You could say Jamie Dimon is the Houdini of Wall Street, wiggling out of one embarrassing situation after another. But can he maneuver out of his most recent tight spot?

Two companies that advise shareholders on corporate governance are supporting proposals to oust some of JPMorgan Chase & Co.'s board. They also favor splitting Dimon's roles as chairman and chief executive officer into two.

Calls for a fresh board and for Dimon to share power have grown since last May, when the bank disclosed a $6.2 billion derivatives trading loss.

Today, Glass Lewis & Co., a proxy advisory company, said it backs the removal of six of the board's 11 directors as well as the splitting of Dimon's jobs. It cited ongoing federal investigations of the bank, questionable risk-management practices and the board's seeming obliviousness to mounting troubles.

Glass Lewis recommends voting against an all-star board, including James A. Bell, former chief financial officer at Boeing Co.; Crandall C. Bowles, chairman of Springs Industries Inc. and wife of Erskine Bowles; and David M. Cote, CEO of Honeywell International Inc.

The advisory firm would also remove James S. Crown, president of Henry Crown & Co.; Ellen V. Futter, president of the American Museum of Natural History; and Laban P. Jackson, CEO of Clear Creek Properties Inc.

Bell, Bowles and Jackson are on the board's audit committee. Cote, Crown and Futter sit on the risk-policy committee, which oversees the bank's management of its risks. Last week, Institutional Shareholder Services, another proxy advisory firm, announced that it favors reducing Dimon's role and removing Cote, Crown and Futter.

Anne Simpson, a senior portfolio manager at the California Public Employees Retirement System, tells Bloomberg News that bank directorships are "no longer a job for the well-meaning amateur." She has a point. Mismanaging the gargantuan risks posed by the biggest banks, for example, by not understanding its derivatives book, can wipe out a bank's entire capital and threaten the health of the global economy.

The bank is lobbying shareholders to vote against a separate chairman, saying that Dimon's dual roles remain the "most effective leadership model." This week, Warren Buffett backed Dimon.

The Senate Permanent Subcommittee on Investigations said in a March report that the bank dodged regulators, misled investors, manipulated risk models and pressured traders to overvalue positions in an effort to hide mounting losses on derivatives bets. The blunders prompted probes in the U.S. and overseas, and regulators imposed sanctions after concluding the bank had weak internal controls. A board investigation, however, found that mistakes couldn't be attributed to the board.

While advisory services can be influential, their recommendations aren't binding. Nor do successful shareholder proposals tie the hands of corporate management. But the pressure of a large number of unhappy shareholders can force a CEO to act. The bank will announce the vote results at its annual meeting on May 21 in Tampa, Florida.

Last year, Glass Lewis and ISS endorsed a similar proposal to split Dimon's jobs. It won 40 percent of the vote -- a large number in the proxy-voting context; institutional investors tend to support management in such battles.

BlackRock Inc., the largest holder of JPMorgan stock through the numerous mutual funds it manages, could be the decider. Last year it voted with Dimon. If BlackRock switches sides this year, Dimon could be forced to share power.

(Paula Dwyer is a member of the Bloomberg View editorial board. Follow her on Twitter.)