An order (buy or sell order) that is placed in the market or a venue in advance of the public quote stream. This involves a very short display (up to 500 milliseconds and often as often as low as 30 milliseconds) of an order that is better than the national best bid or offer (NBBO) to solicit traders’ responses.

Pre-routing orders have been terminated by many exchanges, mainly due to the fact that the structure creates a two-tier market that can favor certain investors and disfavor others, leading to a compromised market fairness.

Pre-routing orders are also known as flash orders.