In September, the market turnover including F&O and cash at BSE and NSE touched lifetime high of R8.52 lakh crore. The daily average market turnover in last five months had been in excess of R3 lakh crore. Experts say the surge in markets in last half-an-hour suggests short-covering by traders. On the last day of expiry, generally, the quantum of longs and shorts that has not rolled over in the F&O segment, determine the quantum of fall or rise on the index for the day. However, the market surge came as a positive surprise. The way markets shot up in the last hour suggests, traders were caught off the guard on the short side, said Manish Sonthalia, head (equity PMS), Motilal Oswal AMC.