This should be an interesting one to follow. My guess is the SEC wins a Pyrrhic victory where Cuban pays a hefty fine and they come out looking very bad. Unless Cuban does something really stupid I have a hard time imagining any criminal consequences. I guess it's just a bad year for Mavericks of all kinds.

The SEC lays down the gauntlet.

Quote Originally Posted by The SEC
“As we allege in the complaint, Mamma.com entrusted Mr. Cuban with nonpublic information after he promised to keep the information confidential,” Scott W. Friestad, deputy director of the S.E.C.’s enforcement division, said in a statement. “Less than four hours later, Mr. Cuban betrayed that trust by placing an order to sell all of his shares. It is fundamentally unfair for someone to use access to nonpublic information to improperly gain an edge on the market.”
Mark Cuban responds.
Quote Originally Posted by Mark Cuban's lawyer
This matter, which has been pending before the Commission for nearly two years, has no merit and is a product of gross abuse of prosecutorial discretion. Mr. Cuban intends to contest the allegations and to demonstrate that the Commission’s claims are infected by the misconduct of the staff ofits Enforcement Division. Mr. Cuban stated, “I am disappointed that the Commission chose to bring this case based upon its Enforcement staff’s win-at-any-cost ambitions. The staff’s process was result-oriented, facts be damned. The government’s claims are false and they will be proven to be so.”
Juicy conspiracy theory angles broken down here and here.

Interesting legal analysis here.