MARTIN MARIETTA MATERIALS (MLM) Institutional Ownership and Insiders Activity

MARTIN MARIETTA MATERIALS (MLM) is widely held by institutional investors, with 4 tracked firms reporting positions valued at approximately $433.23M based on SEC Form 13F filings for the quarter ended June 30, 2026.

Gardner Russo & Quinn is the largest disclosed holder, reporting approximately $421.15M in MLM holdings in its latest filing.

Institutional ownership among tracked investors remains highly concentrated, with Gardner Russo & Quinn representing the majority of disclosed value.

Recent insider activity includes 4 tracked Form 4 transactions over the last three months, reflecting ongoing executive and director trading activity.