HSBC said Wednesday it will spend up to $2.5 billion in the second half of the year to buy back shares after the successful sale of its Brazil unit in July.

Earnings dropped amid "considerable uncertainty" in the first half of the year, said chief executive Stuart Gulliver. The British bank said Wednesday its second-quarter net profit plunged 40% to $2.61 billion. Profit before tax dropped 45% to $3.61 billion in the quarter.