Benchmark equity indices settled with gains on Thursday in a highly volatile session amid the scheduled monthly expiry of derivative contracts. The BSE Sensex rebounded 195.42 points or 0.27 per cent to settle at 72,500.30. The NSE Nifty50 gained 31.65 points or 0.14 per cent to close at 21,982.80. Sector-wise it was a mixed bag with buying seen in Banking, Financials, and Metals.