Whale Analyzer
MCO Institutional Holders and 13F Ownership
Compare 9 tracked holders of MCO, their reported positions and disclosed changes. Coverage is limited to the investors tracked by Whale Analyzer; these records do not establish all shareholders or current trades. Warren Buffett is the largest reported holder at $11.17B; the top five funds control 97.5% of reported ownership; institutions were net selling last quarter (1 increased, 3 reduced); the stock trades above the aggregate whale cost basis of $175.3. Top tracked holders include Warren Buffett, Chris Hohn, Dev Kantesaria, and Chuck Akre.
Continue to the live MCO dashboardTop holders
| Investor | Reported value | Shares | Change | Report date |
|---|---|---|---|---|
| Warren Buffett 13F portfolio Berkshire Hathaway holdings | $11.17B | 24.7M | Held | 2026-06-30 |
| Chris Hohn 13F portfolio TCI Fund Management holdings | $6.49B | 14.3M | Held | 2026-06-30 |
| Dev Kantesaria 13F portfolio Valley Forge Capital Management holdings | $596.6M | 1.3M | Held | 2026-06-30 |
| Chuck Akre 13F portfolio Akre Capital Management holdings | $524.0M | 1.2M | Reduced | 2026-06-30 |
| Baillie Gifford 13F portfolio Baillie Gifford & Co holdings | $325.1M | 717.9K | Reduced | 2026-06-30 |
| Al Gore / David Blood 13F portfolio Generation Investment Management holdings | $243.9M | 538.5K | Increased | 2026-06-30 |
| Altarock Partners 13F portfolio Altarock Partners holdings | $137.1M | 302.6K | Reduced | 2026-06-30 |
| Tom Gayner 13F portfolio Markel Group holdings | $96.9M | 213.9K | Held | 2026-06-30 |
| Guy Spier 13F portfolio Aquamarine Fund holdings | $12.2M | 27.0K | Held | 2026-06-30 |
Ownership concentration
Reported ownership of MCO is highly concentrated across tracked institutions.
- Single largest holder: 57.0% of reported ownership
- Top 5 holders: 97.5%
- Top 10 holders: 100.0%
Whale activity this quarter
Across 9 tracked institutions, 5 held, 3 reduced, 1 increased. Net positioning is net selling.
- Warren Buffett — Berkshire Hathaway ($11.17B) (→ 0.0% qoq shares) · avg cost $131.63
- Chris Hohn — TCI Fund Management ($6.49B) (→ 0.0% qoq shares) · avg cost $238.43
- Dev Kantesaria — Valley Forge Capital Management ($596.6M) (→ 0.0% qoq shares) · avg cost $214.86
- Chuck Akre — Akre Capital Management ($524.0M) (▼ 7.2% qoq shares)
- Baillie Gifford — Baillie Gifford & Co ($325.1M) (▼ 6.1% qoq shares)
- Al Gore / David Blood — Generation Investment Management ($243.9M) (▲ 47.0% qoq shares) · avg cost $435.98
- Altarock Partners — Altarock Partners ($137.1M) (▼ 64.9% qoq shares)
- Tom Gayner — Markel Group ($96.9M) (→ 0.0% qoq shares) · avg cost $72.16
Whale cost basis vs current price
The aggregate tracked cost basis is $175.30 versus a current price of $474.95, so MCO trades above its cost basis (+170.9%). Average unrealized P&L across tracked holders: 187%.
Sector positioning — Other
MCO sits within the Other sector alongside 689 other tracked names. Compare whale ownership across peers:
How to use this page
Values are reported public positions from tracked 13F filers and disclosures — not real-time ownership totals. Open the live MCO dashboard for price charts and cross-investor scans, or read the SEC 13F guide.
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Learn more in Whale Analyzer Academy
Deepen your read on MCO with these Whale Analyzer Academy guides:
Frequently asked questions
Who owns MCO stock?
Whale Analyzer tracks 9 public institutional holders of MCO with a combined reported value of $19.60B. See the holder table above for the largest tracked positions.
Which top funds are buying MCO?
Tracked institutions were net selling last quarter — 5 held, 3 reduced, 1 increased. Check the "Change" column: "New" = fresh position, "Increased" = added, "Reduced" = trimmed.
How concentrated is MCO ownership?
The top five tracked holders report 97.5% of aggregate ownership.
Is MCO above or below the whale cost basis?
The aggregate tracked cost basis is $175.30 versus a current price of $474.95 (+170.9%).
What does 13F ownership mean for MCO?
These are historical reported positions from tracked filers, not real-time ownership or a complete shareholder register. Use the interactive MCO dashboard to explore them, or read our 13F Alpha Signals Guide.