Stock Ownership/MRK

MERCK CO INC (MRK): Ownership & Insider Activity

Hedge funds and institutional managers reporting a position in MRK · Health Care. Based on the most recent 13F filing from each holder, sourced from SEC EDGAR.

Reported Holders
42
13F filers
Aggregate Value
$11.3B
Across holders
Last Price
$150.66
2026-08-24
Sector
Health Care
GICS
Quarterly fund activity15 increased25 reduced2 exited
Full exits: Lighthouse Investment Partners, LLC, MARSHALL WACE, LLP
Institutional Holders of MRK
↗
42 holders
Manager⇅Type⇅Shares⇅Market Value▼% of Total⇅% of Portfolio⇅Action⇅QoQ Change⇅Quarter⇅
Fisher Asset Management, LLC
CIK 0000850529
Institutional Manager38.52M$4.9B43.8%1.5%Added+$1.6BQ2 2026
HARRIS ASSOCIATES L P
CIK 0000813917
Institutional Manager12.07M$1.6B13.7%2.1%Reduced+$1.4BQ2 2026
AQR CAPITAL MANAGEMENT LLC
CIK 0001167557
Hedge Fund8.13M$1.0B9.2%0.4%Reduced$-10.7BQ2 2026
Grantham, Mayo, Van Otterloo & Co. LLC
CIK 0001352662
Institutional Manager6.79M$871.9M7.7%2.0%Reduced$-29.4MQ2 2026
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP
CIK 0001164508
Hedge Fund3.97M$509.7M4.5%0.2%Added+$132.4MQ2 2026
SHAW D E & CO INC
CIK 0001009207
Hedge Fund2.74M$351.8M3.1%0.2%Reduced$-170.3MQ2 2026
ADAGE CAPITAL PARTNERS GP, L.L.C.
CIK 0001165408
Hedge Fund2.03M$260.9M2.3%0.4%Reduced$-84.5MQ2 2026
CITADEL ADVISORS LLC
CIK 0001423053
Hedge Fund1.93M$248.5M2.2%0.0%Reduced$-713.5MQ2 2026
Rockefeller Capital Management L.P.
CIK 0001739439
Hedge Fund1.85M$237.5M2.1%0.4%Added$-1.0BQ2 2026
Woodline Partners LP
CIK 0001784547
Hedge Fund1.12M$144.5M1.3%0.4%Added+$6.8MQ2 2026
Fisher Asset Management, LLCAdded
Institutional Manager
$4.9B· 43.8% of total· 1.5% port· 38.52M sh· +$1.6B QoQ· Q2 2026
HARRIS ASSOCIATES L PReduced
Institutional Manager
$1.6B· 13.7% of total· 2.1% port· 12.07M sh· +$1.4B QoQ· Q2 2026
AQR CAPITAL MANAGEMENT LLCReduced
Hedge Fund
$1.0B· 9.2% of total· 0.4% port· 8.13M sh· $-10.7B QoQ· Q2 2026
Grantham, Mayo, Van Otterloo & Co. LLCReduced
Institutional Manager
$871.9M· 7.7% of total· 2.0% port· 6.79M sh· $-29.4M QoQ· Q2 2026
ARROWSTREET CAPITAL, LIMITED PARTNERSHIPAdded
Hedge Fund
$509.7M· 4.5% of total· 0.2% port· 3.97M sh· +$132.4M QoQ· Q2 2026
SHAW D E & CO INCReduced
Hedge Fund
$351.8M· 3.1% of total· 0.2% port· 2.74M sh· $-170.3M QoQ· Q2 2026
ADAGE CAPITAL PARTNERS GP, L.L.C.Reduced
Hedge Fund
$260.9M· 2.3% of total· 0.4% port· 2.03M sh· $-84.5M QoQ· Q2 2026
CITADEL ADVISORS LLCReduced
Hedge Fund
$248.5M· 2.2% of total· 0.0% port· 1.93M sh· $-713.5M QoQ· Q2 2026
Rockefeller Capital Management L.P.Added
Hedge Fund
$237.5M· 2.1% of total· 0.4% port· 1.85M sh· $-1.0B QoQ· Q2 2026
Woodline Partners LPAdded
Hedge Fund
$144.5M· 1.3% of total· 0.4% port· 1.12M sh· +$6.8M QoQ· Q2 2026
Qube Research & Technologies LtdAdded
Hedge Fund
$134.2M· 1.2% of total· 0.1% port· 1.04M sh· +$77.9M QoQ· Q2 2026
Man Group plcAdded
Hedge Fund
$127.3M· 1.1% of total· 0.2% port· 990K sh· +$17.6M QoQ· Q2 2026
Squarepoint Ops LLCAdded
Hedge Fund
$116.9M· 1.0% of total· 0.1% port· 910K sh· +$54.5M QoQ· Q2 2026
TCW GROUP INCReduced
Hedge Fund
$108.7M· 1.0% of total· 0.7% port· 846K sh· $-42.3M QoQ· Q2 2026
