A cross trade is when a broker crosses the two orders internally (i.e. a client was buying 10,000 calls for X and another client was selling 10,000 calls at the same price X) and then reports it to the exchange. So the point is that there is a time delay between the trade and the print on the tape, hence the trade price has no association with the market quotes at the time of the print.
MTE, thanks for your explanation. I dig a little bit in OPRA tick data specification. And I had a question for you. Say paper received two orders from same client and was asked to do cross trade in two accounts both belongs to that client. Paper didn't go to floor and there are no locals involved. There is a delay as you said to print those two trades on tape. Ok, my question is what will be showed on tape for that cross trade? What will be showed in tick data from live datafeed? Are those two things same?
A cross trade will show up in time&sales data with a condition code attached to it that it was a cross trade. I know on bloomberg you can see the condition codes, but I would imagine not all services show this.