Mark Cuban: Trump has a cash problem, and he'll have to 'grovel' to donor class

Mark Cuban claims Trump lacks money to fund campaign

Billionaire Mark Cuban fired a new barrage against Donald Trump on Wednesday, saying the presumptive GOP presidential nominee will "have to grovel" to donors because of his campaign's cash situation.

He made the comments on Twitter:

Trump has claimed repeatedly that because of his wealth, he doesn't have to make promises to wealthy donors as traditional politicians do.

Trump made that claim again Tuesday night while appealing to supporters of Sen. Bernie Sanders who may be looking for a general election candidate now that Hillary Clinton has become the apparent Democratic presidential nominee.

"I beat a rigged system by winning with overwhelming support — the only way you could've done it," Trump said. "We can't fix a rigged system by relying ... on the very people who rigged it."

Cuban has previously criticized Trump, questioning the real estate developer's claims that he's a billionaire, and saying he doesn't think Trump is "a reflection of a CEO or a reflection of an entrepreneur."

The Trump campaign did not immediately respond to a CNBC request for comment.

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban as a judge.