HSBC’s (HSBA.L) first quarter profits fell 20 percent from a year ago to $6.8 billion as revenue dipped at its investment bank, while last year’s earnings were swelled by asset sales. HSBC, which is Europe’s biggest bank but makes most of its profits in Asia, said it had continued to experience “muted customer activity” in April. Most investment banks have seen income drop in the first quarter after a grim start to the year for bond and interest rate trading, and HSBC said profits at its global banking and markets arm fell by a fifth from a year ago.