Liberty Media Corp. plans to spin off its 50% stake in Discovery Communications Inc. to the public -- a move that could shake up the rigid ownership structure of the cable programmer.
Liberty says in an SEC filing that it will combine Discovery and its Ascent Communications subsidiary into a new company called Discovery Holding Company.
Discovery is the elephant of this deal, with Morgan Stanley media analyst estimating that the 50% stake is worth $5.8 billion and 100% of Ascent just $300 million.
Liberty has an earnings conference call scheduled for 11 a.m. ET to discuss earnings and explain the move.
Immediate speculation: Liberty chairman John Malone is trying to rattle the other owners of Discovery-- Cox and Advance Newhouse -- prodding them to sell their stakes or take Discovery itself public.
Both Newhouse and Cox officials have long maintained they have no interest in selling their stakes, but Liberty is in a long process of unwinding assets, looking in part to sell properties to News Corp.
Liberty expects to complete the spin-off by fall, if regulators and the IRS approve.