Investors in JP Morgan have been urged to vote in favour of splitting the role of chief executive and chair at America’s largest bank, amid concerns over the power wielded by its billionaire boss Jamie Dimon. ISS and Glass Lewis, which issue advice to some of the world’s biggest fund managers on how to vote at annual investor meetings, have thrown their weight behind a shareholder resolution that would ensure two separate people hold the office of chair and chief executive “as soon as possible”. Investors are due to vote on the resolution at the bank’s annual general meeting on 19 May. Dimon, who is worth an estimated $2.6bn (£1.9bn), has held the dual role for two decades. Holding the two most senior roles in a company is widely frowned upon in corporate governance circles, particularly in Europe, but not banned. “The size and complexity of JP Morgan suggests that it is difficult for any one person to run both the company and the board,” ISS said in its shareholder report.…