Via NYT:

A boardroom drama has been unfolding over the last couple of months between Sirius XM Radio and its biggest shareholder, Liberty Media.

There has been no mystery about Liberty’s intentions — it wants to take Sirius over — but in a government filing on Thursday, the company laid out its plans concerning Sirius, which include buying more stock and replacing the members of the board.

In March, when its stake in Sirius amounted to 40 percent, Liberty asked the Federal Communications Commission to recognize it as having “de facto control” over Sirius, despite its minority stake. The agency denied the request, and Mel Karmazin, Sirius’s chief executive, later mocked the attempt, saying that “40 is not the new 50.”

Liberty — a media conglomerate controlled by John C. Malone with holdings in the Starz television channel, Barnes & Noble and Live Nation Entertainment — then began increasing its holdings in Sirius; it now has a 46.2 percent stake.

In its filing with the Securities and Exchange Commission on Thursday, Liberty said it asked the F.C.C. this week to reconsider its decision. (Even with a majority ownership, Liberty would need regulatory approval to take over Sirius’s broadcast licenses.) If it gets that O.K., the company added, it “intends to assert control” over Sirius by buying enough additional stock “that would enable it to replace the entire board of directors by unilateral action.”

When Liberty saved Sirius from bankruptcy in 2009 with a $530 million loan, it got its original 40 percent stake in return, but agreed not to make any attempts to take over the company for three years. That agreement expired in March.

What a Liberty takeover would mean for Sirius — and for Mr. Karmazin — is unclear. Some analysts have suggested that Liberty might spin off its stake and merge Sirius with another company, which would allow the company to save money on taxes. But beyond the stock plan, Liberty has not elaborated.

In a response filed with the S.E.C., Sirius raised procedural questions about Liberty’s proposals, saying that stockholders could not call general meetings and that the board had not been notified of any changes. The company also said that it has been in discussions with Liberty but that “there is no assurance that these discussions will result in any specific action or transaction,” and said it would not comment further about the talks.

Since news of Liberty’s takeover attempts emerged, Sirius’s stock has declined about 21 percent, from $2.40 at the beginning of April to a close of $1.89 on Wednesday. By midday Thursday it was up slightly on Nasdaq.