Looks like old Viacom chief Sumner Redstone is the first media mogul to take a significant hit from the present awful economic climate for media companies (Pictured: Viacom's stock chart for the last year). And by "significant hit," we mean "being forced to sell $400 million worth of stock."

Sumner Redstone, the billionaire who controls Viacom Inc. and CBS Corp., is being forced to sell about one-fifth of his stake in the media companies to meet loan terms at his holding company, National Amusements Inc. The sale plan followed a statement from Viacom today that third-quarter earnings missed analysts' estimates, sending the stock down as much as 28 percent. CBS fell as much as 15 percent after cutting its profit forecast this year.

We already played "Which magazine will fold next?" Now let's play "Which mogul will be hugely inconvenienced next?" I guess Sam Zell. [Bloomberg]