Billionaires Carl Icahn and Mark Cuban are butting heads on social media over Donald Trump.
On Monday, Cuban, owner of the Dallas Mavericks, called out Icahn for continuing to invest in companies despite corporate regulations that Icahn had described as "strangulating."
Last week, Icahn criticized Hillary Clinton following the Democratic presidential nominee's speech for failing to address "strangulation regulations." The chairman of Icahn Enterprises said Clinton's speech was a "mishmash of contradictions."
Icahn defended himself saying that regulations have lowered corporate productivity and competitiveness. These regulations discourage investors from making capital investments, he argued.
Cuban has been bashing Trump for months. At a rally for Clinton and her running mate, Tim Kaine, the billionaire said "hello" to the GOP nominee in Russian. On Monday, Cuban tweeted that although he likes Icahn, he isn't afraid to call him out for being "wrong about Trump."
Last month, Icahn told CNBC that he thinks Trump is "right on" about the economy. Icahn has continued to reiterate his support for the GOP nominee, despite gaffes such as Trump's comments about a Mexican-American judge.
Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban as a judge.