PHILADELPHIA — Business mogul Michael Bloomberg eviscerated fellow New York City billionaire Donald Trump on Wednesday night, saying "I'm a New Yorker, and I know a con when I see one."

"I understand the appeal of a businessman president. But Trump's business plan is a disaster in the making. He would make it harder for small businesses to compete, do great damage to our economy, [and] threaten the retirement savings of millions of Americans," the former New York City mayor said in a speech at the Democratic National Convention. "Trump is a risky, reckless, and radical choice. And we can't afford to make that choice."

"Most of us who have created a business know that we're only as good as the way our employees, clients, and partners view us. Most of us don't pretend that we're smart enough to make every big decision by ourselves. And most of us who have our names on the door know that we are only as good as our word, but not Donald Trump," said Bloomberg, who emphasized he's an independent, as the crowd cheered throughout his speech.

Trump, the Republican presidential nominee, has been using his business acumen to appeal to voters, attempting to show off his leadership skills.

"Throughout his career, Trump has left behind a well-documented record of bankruptcies, thousands of lawsuits, angry shareholders and contractors who feel cheated, and disillusioned customers who feel ripped off. Trump says he wants to run the nation like he's run his business. God help us," Bloomberg said.

On Sunday, Bloomberg, said he'd endorse Democratic nominee Hillary Clinton because he was concerned about Trump's candidacy. Now back running his financial data and media empire, Bloomberg LP, the 74-year-old billionaire himself once considered an independent run for president but opted to stay on the sidelines.

Bloomberg's endorsement was a surprise to many, since he hasn't been a Democrat since 2000. He bolted for the GOP in 2001, ahead of his first mayoral campaign. In 2009, however, Bloomberg left the Republican party and ran as an independent to win his third consecutive term.

Of course, an endorsement of a figure so closely aligned with the interests of Wall Street may not go over well with supporters of Bernie Sanders who have come to support Clinton.

Previously, he endorsed Obama in 2012. He did not endorse anyone in 2008, and supported George W. Bush in 2004.

In his Wednesday speech, Bloomberg recognized that he and Clinton did not always agree, but admitted "she is the right choice ... in this election."

"Hillary Clinton understands that this is not reality television; this is reality. She understands the job of president. It involves finding solutions, not pointing fingers, and offering hope, not stoking fear," he said.

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