The deal talks went down to the wire, according to two sources familiar with the situation.
Four bidders, including JPMorgan, made it to the final rounds of the auction on Sunday night, one of the sources said.
The final deal, announced around 3:30 a.m., cements Dimon's reputation as one of Wall Street's most powerful bankers.
JPMorgan started a process internally, which looked at various options for First Republic, including an acquisition, according to a source familiar with the matter.
The auction dragged out through the night as the FDIC's advisors examined each bid on its merits, a source familiar with the matter said.