Jamie Dimon, chief executive officer of JPMorgan Chase, attends a Strategic and Policy Forum meeting with U.S. President Donald Trump, not pictured, in the State Dining room of the White House in Washington, D.C. last February.

Whenever the inevitable question arose at events both public and private, Jamie Dimon would pause and smile before ruling out a presidential run.

But the billionaire J.P. Morgan Chase CEO actually spent much of 2018 weighing whether he should give it a shot, according to people with knowledge of the situation.

As last year drew to a close, however, Dimon concluded that he wouldn't run. With the Republican nomination unavailable and the leftward lean of the Democratic Party making the election of a Wall Street tycoon unlikely, Dimon begrudgingly decided that he would continue to serve his country from his current positions.

Dimon's thought process played out in public, at times. In September, at an event held at his bank's Park Avenue headquarters in New York, Dimon, 63, took several swipes at President Donald Trump and blurted out that he thought he could beat him in an election.