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."
@mcuban: @Carl_C_Icahn sure hasnt stopped you from investing in companies Carl , has it ? Regs can improve, no doubt, but trump plan is a disaster
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.
@Carl_C_Icahn: @mcuban Cap spending is way down b/c companies r worried about onerous regs - which is diminishing productivity & our ability to compete
@Carl_C_Icahn: @mcuban it sure has stopped me and thousands of others from making capital investments in companies.
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."
@mcuban: @RobertBryan4 @BWJones @_zruss @Carl_C_Icahn I like Carl. Doesn't mean I won't give him shit when he is wrong . And he is 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.