Or, at least someone on his investment team is. Buffett's holding company now owns around $2.4 billion in Sirius XM shares, equal to roughly 30% of the total shares outstanding. Buffett's involvement alone is triggering many investors to pay closer attention.

Warren Buffett’s Berkshire Hathaway has spent another $54 million to purchase Sirius XM stock, giving it a stake of more than 35% in the satellite-radio company.