Bank of America further boosted investor sentiment in the US banking sector on Monday, posting better-than-expected second-quarter results including a strong performance in investment banking.

The results came nine months after Ken Lewis, BofA chief executive, generated headlines by declaring he had endured “all the fun he could handle” in investment banking following big mortgage-related losses. After that comment, BofA pared back its proprietary trading activities and sold its prime brokerage business serving hedge funds.