Deutsche Bank posted a surprise net profit in the first quarter that was helped by lower litigation costs, but Chief Executive John Cryan warned investors not to expect good results for the full year. Quarterly net income fell 58 per cent to Euro 236 million ($267.5 million) after its investment bank slumped in volatile markets and following its exit from certain businesses, but beat analysts' average expectation for a net loss of Euro 249 million. Shares in Germany's flagship lender, which announced a restructuring plan last October, were 3.6 per cent higher on Thursday in a market that was down by 1.3 per cent.