MARKETAXESS HOLDINGS INC (MKTX) Stock Institutional Trading Activity


MARKETAXESS HOLDINGS INC (MKTX) 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 Renaissance Technologies LLC, Sequoia Financial Advisors, Polen Capital Management, Meritage Group, and Parnassus Endeavor Fund. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q1 2022Renaissance Technologies LLCSell-65,81025,973$8,836
Q4 2021Renaissance Technologies LLCSell-93,69091,783$37,748
Q4 2021Parnassus Endeavor FundBuy9,08877,751$31,977
Q3 2021Renaissance Technologies LLCSell-118,670185,473$78,027
Q3 2021Parnassus Endeavor FundBuy19,19368,663$28,886
Q2 2021Renaissance Technologies LLCSell-148,910304,143$140,998
Q2 2021Parnassus Endeavor FundBuy9,73149,470$22,934
Q1 2021Durable Capital PartnersBuy46,68346,683$23,244
Q1 2021Renaissance Technologies LLCSell-261,900453,053$225,584
Q1 2021ARK InvestBuy16,34933,195$16,528
Q4 2020Renaissance Technologies LLCSell-251,711714,953$407,924
Q4 2020ARK InvestBuy16,84616,846$9,612
Q3 2020Renaissance Technologies LLCSell-68,900966,664$465,536
Q3 2020Parnassus Endeavor FundBuy2,42839,739$19,138
Q2 2020Renaissance Technologies LLCSell-165,8001,035,564$518,735
Q2 2020Parnassus Endeavor FundBuy37,31137,311$18,690
Q1 2020Renaissance Technologies LLCBuy245,4101,201,364$399,538
Q4 2019Renaissance Technologies LLCBuy237,744955,954$362,412
Q3 2019Renaissance Technologies LLCBuy224,210718,210$235,214
Q2 2019Renaissance Technologies LLCBuy2,800494,000$158,781
Q1 2019Renaissance Technologies LLCBuy118,300491,200$120,874
Q4 2018Renaissance Technologies LLCBuy50,890372,900$78,797
Q3 2018Renaissance Technologies LLCBuy20,410322,010$57,476
Q2 2018Polen Capital ManagementSell-5711,281$253
Q1 2018Polen Capital ManagementBuy5521,852$403
Q1 2018Renaissance Technologies LLCBuy19,690301,600$65,580
Q4 2017Polen Capital ManagementBuy1,3001,300$262
Q4 2017Renaissance Technologies LLCSell-90,900281,910$56,875
Q3 2017Renaissance Technologies LLCBuy91,372372,810$68,787
Q2 2017Renaissance Technologies LLCBuy102,328281,438$56,597

Frequently asked questions about MKTX activity

  • Which institutional owners are buying MKTX?

    Institutional owners buying MKTX 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 MKTX activity?

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

  • Is institutional interest in MKTX increasing?

    Institutional interest in MKTX 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.