DBS Group Holdings reported a surprise drop in third-quarter profit as Southeast Asia’s largest bank boosted bad-loan allowances more than sixfold in an effort to deal with its problem lending to the regional oil and gas services sector.The bank reported a 23 percent drop in net income to S$822 million (602 million dollars), worse than even the most pessimistic of analyst forecasts, but indicated it now hopes to draw a line under the bad-debt issues by recognising more of its energy services