MERCK & CO. INC. (MRK) Stock Institutional Trading Activity


MERCK & CO. INC. (MRK) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Causeway Capital Management, Cullen Value Fund, Kahn Brothers Group, Matrix Private Capital Group, and Mairs & Power Growth Fund. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

Explore more:

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q3 2021Matrix Advisors Value FundBuy2,148175,000$13,144
Q3 2021Renaissance Technologies LLCBuy740,2001,499,000$112,590
Q3 2021Gardner Russo & QuinnBuy103,878$291
Q2 2021Dodge & Cox Stock FundSell-18,058229,028$17,812
Q2 2021Sound Shore ManagementSell-11,7341,246,859$96,968
Q2 2021Parnassus Endeavor FundBuy1,707,3021,707,302$132,777
Q2 2021Matrix Private Capital GroupBuy2210,612$832
Q2 2021Mairs & Power Growth FundSell-8,92066,953$5,207
Q2 2021Sequoia Financial AdvisorsBuy16,93076,983$5,987
Q2 2021Hillman Value FundBuy27,57995,557$7,431
Q2 2021Matrix Advisors Value FundBuy30,974172,852$13,443
Q2 2021Renaissance Technologies LLCBuy251,366758,800$59,012
Q2 2021Berkshire HathawaySell-8,725,1969,157,192$712,155
Q2 2021Hancock Classic ValueSell-9277,619$593
Q2 2021Gardner Russo & QuinnBuy103,868$301
Q1 2021Dodge & Cox Stock FundSell-28,078247,086$19,048
Q1 2021Sound Shore ManagementSell-90,1531,258,593$97,025
Q1 2021Matrix Private Capital GroupBuy2,42810,590$823
Q1 2021Semper Augustus Investments GroupBuy2944,073$3,398
Q1 2021Sequoia Financial AdvisorsBuy13,37460,053$4,629
Q1 2021Hillman Value FundBuy9,09767,978$5,240
Q1 2021Mairs & Power Growth FundSell-5,89875,873$5,849
Q1 2021Matrix Advisors Value FundBuy20,941141,878$10,937
Q1 2021Renaissance Technologies LLCBuy479,219507,434$39,118
Q1 2021Berkshire HathawaySell-10,815,04717,882,388$1,378,553
Q1 2021Hancock Classic ValueSell-17,0528,546$659
Q1 2021Fairfax Financial HoldingsBuy50,000172,900$13,329
Q1 2021Gardner Russo & QuinnSell-863,858$297
Q4 2020Torray FundSell-1,00114,198$1,161
Q4 2020Dodge & Cox Stock FundSell-32,565275,164$22,508

Frequently asked questions about MRK activity

  • Which institutional owners are buying MRK?

    Institutional owners buying MRK include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in MRK activity?

    "Buy" means an investor increased their reported position in MRK compared to the prior reporting period. This reflects growing exposure to MERCK & CO. INC. (MRK) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in MRK increasing?

    Institutional interest in MRK can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.