Jamie Dimon has run JPMorgan Chase since 2005. Two decades at the top of one bank is unusual anywhere; doing it while making that bank among the largest and most profitable in the world is why he is the most influential figure in global finance.

Crises made the reputation. JPMorgan came through the 2008 meltdown in better shape than most of its peers, and the phrase Dimon repeated throughout — fortress balance sheet — stopped being a slogan and became how the institution is actually run.

In every crisis, the same instinct: keep a fortress balance sheet, and be the bank still standing when the storm clears.

His annual shareholder letters wander well past banking into the economy, geopolitics, regulation and public policy. Presidents read them. That is a statesman's platform, not a chief executive's.

Succession is the question nobody in finance can stop asking, because he has been there so long that the bank and the man are difficult to separate. What he leaves behind is an institution built to survive — and a very loud argument about how capitalism ought to work.

Dimon studied at Tufts University and Harvard Business School and spent his early career as a protégé of Sandy Weill, helping build the group that became Citigroup. Weill fired him in 1998. Two years later Dimon became chief executive of Bank One in Chicago, which he cleaned up and then sold to JPMorgan Chase in 2004, a deal that put him in line to run the combined bank.

In 2008 JPMorgan bought Bear Stearns with backing from the Federal Reserve, and then the banking operations of Washington Mutual after its collapse, adding thousands of branches. In 2023, during another bout of bank failures, it acquired most of First Republic Bank. Each rescue made it larger and pushed it closer to the role of a quasi-public institution.

The record includes setbacks. The London Whale trades of 2012, in which a trader in the bank's chief investment office ran up losses of more than six billion dollars, led to regulatory fines and congressional hearings. Dimon has also had two serious health scares, throat cancer in 2014 and emergency heart surgery in 2020, and returned to work after both.