Mark Cuban. AP Photo/Carolyn Kaster

Mark Cuban questioned Donald Trump's wealth during an interview on WABC's "The Bernie and Sid Show," BuzzFeed reported.

The brash business mogul and owner of the NBA's Dallas Mavericks said that Trump's lack of transparency makes it particularly difficult to determine what the presumptive Republican presidential nominee is really worth.

He also ripped Trump for being willing to put his name on "nonsense" such as Trump Steaks, a since-discontinued brand that was sold through The Sharper Image consumer catalog.

"I know what I'm good at, and I know what I'm not good at," Cuban said. "I'm not so sure Donald knows what he's not good at."

He said that Trump was good at putting his name on properties and licensing his name on hotels, although he added that Trump's lack of transparency makes it difficult to tell how much he's been able to profit from those deals.

"He's good at that," Cuban said. "Whether or not that's made him a billionaire, I don't know."

Cuban also said that he went over Trump's recent FEC filings — the ones Trump's campaign claimed displayed his "massive" fortune.

But the star of ABC's "Shark Tank" said that he saw a different story reading through the report.

He said:

I don't think he's very good at brands for non-real-estate products. And, to me, it's more a reflection of desperation. So when you're putting your name on steaks, and you're putting your name on water, you're putting your name on playing cards, you're putting your name on all this nonsense, right? You're not going to make big bucks, no matter what. It's not like Trump Steaks were going to make him $100 million. It's not like it was going to make him $5 million.

"I asked, 'What the hell are you doing? Are you that desperate for money?' Seriously," Cuban said.

After reading Trump's FEC filing, Cuban said that "it's not even close" as to who has more in liquid assets between the two.

"I do," he said.

He continued:

Before all the Trumpians jump on me on who has more money, the reason I know is when you file your federal election-campaign reports, you have to list all your cash and liquid securities and bonds. You have to list them one by one. So we know without any question that, as of May 27, Donald doesn't have more than $165 million in cash and securities and bonds.

And trust me, I've got a lot more than that in cash, securities, and bonds. And so you know, I'm willing to bet dimes against dollars that that's pretty much what he's got.

Cuban told Business Insider in a Wednesday email that "liquidity is a good proxy for relative net worth."

"You can't lie about cash, stocks, and bond values," he said.

Cuban has flirted with presidential politics in recent weeks. He generated additional buzz after Hillary Clinton expressed openness to him serving as her running mate during a "Meet the Press" episode, during which Cuban also said that he'd be intrigued by the possibility.

The mogul has since said that Clinton's team has reached out to his team about setting up a meeting, although it wasn't clear if it was to talk about the possibility of serving as a running mate.