# MERCK & CO INC (MRK) — Institutional Ownership

Source: SEC EDGAR 13F filings, congressional STOCK Act disclosures, SEC Form 4 insider transactions.
CUSIP: 58933Y105
Page URL: https://superinvestorclub.com/stock/MRK
Last updated: 2026-07-08T11:37:39.930Z

## Summary

As of the most recent 13F filing period, MERCK & CO INC (MRK) is held by 11 tracked superinvestors with an aggregate position value of $196.5M representing 085421222728817290013605013301350348446338850251121411671 shares.

## Top institutional holders (11)

| Rank | Manager | Fund | Shares | Value | % of Portfolio | Period |
|------|---------|------|--------|-------|----------------|--------|
| 1 | [Sarah Ketterer](https://superinvestorclub.com/manager/293) | Causeway Capital Management | 854212 | $102.8M | 1.26% | 2026-03-31 |
| 2 | [Kahn Brothers](https://superinvestorclub.com/manager/83) | Kahn Brothers Group | 227288 | $27.3M | 4.85% | 2026-03-31 |
| 3 | [Prem Watsa](https://superinvestorclub.com/manager/71) | Fairfax Financial Holdings | 172900 | $20.8M | 1.07% | 2026-03-31 |
| 4 | [Dodge & Cox](https://superinvestorclub.com/manager/16) | Dodge & Cox | 136050 | $16.4M | 0.01% | 2026-03-31 |
| 5 | [FPA Queens Road](https://superinvestorclub.com/manager/97) | Bragg Financial Advisors | 133013 | $16.0M | 0.51% | 2026-03-31 |
| 6 | [Mairs & Power](https://superinvestorclub.com/manager/92) | Mairs & Power | 50348 | $6.1M | 0.06% | 2026-03-31 |
| 7 | [Christopher Bloomstran](https://superinvestorclub.com/manager/32) | Semper Augustus Investments | 44633 | $5.4M | 0.64% | 2026-03-31 |
| 8 | [Dan Sundheim](https://superinvestorclub.com/manager/3261) | D1 Capital Partners | 8850 | $1.1M | 0.45% | 2026-03-31 |
| 9 | [Richard Pzena](https://superinvestorclub.com/manager/288) | Pzena Investment Management | 2511 | $302,048 | 0.00% | 2026-03-31 |
| 10 | [Tom Russo](https://superinvestorclub.com/manager/30) | Gardner Russo & Gardner | 2141 | $257,536 | 0.00% | 2026-03-31 |
| 11 | [David Katz](https://superinvestorclub.com/manager/79) | Matrix Asset Advisors | 1671 | $201,005 | 0.02% | 2026-03-31 |

## Ownership history (quarter-over-quarter)

- 2023-09-30: 3 holders, $66.5M aggregate, 063879338423256 shares
- 2023-12-31: 4 holders, $86.4M aggregate, 062454116094538063287 shares
- 2024-03-31: 8 holders, $499.0M aggregate, 020902566932926138151729001604954444335132862 shares
- 2024-06-30: 8 holders, $409.4M aggregate, 018019915919115308951729001588764444334462862 shares
- 2024-09-30: 8 holders, $336.0M aggregate, 01554270580488547423172900533874444330872862 shares
- 2024-12-31: 10 holders, $252.0M aggregate, 014394305089081729001573511404845390044443963629262862 shares
- 2025-03-31: 12 holders, $895.6M aggregate, 074693608978695348664922751729001570691417355315944443898829462763 shares
- 2025-06-30: 11 holders, $973.0M aggregate, 09131318115072298266049046517290015730014647544443879233242915 shares
- 2025-09-30: 12 holders, $1.05B aggregate, 0982360811340575139434337501729001542751476785218744443879733242870 shares
- 2025-12-31: 12 holders, $1.73B aggregate, 01408870510446174301033102211729001464561382055199944443882833242862 shares
- 2026-03-31: 11 holders, $196.5M aggregate, 085421222728817290013605013301350348446338850251121411671 shares

## Recent congressional trades (50)

- 2026-01-13: Michael McCaul (Republican-TX) sale $15,001 - $50,000
- 2025-12-19: Gil Cisneros (Democrat-CA) purchase $1,001 - $15,000
- 2025-12-18: Julie Johnson (Democrat-TX) sale $1,001 - $15,000
- 2025-11-18: Gil Cisneros (Democrat-CA) purchase $1,001 - $15,000
- 2025-11-13: Julie Johnson (Democrat-TX) sale $1,001 - $15,000
- 2025-10-27: Michael McCaul (Republican-TX) sale $15,001 - $50,000
- 2025-08-28: Marjorie Taylor Greene (Republican-GA) purchase $1,001 - $15,000
- 2025-08-22: Michael McCaul (Republican-TX) sale $50,001 - $100,000
- 2025-08-14: Julie Johnson (Democrat-TX) sale $1,001 - $15,000
- 2025-08-05: Gil Cisneros (Democrat-CA) purchase $1,001 - $15,000
- 2025-08-04: Lisa McClain (Republican-MI) sale $1,001 - $15,000
- 2025-08-04: Ro Khanna (Democrat-CA) purchase $1,001 - $15,000
- 2025-07-11: Ritchie Torres (Democrat-NY) sale $1,001 - $15,000
- 2025-07-01: Ro Khanna (Democrat-CA) purchase $1,001 - $15,000
- 2025-06-27: Michael McCaul (Republican-TX) sale $100,001 - $250,000

## Recent insider transactions (0)


## Citation

When citing, use: "MERCK & CO INC (MRK) institutional ownership data via Superinvestor (https://superinvestorclub.com/stock/MRK), aggregating SEC 13F, Form 4, and congressional disclosures."