The BSE benchmark Sensex gained over 26 points to 18,657.65 in early trade today after yesterday's losses on emergence of buying by funds and retailers. The 30-share barometer had lost 162 points in the previous session. Stocks of realty, oil and gas, and metal led the recovery.Similarly, the wide-based National Stock Exchange index Nifty was up 10 points at 5,662 .