inc. (MX:ALGM) valued at $9,724,037 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 300,215 shares of Allegro MicroSystems, Inc.. This represents a change in shares of 2.73% 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)
2026-05-12 2026-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 308,407 8,192 2.73 9,724 22.79 0.0083
2026-02-13 2025-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 300,215 -12,709 -4.06 7,920 -13.33 0.0064
2025-11-06 2025-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 312,924 -16,946 -5.14 9,137 -18.98 0.0073
2025-08-12 2025-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 329,870 -393 -0.12 11,278 35.90 0.0097
2025-05-29 2025-03-31 13F/A-1 ALLEGRO MICROSYSTEMS COM 01749D105 330,263 4,428 1.36 8,299 16.53 0.0078
2025-04-08 2025-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 330,263 4,428 8,299 0.0078
2025-05-29 2024-12-31 13F/A-1 ALLEGRO MICROSYSTEMS COM 01749D105 325,835 -37,279 -10.27 7,123 -15.82 0.0064
2025-01-30 2024-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 325,835 -37,279 7,123 0.0064
2024-11-12 2024-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 363,114 163,857 82.23 8,461 50.37 0.0076
2024-08-01 2024-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 199,257 -7,891 -3.81 5,627 0.75 0.0053
2024-05-09 2024-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 207,148 -7,965 -3.70 5,585 -14.24 0.0054
2024-02-08 2023-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 215,113 -4,047 -1.85 6,511 -6.97 0.0068
2023-11-09 2023-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 219,160 17,463 8.66 7,000 -23.12 0.0081
2023-08-08 2023-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 201,697 4,520 2.29 9,105 101,055.56 0.0102
2023-05-11 2023-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 197,177 5,873 3.07 9 -99.84 0.0117
2023-02-14 2022-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 191,304 126,892 197.00 5,743 308.17 0.0077
2022-11-10 2022-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 64,412 17,344 36.85 1,407 44.46 0.0021
2022-08-11 2022-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 47,068 11,534 32.46 974 -3.47 0.0014
2022-05-12 2022-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 35,534 -3,892 -9.87 1,009 -29.24 0.0013
2022-02-10 2021-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 39,426 -1,668 -4.06 1,426 8.61 0.0017
2021-11-12 2021-09-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 41,094 -3,837 -8.54 1,313 5.46 0.0018
2021-08-05 2021-06-30 13F ALLEGRO MICROSYSTEMS COM 01749D105 44,931 7,412 19.76 1,245 30.91 0.0016
2021-05-06 2021-03-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 37,519 18,315 95.37 951 85.74 0.0013
2021-02-10 2020-12-31 13F ALLEGRO MICROSYSTEMS COM 01749D105 19,204 19,204 512 0.0007
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.