Warren Buffett's Successor, Greg Abel, Just Plowed $27 Million Into a Virtual Monopoly (No, Not Alphabet!)

It's been a year of significant change for trillion-dollar conglomerate Berkshire Hathaway (NYSE:BRKA)(NYSE:BRKB). Longtime leader Warren Buffett retired as CEO at the end of last year, handing the reins to the company's day-to-day operations and its $364 billion investment portfolio to his understudy, Greg Abel.

Abel wasted little time making his mark. He completely overhauled Berkshire's investment portfolio in the first quarter and built up a significant position in Google parent Alphabet (NASDAQ:GOOGL)(NASDAQ:GOOG). But Alphabet isn't the only virtual monopoly that the Oracle of Omaha's successor is piling into. Abel is also adding to Berkshire's already sizable stake in satellite-radio operator Sirius XM Holdings (NASDAQ:SIRI).

Berkshire's new boss, Greg Abel, has found value amid a historically pricey stock market. Image source: Getty Images.

Berkshire's Greg Abel is getting "Sirius"

Usually, investors have to wait until money managers file Form 13F (due Nov. 16) to get an under-the-hood look at what they've been up to. But when beneficial owners (those who hold 10% or more of a public company's outstanding shares) make a trade, they're required to report it via a Form 4 filing within two business days.

Between Oct. 30 and Nov. 3, Abel and his team purchased 924,281 shares of Sirius XM stock for about $27 million. This increased Berkshire Hathaway's stake in the company to more than 125.7 million shares (over 37% of Sirius XM's outstanding shares are held by Berkshire).

Been a while. $BRK.B once again a buyer of $SIRI after 3Q results. 35% owner and significant repurchases coming next year and beyond going to create a $DVA situation where Berkshire quickly heads towards 50% ownership.

— Andrew Coye (@andrewcoye) November 4, 2026

The obvious lure of buying Sirius XM stock is its status as a legal monopoly. Although it faces plenty of competition for listeners among terrestrial and online radio providers, Sirius XM is the only licensed satellite-radio operator in the country. This affords it a healthy degree of pricing power over its subscription services.

But it's not just Sirius XM's virtual monopoly status that has Berkshire's current and former bosses intrigued.

A strong argument can be made that Sirius XM's revenue mix is far more important than its monopoly status. Whereas most traditional radio companies rely almost exclusively on advertising revenue to keep the lights on, Sirius XM has generated 21% of its net sales from ads through the first nine months of 2026 and 76% from subscriptions.

When recessions inevitably occur, ad revenue often dries up quickly, putting some traditional radio operators in a bind. This isn't the case for Sirius XM, given that subscribers are far less likely to cancel their services during an economic downturn. In other words, Sirius XM's cash flow is much more consistent than its peers.

Sirius XM also enjoys some level of cost predictability that traditional radio operators don't. While royalty and programming costs are going to vary from quarter to quarter, the company's equipment and transmission expenses should remain stable regardless of how many subscribers it has. This is a recipe for margin expansion over time.

Lastly, Sirius XM offers a value proposition that Warren Buffett's protégé has struggled to find amid a historically expensive stock market. Even though Sirius XM's supercharged growth days are in the rearview mirror, mindful spending, coupled with low-single-digit growth and premier subscription pricing power, has the company trading at just 10 times 2027's forecast earnings.

Virtual monopolies are quickly becoming a staple in Berkshire Hathaway's portfolio under Greg Abel.

Sean Williams has positions in Alphabet and Sirius XM. The Motley Fool has positions in and recommends Alphabet and Berkshire Hathaway. The Motley Fool has a disclosure policy.