The London-based bank with operations in Asia, Africa and the Middle East on Thursday reported credit impairments of $611m in the second quarter, up from $176m a year ago and in addition to $956m reported in the first quarter.

Net profit fell 30% to $339m in the quarter, compared with $482m a year earlier. Pre-tax profit fell to $1.63bn in the six months to June 30 from $2.41bn last year, but was higher than the company's own compiled forecast of $1.53bn.

StanChart said it expected second half bad debt provisions to be lower unless economic conditions deteriorate significantly, adding that income in the same period would fall as financial market trading activity slowed on the back of weaker interest rates.

"Low interest rates and depressed oil prices continue to be headwinds and we expect new waves of COVID-19 related challenge in the coming quarters," said chief executive Bill Winters.

Profits at the retail, commercial and private banking business almost halved, while the corporate and institutional banking unit fell 13% in volatile markets as companies looked for equity and bond market raisings to bolster their balance sheets.

StanChart and rival HSBC Holdings drew sharp criticism last month when they sided with China over its imposition of a controversial national security law in Hong Kong.

The banks were accused of enabling Beijing to undermine the rule of law in the former British colony after they claimed the draconian legislation would restore stability in the territory.

StanChart's chairman José Viñals said the bank was "convinced that more collaboration - not less - is the best way to find a sustainable equilibrium in these complex situations, but we do not expect an easy or quick resolutionW.

"We do believe, however, that Hong Kong will continue to play a key role as an international financial hub and we are fully committed to contributing to its continued success," he added.