Reading the article below you get the impression, that you would always be better off sending your order to IEX.
However, when using Interactive Brokers' SMART routing, my orders rarely get executed at IEX.
Anyone has an idea why Interactive Brokers SMART routing rarely send orders to IEX?
IEX is great at PR but not some magic exchange where everyone gets filled for free and with price improvement. Often other exchanges are better outright, or other's are better factoring in fees/rebates, or better fills on dark pools, or any number of things. Smaller orders will often benefit from the HFT's providing liquidity, which is what IEX is trying to make more difficult.