INTERACTIVE BROKERS GRO-CL A (IBKR) Institutional Ownership Changes & 13F Activity

INTERACTIVE BROKERS GRO-CL A (IBKR) institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC 13F filings (Q1 2026). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions among tracked filers. Notable filers include Cantillon Capital Management, Viking Global Investors, Egerton Capital UK, Ancient Art (Teton Capital), and Renaissance Technologies LLC.

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q3 2020Renaissance Technologies LLCBuy191,300429,000$20,734
Q3 2020ARK InvestBuy65,391166,857$8,064
Q3 2020Cantillon Capital ManagementSell-25,6362,488,447$120,266
Q3 2020Ancient Art (Teton Capital)Sell-1,6581,889,915$91,340
Q2 2020Bares Capital ManagementSell-368,8095,711,303$238,561
Q2 2020Ariel Appreciation FundBuy275,652275,652$11,514
Q2 2020Renaissance Technologies LLCSell-180,200237,700$9,929
Q2 2020ARK InvestBuy71,145101,466$4,238
Q2 2020Cantillon Capital ManagementBuy18,7932,514,083$105,013
Q1 2020Bares Capital ManagementSell-1,393,5036,080,112$262,478
Q1 2020Ancient Art (Teton Capital)Buy272,3001,891,573$81,659
Q1 2020ARK InvestBuy12,50030,321$1,309
Q1 2020Cantillon Capital ManagementSell-7,1482,495,290$107,721
Q1 2020Oakcliff Capital PartnersBuy4,331388,286$16,762
Q4 2019Cantillon Capital ManagementSell-52,7712,502,438$116,664
Q4 2019Oakcliff Capital PartnersBuy40,000383,955$17,900
Q4 2019Bares Capital ManagementBuy35,4017,473,615$348,420
Q4 2019ARK InvestSell-10,18917,821$831
Q3 2019Bares Capital ManagementBuy194,2907,438,214$400,027
Q3 2019Cantillon Capital ManagementSell-18,4062,555,209$137,419
Q3 2019ARK InvestBuy1,11628,010$1,506
Q2 2019Bares Capital ManagementBuy59,3557,243,924$392,621
Q2 2019Cantillon Capital ManagementSell-45,0232,573,615$139,490
Q2 2019ARK InvestBuy7,29026,894$1,458
Q1 2019Bares Capital ManagementBuy255,0987,184,569$372,735
Q1 2019Cantillon Capital ManagementSell-20,2822,618,638$135,855
Q1 2019ARK InvestBuy14,93019,604$1,017
Q1 2019Ancient Art (Teton Capital)Sell-5001,619,273$84,008
Q4 2018Bares Capital ManagementBuy1,071,2886,929,471$378,696
Q4 2018Ancient Art (Teton Capital)Buy150,4571,619,773$88,521

Frequently asked questions about IBKR activity

  • Which institutional owners are buying IBKR?

    Institutional owners buying IBKR 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 IBKR activity?

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

  • Is institutional interest in IBKR increasing?

    Institutional interest in IBKR 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.

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