MLM

Martin Marietta Materials

3 superinvestors own MLM

Based on latest 13F filings — data is 45–90 days delayed

Investor	Fund	Weight	Shares	Value	Quarter	Activity
Thomas Russo	Gardner Russo & Quinn	4.88%	726,612	$452.4M	2025Q4	New
Wallace Weitz	Weitz Investment Management	1.52%	41,275	$25.7M	2025Q4	New
Kenneth Fisher	Fisher Asset Management	0.00%	328	$205K	2025Q4	Reduced

Open-market purchases (P) and sales (S) from SEC Form 4 filings · last 12 months

No open-market insider trades in the last 12 months.

Form 4 filings for option exercises and other transaction types are excluded.

STOCK Act disclosures · last 12 months

Congressional trade data coming soon.

We are sourcing STOCK Act disclosures and will display them here shortly.

What Is SEC Form 4?

Understand the insider trade filings behind MLM activity.

What Is a 13F Filing?

How superinvestors disclose their quarterly holdings.

Insider Cluster Buying

Why multiple insiders buying together is a strong signal.

Superinvestor Consensus

The most widely held stocks across all tracked institutions.