Pirc, which advises investors worth £1.5 trillion, has emerged as the latest backer of a shareholder revolt at Credit Suisse and is also opposing an HSBC bonus plan, ahead of what could be an uncomfortable few days for some company boards.

Both banks hold their annual shareholder meetings on Friday, April 28. Protest has been building against Credit Suisse's pay plans for some weeks, led by Swiss ethical-investment group Ethos Funds and helped along by the influential shareholder advisers ISS.