Mayville Engineering Company, Inc.
US ˙ NYSE ˙ US5786051079

SecurityMEC / Mayville Engineering Company, Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership23,834 shares
Latest Disclosed Value $ 427,821
Morgan Stanley reports 71.07% decrease in ownership of MEC / Mayville Engineering Company, Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 23,834 shares of Mayville Engineering Company, Inc. (US:MEC) valued at $427,820 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 82,390 shares of Mayville Engineering Company, Inc.. This represents a change in shares of -71.07% during the quarter. The current value of the position is $778,895 USD.

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 MAYVILLE ENGR COM 578605107 23,834 -58,556 -71.07 428 -72.31 0.0000
2026-05-27 2025-12-31 13F/A-1 MAYVILLE ENGR COM 578605107 82,390 47,389 135.39 1,542 220.58 0.0001
2026-02-13 2025-12-31 13F MAYVILLE ENGR COM 578605107 82,390 47,389 1,542 0.0001
2026-05-27 2025-09-30 13F/A-1 MAYVILLE ENGR COM 578605107 35,001 -27,301 -43.82 482 -51.61 0.0000
2025-11-14 2025-09-30 13F MAYVILLE ENGR COM 578605107 35,001 -27,301 482 0.0000
2025-08-15 2025-06-30 13F MAYVILLE ENGR COM 578605107 62,302 33,451 115.94 994 156.85 0.0001
2025-05-15 2025-03-31 13F MAYVILLE ENGR COM 578605107 28,851 -16,015 -35.70 387 -45.11 0.0000
2025-05-15 2024-12-31 13F/A-1 MAYVILLE ENGR COM 578605107 44,866 -12,584 -21.90 705 -41.78 0.0000
2025-02-14 2024-12-31 13F MAYVILLE ENGR COM 578605107 44,866 -12,584 705 0.0000
2025-05-14 2024-09-30 13F/A-2 MAYVILLE ENGR COM 578605107 57,450 27,059 89.04 1,211 139.33 0.0001
2025-02-14 2024-09-30 13F/A-1 MAYVILLE ENGR COM 578605107 57,450 27,059 1,211 0.0001
2024-11-14 2024-09-30 13F MAYVILLE ENGR COM 578605107 57,450 27,059 1,211 0.0001
2025-05-14 2024-06-30 13F/A-2 MAYVILLE ENGR COM 578605107 30,391 9,273 43.91 506 67.55 0.0000
2024-10-17 2024-06-30 13F/A-1 MAYVILLE ENGR COM 578605107 30,391 9,273 506 0.0000
2024-08-14 2024-06-30 13F MAYVILLE ENGR COM 578605107 30,391 9,273 506 0.0000
2024-10-17 2024-03-31 13F/A-2 MAYVILLE ENGR COM 578605107 21,118 -6,540 -23.65 303 -24.12 0.0000
2024-08-16 2024-03-31 13F/A-1 MAYVILLE ENGR COM 578605107 21,118 -6,540 303 0.0000
2024-05-15 2024-03-31 13F MAYVILLE ENGR COM 578605107 21,118 -6,540 303 0.0000
2024-08-16 2023-12-31 13F/A-1 MAYVILLE ENGR COM 578605107 27,658 14,123 104.34 399 168.92 0.0000
2024-02-13 2023-12-31 13F MAYVILLE ENGR COM 578605107 27,658 14,123 399 0.0000
2023-11-15 2023-09-30 13F MAYVILLE ENGR COM 578605107 13,535 377 2.87 148 -9.20 0.0000
2023-08-14 2023-06-30 13F MAYVILLE ENGR COM 578605107 13,158 -140,867 -91.46 164 -92.91 0.0000
2023-05-15 2023-03-31 13F MAYVILLE ENGR COM 578605107 154,025 124,600 423.45 2,298 517.74 0.0002
2023-02-14 2022-12-31 13F MAYVILLE ENGR COM 578605107 29,425 -6,154 -17.30 373 60.34 0.0000
2022-11-14 2022-09-30 13F MAYVILLE ENGR COM 578605107 35,579 9,466 36.25 232 14.29 0.0000
2022-10-27 2022-06-30 13F/A-1 MAYVILLE ENGR COM 578605107 26,113 11,395 77.42 203 46.04 0.0000
2022-08-15 2022-06-30 13F MAYVILLE ENGR COM 578605107 26,113 11,395 203 0.0000
2022-10-27 2022-03-31 13F/A-1 MAYVILLE ENGR COM 578605107 14,718 -9,077 -38.15 139 -60.73 0.0000
2022-05-13 2022-03-31 13F MAYVILLE ENGR COM 578605107 14,718 -9,077 139 0.0000
2022-02-14 2021-12-31 13F MAYVILLE ENGR COM 578605107 23,795 7,985 50.51 354 18.79 0.0000
2021-11-15 2021-09-30 13F MAYVILLE ENGR COM 578605107 15,810 6,361 67.32 298 56.84 0.0000
2021-08-23 2021-06-30 13F/A-1 MAYVILLE ENGR COM 578605107 9,449 -4,228 -30.91 190 -3.55 0.0000
2021-08-16 2021-06-30 13F MAYVILLE ENGR COM 578605107 9,449 -4,228 190 0.0000
2021-05-17 2021-03-31 13F MAYVILLE ENGINEERING COM 578605107 13,677 -6,970 -33.76 197 -28.88 0.0000
2021-02-16 2020-12-31 13F MAYVILLE ENGINEERING COM 578605107 20,647 7,921 62.24 277 134.75 0.0000
2020-11-13 2020-09-30 13F MAYVILLE ENGINEERING COM 578605107 12,726 -1,655 -11.51 118 3.51 0.0000
2020-08-14 2020-06-30 13F MAYVILLE ENGINEERING COM 578605107 14,381 4,054 39.26 114 78.13 0.0000
2020-05-26 2020-03-31 13F/A-1 MAYVILLE ENGINEERING COM 578605107 10,327 -20,478 -66.48 64 -77.78 0.0000
2020-05-15 2020-03-31 13F MAYVILLE ENGINEERING COM 578605107 10,327 -20,478 64 4.9165
2020-02-14 2019-12-31 13F MAYVILLE ENGINEERING COM 578605107 30,805 -48,932 -61.37 288 -72.60 0.0001
2019-11-14 2019-09-30 13F MAYVILLE ENGINEERING COM 578605107 79,737 19,336 32.01 1,051 26.02 0.0003
2019-08-14 2019-06-30 13F MAYVILLE ENGINEERING COM 578605107 60,401 60,401 834 0.0002
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.