AXCELIS TECHNOLOGIES INC (ACLS) Stock Institutional Trading Activity


AXCELIS TECHNOLOGIES INC (ACLS) 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, First Eagle U.S. Value, Sequoia Financial Advisors, and Donald Smith & Co.. 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 2019Renaissance Technologies LLCSell-16,400184,499$3,712
Q4 2018Renaissance Technologies LLCSell-28,800200,899$3,576
Q3 2018Renaissance Technologies LLCBuy68,400229,699$4,514
Q1 2018Renaissance Technologies LLCBuy98,600161,299$3,968
Q4 2017Renaissance Technologies LLCSell-40062,699$1,799
Q3 2017Donald Smith & Co.Sell-353,2272,282,471$62,426
Q2 2017Donald Smith & Co.Sell-360,9532,635,698$55,218
Q2 2017Renaissance Technologies LLCBuy43,14963,099$1,322
Q1 2017Donald Smith & Co.Buy192,1112,996,651$56,337
Q4 2016Renaissance Technologies LLCSell-100,39919,950$290
Q4 2016Donald Smith & Co.Sell-182,7652,804,540$40,806
Q3 2016Renaissance Technologies LLCBuy120,349120,349$1,598
Q3 2016Donald Smith & Co.Sell-8,365,3642,987,305$39,671
Q2 2016Donald Smith & Co.Buy11,352,66911,352,669$30,539

Frequently asked questions about ACLS activity

  • Which institutional owners are buying ACLS?

    Institutional owners buying ACLS 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 ACLS activity?

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

  • Is institutional interest in ACLS increasing?

    Institutional interest in ACLS 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.