SiriusXM only accounts for 1.1% of Berkshire Hathaway's total portfolio.
While its portfolio stake is small, Berkshire owns 37% of SiriusXM.
SiriusXM has signed a promising audio advertising deal with YouTube.
Sitting quietly in Berkshire Hathaway's portfolio is SiriusXM Holdings (NASDAQ: SIRI), which only accounts for 1.1% of the conglomerate's total portfolio. Looking a little more closely, however, shows that while its stake is small as a percentage in the portfolio, Berkshire still owns a huge chunk of the company itself: 37%.
The stock price has been on a good run in 2026, climbing nearly 50% as of this writing. But going back a little further, it's also lost 50% over the past five years. It's dealing with subscriber slowdown and increased competition, which will continue to be difficult to navigate.
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That said, SiriusXM announced a deal with Alphabet that was easy to overlook but could be a meaningful long-term driver of revenue growth for the satellite radio company.
Image source: Getty Images.
SiriusXM announced a partnership with YouTube (owned by Alphabet) in April, making it the exclusive advertising representative of YouTube's U.S. audio advertising inventory. In addition to its video content, YouTube offers podcasts, talk shows, and music channels, which are all ripe for advertising opportunities. The ad process will be handled by SiriusXM Media and the platform AdsWizz, which SiriusXM owns.
Through the deal, which is supposed to kick off in the fall, SiriusXM can generate revenue by handling the ad process. But it could also be a cross-selling boost for the company, as advertisers may want to run ads on SiriusXM-run stations in addition to YouTube to increase an ad campaign's exposure.
Despite all the worry about how artificial intelligence is changing the search engine landscape, Alphabet is still generating hundreds of billions of dollars in ad revenue. That's because in terms of reach, advertisers still know Alphabet's search engine, Google, is a premier destination for looking something up online.
SiriusXM can operate in a similar capacity for advertisers. Instead of connecting advertisers to search engine users, SiriusXM connects advertisers with listeners through its extensive reach in the audio entertainment space. But that's more of an operational comparison than an example of what's possible in terms of revenue. In 2025, Alphabet generated $294.6 billion in just ad revenue, while SiriusXM's 2025 full-year revenue totaled $8.5 billion. SiriusXM will never haul in anywhere near what Alphabet makes in advertising.
That said, while it's difficult to put a dollar figure on what managing audio ads for other platforms could generate, the process can still become a meaningful revenue driver for SiriusXM.
The global podcast advertising market alone is expected to grow from $28.5 billion in 2026 to $38.5 billion by 2030, according to Grand View Research. And its current advertising revenue is showing steady progress; for the first six months of 2026, SiriusXM's total advertising revenue reached $861 million, a 4.2% increase from the first six months of 2025.
While it won't ever become an advertising powerhouse like Alphabet, handling the audio ad process for other platforms could become a new revenue growth engine for SiriusXM. And over the long term, that could continue to ignite investor enthusiasm, helping to extend the stock price's nearly 50% climb over the last year and reversing its 50% loss over the last five years.
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Jack Delaney has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Alphabet and Berkshire Hathaway. The Motley Fool has a disclosure policy.