Interactive Brokers has a data variable called "After Hour Change %." You can use it for a specified list of tickers or as a column in market scanner. After hours trading starts at 16:00. However, the "After Hour Change %" does not appear until 16:15. Today the data did not appear for NYSE stocks before 16:15 and for Nasdaq stocks before 16:30. Can anyone explain why it does not appear and is not updated continuously from 16:00? I realize of course that the last price is updated continuously with the most recent price traded - also after hours. What I would like to know is why the "After Hours Change %" is not updated until 16:15 or 16:30. Thank you. Best regards, Maverick