South African bank Investec expects first half net operating income to be marginally down.As a result, operating profits will be lower than those reported in the first half of last year but better than the second half. Defaults have continued to increase in line with expectations, with the annualised credit loss ratio on core loans and advances expected to be between 0.95% and 1.1% for the six months ended 30 September 2009.UK and European operating profits are ahead of the prior year whereas the South African and Australian operations are expected to post a weaker performance.Since March core loans and advances grew by 3% to £16.7bn, customer deposits increased by 16% to £16.9bn and third party assets under management increased by 19% to £57.9bn. Net interest income has been negatively impacted by lower average interest rates over the period. Lower levels of activity over the period have resulted in a decline in net fees and commissions receivable.