MLM
Martin Marietta Materials
3 super-investors hold MLM worth a combined $454M. The largest position: Thomas Russo at 5.0% of their portfolio. No cohort buying or selling was filed on the name this quarter. Cohort Conviction Score: 31 — ranked #350 of 724 scored stocks.
Why super-investors own MLM
Thomas Russo dominates cohort exposure here, holding MLM at 5.0% of his portfolio — a $421M position that accounts for roughly 93% of the $454M combined cohort stake. Wallace Weitz and Joel Greenblatt round out the three owners, but at 1.6% and a negligible slice respectively, neither represents meaningful conviction. Activity in 2026Q1 was flat across the board — no additions, trims, or exits — and the owner count of three has been stable for several quarters after briefly dipping to two. Interest is neither rising nor fading; this is essentially a Russo-driven holding with two minor satellites, and the cohort as a whole appears content to hold rather than build.
AI-synthesized from 13F filings. Not investment advice.
Cohort owners over time
2016Q2 → 2026Q1How many of the cohort members held this stock each quarter.
Owners (3) · click any column to sort
| #↑ | Manager | % Port. | History | Value | Shares |
|---|---|---|---|---|---|
| 1 | Thomas Russo | 5.0% | 40q | $421M | 715,411 |
| 2 | Wallace Weitz | 1.6% | 35q | $23M | 39,775 |
| 3 | Joel Greenblatt | <0.1% | 40q | $10M | 16,730 |
Owners of MLM also hold
Long US equity 13F-HR filings only. CUSIP 573284106. Not investment advice.