The Bombay Stock Exchange benchmark Sensex on Wednesday,surged by nearly 340 points to close at a 10-month high as funds remained aggressive buyers on expectations of higher spending in the Budget to boost economic growth. The 30-share index,gained 339.81 points,or 2.25 per cent,to settle at 15,466.81 points,a level last seen around mid-August 2008. It touched the day's high of 15,580.81 points. The wide-based National Stock Exchange index Nifty soared by 104.30 points,or 2.29 per cent,to 4,655.25,after touching the day's high of 4,688.95. Marketmen said that expectations of high spending in the Budget to boost economic growth and the firming global stock markets remained a positive factor for the market. Stocks in power,capital goods,consumer durables and banking segment were the major supporter to the rally. Metal shares spurted after the base-metal prices firmed up in global metal markets last night.