WASHINGTON (AP) — President Donald Trump is scoffing at a claim by Jamie Dimon, the JPMorgan Chase JPM CEO, that he could beat Trump in an election. Trump tweeted Thursday that Dimon is a “nervous mess.”

Trump says the powerful Wall Street banker “doesn’t have the aptitude or “smarts” & is a poor public speaker & nervous mess – otherwise he is wonderful.”

Dimon caused a stir Wednesday when he said he’d be able to beat Trump. Dimon quickly walked backed those comments and said he isn’t running for president. He said his comments were prompted by frustration over Washington gridlock.

Dimon also said he is just as tough as Trump and smarter.

Trump tweeted, “I’ve made a lot of bankers, and others, look much smarter than they are with my great economic policy!”