I am using the API with delayed data and am getting a delayed last of 0. According to the documentation this is the last traded price, https://interactivebrokers.github.io/tws-api/tick_types.html Other fields such as the delayed ask, bid and volume are populated as expected. The delayed ask of 0 only happens for a few contracts I try, with one being: conid = 343699133 symbol = HG FUT NYMEX. gives, id=788 DelayedClose=3.087 noAutoExecute pastLimit=False preOpen=False id=788 DelayedLast=0 noAutoExecute pastLimit=False preOpen=False id=788 DelayedOpen=3.0945 noAutoExecute pastLimit=False preOpen=False id=788 DelayedBid=3.0455 noAutoExecute pastLimit=False preOpen=False id=788 DelayedAsk=3.047 noAutoExecute pastLimit=False preOpen=False What does this mean?