The U.S. Department of Justice is investigating a breakfast meeting between Activision CEO Bobby Kotick and investor Alexander von Furstenberg, as part of its probe into possible insider trading related to Microsoft's $69 billion takeover bid for Activision, per the WSJ.

Why it matters: There's often unusual options trading activity ahead of big merger announcements, but the Feds either look the other way or nab small-timers. If there's a real case to be made here, it would be the highest-profile in memory.

Background: Von Furstenberg and media moguls Barry Diller and David Geffen bought Activision options at $40 on Jan. 14, shortly after the breakfast and just four days before Microsoft said it would buy the gaming giant for $95 per share.

• Von Furstenberg is a longtime friend of Kotick's and is Diller's stepson.

The defense: The 80-year-old Diller basically used an "I'm not that dumb" defense in his statement to the WSJ, calling the situation a coincidence and argued he wouldn't have waited until so late in life "to participate in so obvious a fraud."

• It's also worth noting that the options were technically in the money before the merger announcement, although the deal added tens of millions of dollars in possible profit.

The bottom line: Activision and Microsoft each have billions of reasons not to terminate their deal, due to breakup fees, no matter how messy it may get.