Maximize execution quality, minimize market impact


IBKR BestXTM is a powerful suite of advanced trading technologies designed to help clients achieve best execution and maximize price improvement while minimizing market impact and maintaining complete control over their orders.

Orders are routed by IBKR directly to one or more execution venues, including multiple exchanges, dark pools, and IBKR’s own alternative trading system (ATS).

IBKR BestX's suite of choices offers clients a powerful solution for helping to achieve best execution and price improvement across their trading activities by combining (depending on the product being traded) the IBUSOPT destination, the IBKR ATS, advanced order types, and IB SmartRoutingSM.


    For US listed equity options and certain index options, the IBUSOPT destination is designed to offer clients the opportunity to interact with IB SmartRouted marketable order flow and have their orders filled in between the National Best Bid/Offer (NBBO). Clients can buy between the bid and the midpoint or sell between the offer and the midpoint without revealing their trading interests to the market or being subject to adverse selection by market-moving orders (as they would be if their order were displayed on an exchange).


    For US listed stocks and ETFs, the IBKR ATS allows clients to choose to interact solely with IB SmartRouted order flow and access order flows that may not be available at exchanges. This helps to provide price improvement (by resting passive orders rather than crossing the spread) on large volume and block orders while minimizing market impact.

  • IB SmartRoutingSM

    IB SmartRoutingSM helps support best execution by continuously searching for the best available prices for stocks, options, and combinations across exchanges and dark pools. This technology dynamically re-routes all or part of clients' orders to achieve immediate electronic execution, while factoring in transaction costs, fees, rebates, and other factors that impact trade execution.

  • Advanced Order Types

    Both IBUSOPT and IBKR ATS offer Pegged-to-Midpoint and Pegged-to-Best order types, and the IBKR ATS also offers a Reroute to SMART order type.

    • The Pegged-to-Midpoint order type allows clients to peg their order to the midpoint of the bid-ask spread, meaning that if the order is executed, it will be done at the midpoint of the NBBO (the highest bid and the lowest ask). This order type helps traders get better prices by not having to pay the bid/ask spread.
    • The Pegged-to-Best order type allows clients to peg their order and compete by one tick with the best bid or ask price available in the market. Traders who use this order type want to ensure that their order is executed at better prices than are available on exchanges, regardless of the market conditions.
    • The Reroute to SMART order type allows clients to rest orders on IBKR ATS, and if they remain unfilled after a specified number of minutes, to automatically re-route the order using IB SmartRouting.
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