Mumbai, May 7 -- The key equity benchmarks erased all their early gains and traded with marginal losses during Thursday's mid-morning session, as profit booking in heavyweight stocks and volatility ahead of the weekly Sensex derivatives expiry weighed on investor sentiment. The Nifty slipped below the 24,350 mark, while consumer durables stocks declined after advancing in the previous trading session.

At 11:30 IST, the barometer index, the S&P BSE Sensex lost 223.29 points or 0.29% to 77,735.13. The Nifty 50 index fell 25.60 points or 0.10% to 24,306.40.

The broader market outperformed the frontline indices. the BSE 150 MidCap Index advanced 0.40% and the BSE 250 SmallCap Index rallied 0.75%.

The market breadth was strong. On the BSE, ...