ORBIMED ADVISORS LLCUnchanged
Hedge Fund
$85.2M· 0.8% of total· 1.6% port· 663K sh· +$0 QoQ· Q2 2026
Holocene Advisors, LPAdded
Hedge Fund
$80.7M· 0.7% of total· 0.2% port· 628K sh· +$7.1M QoQ· Q2 2026
Clearbridge Investments, LLCReduced
Hedge Fund
$72.7M· 0.6% of total· 0.1% port· 566K sh· $-1.6M QoQ· Q2 2026
MILLENNIUM MANAGEMENT LLCReduced
Hedge Fund
$72.1M· 0.6% of total· 0.0% port· 561K sh· $-181.1M QoQ· Q2 2026
Gotham Asset Management, LLCAdded
Hedge Fund
$68.0M· 0.6% of total· 0.2% port· 529K sh· +$2.9M QoQ· Q2 2026
FRED ALGER MANAGEMENT, LLCAdded
Hedge Fund
$63.0M· 0.6% of total· 0.2% port· 488K sh· +$21.5M QoQ· Q2 2026
Point72 Asset Management, L.P.Reduced
Hedge Fund
$48.8M· 0.4% of total· 0.1% port· 380K sh· +$40.0M QoQ· Q2 2026
PineBridge Investments, L.P.Reduced
Hedge Fund
$36.3M· 0.3% of total· 0.3% port· 433K sh· $-3.5M QoQ· Q3 2025
FARALLON CAPITAL MANAGEMENT LLCReduced
Hedge Fund
$25.6M· 0.2% of total· 0.1% port· 199K sh· $-20.8M QoQ· Q2 2026
DODGE & COXReduced
Institutional Manager
$17.4M· 0.2% of total· 0.0% port· 136K sh· $-39K QoQ· Q2 2026
Parallax Volatility Advisers, L.P.Reduced
Hedge Fund
$14.9M· 0.1% of total· 0.0% port· 116K sh· +$9.9M QoQ· Q2 2026
GAMCO INVESTORS, INC. ET ALReduced
Institutional Manager
$8.1M· 0.1% of total· 0.1% port· 63K sh· $-269K QoQ· Q2 2026
BALYASNY ASSET MANAGEMENT LLCReduced
Hedge Fund
$7.2M· 0.1% of total· 0.0% port· 56K sh· $-225.7M QoQ· Q2 2026
Verition Fund Management LLCAdded
Hedge Fund
$6.9M· 0.1% of total· 0.0% port· 54K sh· +$6.5M QoQ· Q2 2026
Brevan Howard Capital Management LPReduced
Hedge Fund
$6.4M· 0.1% of total· 0.0% port· 50K sh· +$3.0M QoQ· Q2 2026
TWO SIGMA INVESTMENTS, LPReduced
Hedge Fund
$6.2M· 0.1% of total· 0.0% port· 49K sh· $-858K QoQ· Q2 2026
Eisler Capital (UK) Ltd.Added
Hedge Fund
$5.0M· 0.0% of total· 0.0% port· 44K sh· $-78.4M QoQ· Q3 2024
PRIMECAP MANAGEMENT CO/CA/Reduced
Institutional Manager
$4.6M· 0.0% of total· 0.0% port· 36K sh· $-26K QoQ· Q2 2026
Bridgewater Associates, LPAdded
Hedge Fund
$3.9M· 0.0% of total· 0.0% port· 30K sh· — QoQ· Q2 2026
Bridgewater Advisors Inc.Added
Hedge Fund
$3.1M· 0.0% of total· 0.2% port· 24K sh· +$12K QoQ· Q2 2026
Ancora Advisors, LLCReduced
Hedge Fund
$2.7M· 0.0% of total· 0.1% port· 21K sh· +$1.2M QoQ· Q2 2026
Schonfeld Strategic Advisors LLCReduced
Hedge Fund
$2.0M· 0.0% of total· 0.0% port· 16K sh· $-2.5M QoQ· Q2 2026
Fulcrum Asset Management LLPReduced
Hedge Fund
$1.6M· 0.0% of total· 0.2% port· 12K sh· $-1.5M QoQ· Q2 2026
CAPSTONE INVESTMENT ADVISORS, LLCReduced
Hedge Fund
$515K· 0.0% of total· 0.0% port· 4K sh· $-50.5M QoQ· Q2 2026
JUPITER ASSET MANAGEMENT LTDAdded
Hedge Fund
$450K· 0.0% of total· 0.0% port· 4K sh· +$58K QoQ· Q2 2026
PZENA INVESTMENT MANAGEMENT LLCUnchanged
Institutional Manager
$323K· 0.0% of total· 0.0% port· 3K sh· +$0 QoQ· Q2 2026
Hudson Bay Capital Management LPReduced
Hedge Fund
$284K· 0.0% of total· 0.0% port· 2K sh· $-12.8M QoQ· Q2 2026
Walleye Capital LLCReduced
Hedge Fund
$274K· 0.0% of total· 0.0% port· 2K sh· $-9.5M QoQ· Q2 2026
1–10 of 42
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