What Berkshire (or its managers) presumably like

1. Stable subscription-based business

Sirius XM has a large base of recurring revenue from subscriptions (satellite radio plus Pandora streaming) rather than one-time sales. Analysts note that over 70-75% of their revenue is subscription based.

For a value investor who likes predictability, that’s a plus.

2. Attractive valuation and “margin of safety”

The stock was trading at a relatively low multiple (for a business with stable cash flows) when Berkshire began significantly ramping up the position. For example, one write-up noted the shares were trading at about 8× earnings at that time.

Value investors like Buffett often say: buy when others are fearful.

3. Large stakeholder position / potential influence / capital return

Berkshire holds ~30-35% of Sirius XM.

At that scale, you can exert more influence, have greater oversight, and possibly benefit disproportionately if improvements happen. Also, the business has free-cash-flow capacity and has in the past done share repurchases/dividends.

4. Structural setup / corporate simplification opportunity

The timing of the investment coincided with a corporate re-structuring: the merger of Liberty Media tracking shares into Sirius XM, simplifying the capital structure. Some commentators view part of the opportunity as being in the “arbitrage” or “unlocking value” via corporate structure.

5. Upside if cyclical tailwinds revive

Some of Sirius's challenges are tied to cyclicals (auto industry, connected-car trials for satellite radio, etc). If auto sales or car-OEM integrations rebound, Sirius may benefit. Value investors may be betting on a recovery.