The Sensex at the Bombay Stock Exchange continues to trade in red after falling by 112 points in the afternoon trade as funds and retail investors preferred to book profits after two sessions of gains.The 30-Share barometer which dropped by 82 points in its previous session, fell by 112 points to trade at 18,680 when reports last came in. Similarly, the wide-based National Stock Exchange index Nifty shed 37 points to 5,681 a short while ago.