For a moment there, Donald Trump was starting to sound a lot like Bernie Sanders.

The billionaire Republican front-runner assailed hedge fund managers in a Sunday appearance on CBS' Face the Nation in which he portrayed himself as a champion of the middle class. 

"They're paying nothing. And it's ridiculous," Trump said of those who make a living running hedge funds. "I want to save the middle class. You know, the middle class—the hedge fund guys didn't build this country. These are guys that shift paper around and they get lucky. And, by the way, when the market collapses, like it is now, the market is going down, they're losing a fortune."

Sanders, the leading challenger to Hillary Clinton for the Democratic presidential nomination, has routinely gone after hedge fund managers during his populist campaign.

Taxation of hedge fund earnings has not been a central focus of Trump's campaign. Still, on Sunday, Trump took aim at those who profited from the investment strategy. 

"Half of them, look, they're energetic, they're very smart, but a lot of them, it's like they're paper pushers. They make a fortune, they pay no tax. It's ridiculous, OK? This—and some of them are friends of mine. Some of them, I couldn't care less about. It's the wrong thing," Trump said. "The hedge fund guys are getting away with murder. They're making a tremendous amount of money. They have to pay taxes. I want to lower the rates for the middle class. The middle class is the one, they're getting absolutely destroyed. This country doesn't have—won't have a middle class very soon."

Clinton has also woven an attack on hedge fund managers into her stump speeches. 

“Something is wrong when CEOs earn more than 300 times than what the typical American worker earns and when hedge fund managers pay a lower tax rate than truck drivers or nurses,” Clinton said in May while campaigning in Cedar Falls, Iowa. 

The rhetorical similarities between Trump and his would-be Democratic rivals have given Jeb Bush an attack opening. 

“He was a Democrat longer than he was a Republican,” Bush said last week during a town hall in New Hampshire. “He's given more money to Democrats than he has to Republicans.”