Dick Kovacevich, former chairman and CEO at Wells Fargo, blasted GOP presidential front-runner Donald Trump on Monday, saying he would not vote for the billionaire businessman.

"I think he's obnoxious. He's a bully. He's a narcissist. He debates on basis of personal insults and trivial soundbites," Kovacevich told CNBC's "Squawk Box." "I don't even know what his policies are. The times he comes out with policies, I don't think they make any sense. I would not vote for Donald Trump."