A coalition of shareholders with more than $820 million invested in banking giant JPMorgan Chase will ask other investors this spring to support having an independent board chairman, ousting CEO Jamie Dimon from that role.

The investors filing the shareholder proposal for the bank's annual meeting in May includes the AFSCME Employees Pension Plan, the Connecticut Retirement Plans and Trust Funds, Hermes Equity Ownership Services, and the NYC Pension Funds. In a joint statement, they said that the so-called London Whale trades, where billions were lost with a risky synthetic credit portfolio, and “mounting regulatory sanctions” have reinforced the need for improved, and independent, board oversight. Dimon's dual role as CEO and board chairman was cited as a “clear conflict of interest” with the potential to “adversely affect the value of their investments.”

“Without an independent board chair, JPMorgan will be unable to restore investor confidence and ensure future compliance — both integral to protecting and creating long-term value,” said New York City Comptroller John Liu, custodian and trustee of the New York City Pension Funds, which holds approximately $480 million in JPMorgan shares.

"At the heart of the company's failures in managing risk and developing a strong corporate culture of ethics, accountability and transparency is the question about independence,” Connecticut Treasurer Denise Nappier, principal fiduciary of that state's $26 billion pension funds, said. “It is impossible to imagine how board oversight of the company's affairs will be strengthened while CEO Jamie Dimon leads the very board that is charged with overseeing his own shortcomings.”

The groups claim that separation of the CEO and board chair duties is “widely acknowledged to increase a company's accountability and performance” and that businesses that maintain an independent board chair outperform those that do not. A June 2012 report by GMI Ratings found that five-year shareowner returns were nearly 28% higher at companies with a separate CEO and board chair.

“We believe that a CEO who also serves as chair operates under a conflict of interest that can result in excessive management influence on the board and weaken the board's oversight of management,” the shareholder proposal says. The independence requirement “shall apply prospectively so as not to violate any contractual obligation at the time this resolution is adopted,” it explains, adding that compliance with this policy is waived if no independent director is available and willing to serve as chair.