Liberty Media is continuing its slow and steady acquisition of shares in SiriusXM as part of the private equity group's plan to eventually hold a majority stake in the satcaster. The Wall Street Journal reports that Liberty announced in a SEC filing this week that it bought almost 90 million more shares in SiriusXM at an average price of $2.50 each, totaling $225 million.

Liberty also agreed to buy roughly 41 million more shares of the satcaster via a forward purchase contract that expires in October. Liberty already held 46.2 percent of SiriusXM but according to the WSJ, these new moves will increase its share to 48 percent.

Last week, Liberty Media announced it will spin off the cable network Starz into a separately traded public company. Analysts believe this move may be yet another step towards Liberty acquiring a bigger stake in SiriusXM.