Benchmark indices opened with a gap-up on Wednesday and initially extended their gains, but the momentum failed to sustain, with selling pressure emerging as the session progressed. The indices subsequently traded lower through the day, giving up their early gains and closing in negative territory amid higher crude prices as Brent crude moved above $110. On the higher side, analysts say key level to watch is Monday's high of 23,175, only a move above the same will signal pullback towards 23,300 and 23,500 levels in the coming sessions being the 50% retracement of the entire recent decline from 24,774 to 22,180.