> If I'm not mistaken (and I might be, it's been awhile since I looked), Interactive Brokers were flashing their clients orders up until recently as well; they

> If I'm not mistaken (and I might be, it's been awhile since I looked), Interactive Brokers were flashing their clients orders up until recently as well; they didn't call it flashing, they called it "smart routing" -- but if you opted out, you paid routing fees whereas if you opted in, those fees would often be waived. IB has two types of routing, SMART routing and direct routing. SMART routing allows IB to seek the best price possible in the various liquidity sources it knows about. Direct routing sends your order directly to an exchange, where it may be matched, booked, or routed according to NMS rules. This has 0 to do with flash orders.