Auto stocks,led by Mahindra & Mahindra,today slumped by up to 5.31 per cent on the Bombay Stock Exchange as investors preferred profit booking,amid a weak broader market. Shares of Mahindra & Mahindra (M&M) tumbled 5.31 per cent - the most among the 30 stocks of Sensex - to close at Rs 668.35 on the BSE. In intra-day session,the stock had plunged by 7.18 per cent to a month's low of Rs 655.15. "Auto stocks fell because the sector is reeling under pressure of rising prices of crude oil globally,along with increasing metal prices which have largely hurt investors sentiment back home and forced them to take away profits," a market expert said. Country's largest car maker Maruti Suzuki lost 2.92 per cent on the BSE. Other major shares that lost from the auto pack were Hero Honda and Tata Motors,which fell by 1.95 per cent and 0.57 per cent,respectively. However,bucking the weakness in the sector was Bajaj Auto,which emerged as the lone gainer among the frontline stocks by surging 1.27 per cent. Meanwhile,the BSE barometer index Sensex dropped 441.16 points to settle at 18,008.15.