Last week, Trump said in a press release his net worth exceeded $10 billion.
"While it's a big number, it's not an important number. In fact, it's a play number," Cuban said via Cyber Dust, his own messaging app which, much like Snapchat, deletes the message's content after a specific time period.
"Let's say you own a painting that gets appraised at 10 billion dollars. That gives you a net worth of 10 billion. But that does not mean you have a lot of cash," Cuban added. "In fact, it's possible to be worth billions, but not be able to pay your rent."
"How much cash does Donald have? We don't know for sure. But we do know whatever cash he has, post his several corporate bankruptcies, he hates to spend it. And the one thing about the race for the presidency is that it takes a lot of CASH. Not net worth. Cash. Cash. Cash."
The latest poll conducted by The Washington Post and ABC News had Trump ahead of the field by at least .
Trump also made headlines over the weekend after saying that U.S. Sen. John McCain, a former prisoner of war, was not a hero. "He's a war hero because he was captured. I like people who weren't captured," Trump said.
As for why Cuban decided to make the remarks? "When a presidential candidate makes his net worth a topic, it's easy to have a reason to discuss," Cuban told CNBC. Nevertheless, he added that he likes Trump and has met him personally.
Trump did not immediately respond to CNBC's request for comment.