Boston Partners MEC — MAYVILLE ENGR CO INC

Ownership history in Boston Partners  ·  4 quarters on record

AI Ownership Summary

Boston Partners reported MAYVILLE ENGR CO INC (MEC) in 4 quarterly 13F filings from 2025 Q3 through 2026 Q2. Peak portfolio weight reached 0.02% in 2026 Q2. The latest visible filing shows MEC at 0.02% of the fund.

This page tracks quarterly shares, estimated market value, portfolio weight, filing dates, and disclosure-aligned stock prices directly from SEC EDGAR 13F filings.

What this MEC ownership page tells you

This page is designed to answer the real investor question behind a 13F filing: how meaningful was Boston Partners's position in MAYVILLE ENGR CO INC, and how did that conviction change over time? You can read the holding window, peak weight, latest reported size, disclosure timing, and quarter-by-quarter changes without piecing the story together from raw SEC rows.

Freshest filing
Latest Reported Filing
2026 Q2

MEC was reported at 0.02% of portfolio in the most recent visible filing.

High-water mark
Peak Conviction
0.02% in 2026 Q2

Peak weight helps separate a token disclosure from a real conviction holding the fund genuinely cared about.

Time in book
Holding Window
2025 Q3 to 2026 Q2

Longer holding windows often tell a very different story from short-lived tactical trades or one-quarter experiments.

Decision context
Why It Matters
Position size beats headlines

Knowing that a fund owned a stock is useful. Knowing whether it was a 0.20% placeholder or a true high-conviction position is where the signal actually starts.

MEC stock page Boston Partners fund profile Boston Partners full holdings
How Boston Partners held MEC — position size vs. price
% of Fund (quarterly)    MEC price (quarter-end, indexed to 100)    SPY (indexed to 100)    QQQ (indexed to 100)
📋 Quarterly Holdings History 4 quarters  ▾
Quarter Action Sold % After 3M Timing Shares Change Chg % % of Fund Mkt Value Filed Price (Filed)
2026 Q2 ADDED — — — 696,429 +463,792 +199.4% 0.02% $25.8M 2026-08-04 $27.73
2026 Q1 ADDED — — — 232,637 +9,907 +4.4% 0.00% $4.2M 2026-05-11 $27.26
2025 Q4 ADDED — — — 222,730 +24,570 +12.4% 0.00% $4.2M 2026-02-13 $21.94
2025 Q3 INITIATED — — — 198,160 — — 0.00% $2.7M 2025-11-13 $16.21

🏢 Other funds also holding MEC

As of 2026 Q2 — sorted by position size

SummerHaven Investment Management, LLC 3Y 0.91% Essential Investment Partners LLC 0.6% GatePass Capital, LLC 0.57% HUNTER ASSOCIATES INVESTMENT MANAGEMENT LLC 3Y 7Y 0.46% DELTA CAPITAL MANAGEMENT LLC 3Y 7Y 0.17% SHEETS SMITH WEALTH MANAGEMENT 3Y 7Y 0.14% ANCHOR CAPITAL ADVISORS LLC 3Y 7Y 0.09% HARBOR CAPITAL ADVISORS, INC. 3Y 0.07% North Star Investment Management Corp. 3Y 7Y 0.06% Persistent Asset Partners Ltd 0.02%

FAQ About Boston Partners and MEC

These are the practical questions this page is built to answer before you even open the full history table.

How long has Boston Partners reported owning MEC?

Boston Partners reported MEC across 4 quarterly 13F filings, from 2025 Q3 through 2026 Q2.

What was the largest reported MEC position in Boston Partners's portfolio?

The largest reported portfolio weight for MEC was 0.02% in 2026 Q2.

What is the latest reported MEC position on this page?

The most recent filing on this page is 2026 Q2, when Boston Partners reported 696,429 shares, equal to 0.02% of portfolio, with an estimated market value of $25.8M.

What does the chart on this MEC ownership page compare?

The chart compares Boston Partners's quarterly MEC portfolio weight with the stock's indexed share price, so you can see whether the fund was building, trimming, or holding the position as price moved.

How well did Boston Partners time their MEC position?

Based on 13F filing dates vs. subsequent MEC price moves, Boston Partners correctly timed 3 out of 3 reported position changes (100%). The annualised alpha on MEC relative to SPY over the holding period was +71.7%.

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