what is an unlinked market and the risk during extended trading 
extended hours trading systems are not linked and the price of a stock displayed on one trading system may not reflect the price of the same stock displayed on another trading system 1the bottom lineextended trading on the exchanges occurs on electronic marketplaces outside of the official trading hours stock exchanges in the u s trade from 9 30 a m to 4 00 p m est and extended trading occurs outside these hours risks for investors who trade during extended hours include price volatility and larger quote spreads most brokers require traders to enter limit orders during extended trading sessions 