Viacom is suing a group of former Harmonix stockholders, seeking a refund of over $131 million that it paid out, which it calls a "contractual overpayment." According to court documents, Viacom paid stockholders a total of $149,770,149 in 2007, based on an estimate of earnings; it then said that the real amount due was $131 million less than that, and asked for the remainder back, claiming that the payments were made "on account."

Harmonix shareholders brought their own suit against Viacom last year on a related topic. They actually claimed Viacom owed more in earn-out payments from the sale of Rock Band games. Both parties can't be right!