Our discussion of trailing stops earlier in the week brought this response from one of our subscribers about using trailing stops on ECN’s.

A trailing stop loss is very much something that can be done electronically and have been for over a year now. The ARCA ECN supports trailing stops on New York and Nasdaq both (REDI ECN will shortly). ARCA also supports GTC, Day and Day +, Now and BBO, Discretionary, MID, Stop-Market, Stop Limit, Bid and offer orders all on Nasdaq and well as NYSE for up to 90 days for the same order. The orders are stored on ARCA’s servers until the triggers hit and then execute. Set the order to your own desired prices and logout of your account if you like and the orders are still in play (most brokers today support ARCA). Options are the same way up to 20 contracts per order on the RAES networks. The orders never go to the brokers’ desk or to the exchange floor for trading. The order is matched up electronically. For orders over 20 contracts they are printed to a local printer on the trading floor for the floor trader to work. Since the ISE options exchange has open I can’t remember the last time my option order wasn’t filled immediately and at the bid or offer price.