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 2017Renaissance Technologies LLCSell-4,400179,110$33,581
Q4 2016Renaissance Technologies LLCBuy181,010183,510$26,961
Q2 2016Renaissance Technologies LLCSell-104,2002,500$363
Q1 2016Renaissance Technologies LLCSell-82,610106,700$13,319
Q4 2015Renaissance Technologies LLCSell-23,100189,310$21,125
Q3 2015Renaissance Technologies LLCBuy15,210212,410$19,729
Q2 2015Renaissance Technologies LLCBuy24,100197,200$18,294
Q1 2015Renaissance Technologies LLCSell-6,400173,100$14,350
Q4 2014Renaissance Technologies LLCSell-185,610179,500$12,872
Q3 2014Renaissance Technologies LLCSell-223,300365,110$22,586
Q2 2014Renaissance Technologies LLCBuy87,900588,410$31,809
Q1 2014Renaissance Technologies LLCBuy81,810500,510$29,640
Q4 2013Renaissance Technologies LLCBuy4,600418,700$28,023
Q3 2013Renaissance Technologies LLCSell-85,510414,100$24,827
Q2 2013Renaissance Technologies LLCBuy499,610499,610$23,357

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.