Why is my Buy/Sell order not done when it exceeds the day Low/High price?

Our system participates in the trading of NYSE/NYSE-MKT/NASDAQ listed stocks during exchange trading hours. We do not participate in the US pre-open and pre-close trading sessions. The US price feed reflected in our POEMS System may include trades done during off-market trading as well as trades from other US exchanges. As such, the opening, high, low and last done prices for US stocks in our system may include trades that are not executed on NYSE/ NYSE-MKT/ NASDAQ.