Dallas Mavericks owner Mark Cuban looked spiffy in a blue suit as he arrived for federal court.
Cuban, sporting a black suit rather than his usual T-shirt and jeans, declined to comment afterward.
Before the proceedings started, Cuban joked with his brother Brian Cuban, mentioning how his back was stiff after going to the batting cages. The billionaire also managed to crack a few grins before the judge entered the courtroom.
After the hour-long hearing, the normally animated and combative billionaire declined comment.
"Just write about how good I look in my suit," he said in the hallway outside the courtroom. "I haven't worn it in 20 years."
Later, as he prepared to drive away in a black Cadillac Escalade, he told reporters to note that he was "driving American" as well as a hybrid vehicle.
The SEC alleges Cuban engaged in insider trading when he sold shares in an Internet search engine company, Mamma.com Inc., after receiving confidential information about a private offering. Selling his 600,000 shares, which represented a 6.3-percent stake in the company, allowed Cuban to avoid a loss of $750,000, according to the SEC.
Cuban's legal team doesn't acknowledge those facts as true. But even if they are, Cuban's lawyers contend, he didn't engage in insider trading because he wasn't legally an "insider."
A copy of the SEC's case can be seen here.
The rebuttal made by Cuban's legal team can be seen here.
Omar Villafranca contributed to this report.