The Sensex opened with a positive gap of 69 points at 15,768, and soon spurted to a high of 15,812.

Profit-taking at higher levels saw the index slip into red to a low of 15,654 - down 158 points from the previous close.

Heavy short-covering, on account of July derivatives expiry, towards the end of the day saw the index rebound into the postive zone and shoot up over 100 points before settling with a gain of 77 points at 15,776.

The NSE Nifty ended up 31 points at 4620.