The nine-member jury began deliberating Wednesday in federal district court in Dallas following a trial that spanned three weeks.
The Securities and Exchange Commission accuses Cuban of using inside information to sell $7.9 million of stock in an Internet company after he learned confidentially of news that would send the share price down. The SEC wants Cuban to repay $750,000 in losses that he avoided, plus pay a penalty. It's a civil lawsuit - the basketball team owner and regular on the ABC reality show "Shark Tank" doesn't face criminal charges.
Lawyers for both sides made closing arguments Tuesday, then Judge Sidney Fitzwater read instructions to the jurors.
Aides to Cuban said Wednesday that they were told which juror was selected to lead the jury in deliberations. She is an older woman from the Dallas suburb of Rockwall who works for an insurance company and previously worked for a Texas state judge.
The woman said during juror questioning that she had served on a jury that acquitted a defendant charged with fraud. She gave no other details of the case.
The juror also said that she often watches "Shark Tank" and that Cuban "seems like a nice guy on TV."
The SEC sued Cuban more than four years after he sold his stake in Mamma.com Inc., a search engine company that was based in Canada. The company's CEO testified by video that Cuban agreed not to disclose information the CEO told him in 2004 about a pending stock offering that would dilute the value of Cuban's 6 percent stake in the company.
The CEO said that Cuban, the company's largest shareholder, acknowledged that he couldn't sell his shares on the news. He sold them a few hours later, however, before the company announced the stock offering to the public.
Cuban testified that he never agreed to keep information about the stock deal private and told the company that he would sell his shares.