PHILADELPHIA — Billionaire businessman Michael Bloomberg delivered a stinging rebuke of GOP presidential nominee Donald Trump at the Democratic National Convention Wednesday night, calling him a “dangerous demagogue.”

“Trump says he wants to run the nation like he runs his business. God help us,” said Bloomberg, a former New York City mayor who is unaffiliated with any political party. “I’m a New Yorker. I know a con when I see one.”

Bloomberg on Trump: 'I Know a Con When I See One'

Bloomberg said there is “no doubt in my mind” that Democratic nominee Hillary Clinton is the “right choice” in the Nov. 8 election. He told fellow independents that their votes mattered and he urged the nation to “elect a sane, competent person with international experience, a unifier.”

“Hillary Clinton understands this isn’t reality television,” he said. “This is reality.”

A spokeswoman for Trump didn’t immediately respond to a request for comment.

An expanded version of this report appears on WSJ.com.