MARK CUBAN: Donald Trump is 'probably not as smart as he thinks he is'

Screenshot/CNN

Mark Cuban.

Mark Cuban emphatically shut down the idea of his third-party candidacy on Monday, just days after a Washington Post report posited that anti-Trump operatives were looking to recruit the brash billionaire to run for president.

"Look, it was just an email through one of my associates and it was ... a quick response of no," he told CNN's Erin Burnett. "It's impossible for it to work."

"There's not enough time to get on the ballot," he continued. "The hurdles are just too great. It was a ridiculous effort, so I passed."

He added that there was no chance of a third-party run under any conditions.

However, the owner of the NBA's Dallas Mavericks didn't hold back his fire on presumptive Republican nominee Donald Trump.

"You know, where Donald has come from to today, you would think that he'd be more [knowledgeable] on the issues - that we would look at what he's had to say and say you know what, he's really picked up some in-depth knowledge, he's nuanced on different topics, whether it's immigration, whether it's the jobs plan, whether it's the economy, whatever it may be," he said. "But that just hasn't happened. And to me, that's a problem."

Cuban said it's clear Trump "hasn't invested the time" to gain a deeper understanding of the challenges facing the country. Trump, he opined, is "probably not as smart as he thinks he is."

"That's an issue," he said. "Now, when you have that amount of uncertainty, when there's, you know, you're flip-flopping, when you're not sure what the candidate is going to say from one thing to another, that uncertainty, you know, potentially as the president of the United States, that's the last thing Wall Street wants to hear."

When it comes to whom the billionaire business mogul would vote for, Cuban said he still has six months to make up his mind. But as of now, he said he's leaning toward Democratic frontrunner Hillary Clinton "because the devil you know is better than the devil you don't know."

"I know what Hillary's positions are," he said. "I can go to Hillary's website and there's spreadsheets, there's depth, there's analysis, there's details. Is going to Donald's website - which I have - he lists issues. He lists top-line things that he'd like to do, but he doesn't say how he's going to get there."