How are stock prices determined in an Electronic Crossing Network. The answer for one of the question states that the size of the order has no impact on the price in an ECN because it’s an existing price determined somewhere else. Does that make sense? I thought any trade order is always part of the supply demand equation. Any comments?

ECN = Electronic Communication Network The price is Avg (bid, ask), therefore, no impact on market.

They just reference the price on an exchange at that point in time.

the purpose of the electronic crossing network is anonymity (I am sure you know this already, but just in case)… large orders don’t have any impact on the price and there is no information leakage… Folks sitting in ECN offices get the bid-ask prices from other markets (order-driven or else) and try their best to match the buyers and the sellers to fulfill the orders…

plus they are used by the institutions (for large order). they don’t give spread to dealers.

Does anyone know if an ECN is the same as what MiFID in Europe calls a sytematic internaliser?

I think you are talking about Electronic “Crossing” Networks, rathet than Electronic “Communication” Networks. What is difference between Electronic “Crossing” Networks & Electronic “Communication” Networks ? Equipment & function are different ?

ECN is meant to describe Electronic communication network. the average of bid and ask and no price discovery is for electronic crossing network (not ECN)