Did Bill Miller sell out Barry Diller?

Word now comes that Liberty, former cable baron John Malone's company, has opportunistically paid $340 million for 14 million shares in Barry Diller's IAC, raising its stake to 30 percent. IAC, too, repurchased 6 million shares at the same time. That means that Diller must have begrudgingly consented to the sale; at the same time, he reached an agreement that prevented Malone from taking a bigger stake in the online conglomerate. But who was the seller?

An obvious guess: Bill Miller, Legg Mason's chief investment officer, is a famed tech investor, most noted for making an early bet on Amazon.com. But as a stock pick, IAC, has been a stinker, dropping 38 percent over the past year. And Legg Mason is one of only two institutional investors who could have easily parted with 20 million shares. (Lord Abbett, another mutual-fund company, is the only other.)

Miller has been unwinding his stake since March, so a sale would not be surprising. But it's a blow to Diller nonetheless. The media mogul has sought to boost his company's shares by splitting it into five more focused parts, targeting specific sectors of e-commerce. Shareholders would then choose which ones they want to invest in. Whoever sold that large stake to Liberty, whether Miller or anyone else, has signalled an obvious choice: none of the above.