Lee Raymond, the senior independent director at JPMorgan Chase, told shareholders not to risk a "disruptive" vote to strip Jamie Dimon of his chairmanship in a robust letter ahead of a crucial annual meeting in two weeks. It is the first public intervention from Mr Raymond during a tumultuous period at the bank, with investor advisory groups pushing for Mr Dimon to lose his role as chairman, in part because of the "London Whale" trading fiasco. Mr Raymond and William Weldon, head of the board's corporate governance committee, also defended each of the directors, some of whose expertise has come into question. "The board takes the concerns raised by shareholders very seriously," they said. The uncompromising stance of the JPMorgan board comes in spite of dissatisfaction about its performance in the wake of the "Whale" affair when traders lost more than $6bn betting on credit derivatives and regulators and members of Congress drew attention to lax risk management at the bank. Activist investor groups such as the American Federation of State and County Municipal Employees have led the calls for change to the board membership and structure but even institutional investors have privately expressed unhappiness. The directors" letter said focus on the activities of the traders was judging the issue "too narrowly" and pointed to the bank's better-than-average stock performance. "It is two imperial CEOs defending a third imperial CEO," said Dieter Waizenegger, executive director of CtW Investment Group, which advises union pension funds, adding their response was late and inadequate. Mr Raymond is the former chairman and chief executive of ExxonMobil. Mr Weldon is the former chairman and chief executive of Johnson & Johnson. Mr Raymond's decision to come out strongly and publicly in favour of the status quo also differs markedly from Goldman Sachs, which quelled investor demands for an independent chairman by increasing the power of its senior independent director. With 10 days until JPMorgan's meeting in Tampa, the company has received about a quarter of the votes, according to people familiar with the matter. Last year just over 40 per cent of the vote went in favour of an independent chairman but that was before the full ramifications of the London Whale affair were known.