An alternative trading system (ATS) that electronically conducts a matching (crossing) process for buy and sell orders (involving publicly traded securities) for execution/ filling, without using a public market (a market that displays a public quote). In other words, the order will not be routed to an exchange (a public market/ displayed market such as an electronic communication network or ECN) in the first place.

Crossing networks allow traders to deal in large quantities of a specific security away from organized venues, so that market prices will not be impacted or distorted by large transactions.