The company in question, First Republic, is not yet out of business, its stock still losing nearly 25% on Wall Street on Friday.

But by pledging to deposit $30 billion in First Republic's accounts, eleven major US banks sent it a lifeline.

Jamie Dimon, 67, was heavily involved in the implementation of the plan.

The boss of the largest US bank by its assets had already come to the rescue in the middle of the financial crisis in 2008, by buying Bear Stearns and some assets of Washington Mutual. His prudent management had allowed JPMorgan Chase to withstand the convulsions of the banking system rather well.

These acquisitions have made the firm grow but have also earned it a slew of complaints related to toxic financial products recovered in the process, and billions in legal costs. Jamie Dimon has said several times that he probably shouldn't have taken control of Bear Stearns.

There was no question this time of acquiring a bank in difficulty again. But Jamie Dimon spoke by phone this week with Economy Minister Janet Yellen and central bank chairman Jerome Powell, according to three sources familiar with the discussions.

"Highly respected"

The aim of their talks: to find a way to revive confidence in the banking system, shaken after the successive failures of three banks in a few days, including that of Silicon Valley Bank, the biggest bank failure since 2008.

Jamie Dimon also met in his office with Deputy Economy Minister Wally Adeyemo at the beginning of the crisis on March 10, according to the New York Times.

The government on Sunday put in place strong measures to avoid contagion, JPMorgan already agreeing to provide liquidity to First Republic.

U.S. President Joe Biden said Monday he would do "whatever is necessary" to keep banks strong.

But the situation remained fragile.

Janet Yellen suggested involving the banks themselves, together, according to a source familiar with the discussions.

Once the idea was sketched out, it was necessary to persuade the interested parties.

Bank of America, Citigroup and Wells Fargo quickly agreed, according to sources familiar with the discussions that revealed the behind-the-scenes negotiations.

To persuade other bosses, less convinced of the value of helping a competitor or the effectiveness of such a measure, Jamie Dimon and Janet Yellen took their phones.

Joe Biden's chief of staff, Jeff Zients, and Lael Brainard, director of the White House National Economic Council, were regularly briefed.

On Thursday, as First Republic's stock plunged again and after a hearing of Janet Yellen in Congress, Jamie Dimon met the minister in his office to discuss the final details.

A press release announcing the banks' concerted action was issued shortly thereafter.

Jamie Dimon "is highly respected by his peers," said Jeffrey Sonnenfeld, an expert on executive and corporate governance at Yale University.

"He speaks with expertise, authority and rare clarity," he said. "And he's been doing it for a very long time."

At the head of JPMorgan since 2005, Jamie Dimon is in fact the only boss of a major bank to be still in place after going through the financial crisis of 2008.

"No one else has his authority and credibility. Everyone picks up when they call, especially in finance," says Sonnenfeld.

His speech for First Republic was reminiscent of that of the founder of the bank he now headed, John Pierpont Morgan, in October 1907.

A prominent figure in American finance, he had provided substantial funds to try to prevent the spread of the first signs of a bank run.

As the crisis dragged on, he managed to coordinate the bosses of major financial institutions and the Treasury Department, including several dozen of them one evening in his library and not letting them go until he reached an agreement.

The episode had indirectly led to the creation of the Federal Reserve System (Fed) in 1913.

© 2023 AFP