Asset manager Investec posted a 1% rise in first-quarter operating income as bad debt losses dropped 17%. Operating profit before goodwill, acquired intangibles, non-operating items and taxation and after total non-controlling interests is 10% ahead of the previous year, according to a trading update on Thursday.The South African-based company said its wealth and investment division reported strong growth in operating profit while its asset management arm achieved an increase marginally ahead of the year before.However, results were hurt by the depreciation of the South African rand against the pound which weakened about 22% over the period. In April the group announced that it had entered into an agreement with Bank of Queensland to sell Investec Bank Australia Limited's professional finance business, asset finance and leasing businesses and its deposit book. The sale was completed on Thursday.RD