DALLAS — The government’s insider-trading case against billionaire and Dallas Mavericks owner Mark Cuban is heading toward an end.

After six days of testimony, closing arguments are expected today in a Dallas federal court.

The Securities and Exchange Commission accuses Cuban of avoiding $750,000 in losses by selling his shares in an Internet search engine company after the CEO told him privately about a planned stock offering that would cut the value of Cuban’s shares. Cuban says there never was a confidentiality agreement, and he denies any wrongdoing.