If Cuban did not sell his shares, then he would have had $750,000 in losses according to the accusations.  Cuban responded to the allegations on his blog:

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.

Cuban recently invested in Bailoutsleuth.com, a blog that tracks how the government bailout money is spent.

“Historically, the SEC has liked to make examples of well-known individuals — such as Martha Stewart — because it attracts attention to the subject,” stated Alexander Bono, Chair of Securities Litigation at Schnader Harrison Segal & Lewis.

Cuban is currently the owner of the Dallas Mavericks and Chairman of HDNet.  Cuban is an owner in IceRocket, a former partner at RedSwoosh, and invested in Weblogs, Inc.  Most of Cuban’s wealth was generated from Yahoo!’s acquisition of broadcast.com for $5.9 billion.