Fortune magazine reported Dimon said a polite "no thank you" after he was offered the role of US treasury secretary.
Reports first surfaced shortly after Trump's election that Dimon was tipped for the top job at the treasury - although he had previously said he wasn't interested in the role.
That didn't stop shares in JP Morgan falling 2.5 per cent last night as rumours swirled that Dimon will take on the role, although other banking bigwigs have been linked to the job as well - including Goldman Sachs partner Steve Mnuchin.
Perhaps Dimon's feelings were just hurt? Trump has previously displayed characteristically conflicting views of him, tweeting on one occasion that he is a "great banker" - but a year later calling a decision to settle a $13bn fine with the US government a "terrible move".
Jamie Dimon of JPMorgan Chase had a bad week, but will fully recover. He is a good guy and a great banker.— Donald J. Trump (@realDonaldTrump) May 14, 2012
Jamie Dimon just gave away $13B to government in settlement. Terrible move & bad precedent. Could have done much better by fighting.— Donald J. Trump (@realDonaldTrump) November 19, 2013
Shares in JP Morgan edged up 0.06 per cent to $77.40 in pre-market trading in New York at the reports the CEO would be staying put.