Berkshire Hathaway, led by Warren Buffett, bought 8.9 million shares of Liberty SiriusXM (LSXMA) Class C stock for $29 million and 3.8 million shares of Class A stock for $110 million last week, according to a recent filing with the U.S. Securities and Exchange Commission (SEC).

A review of previous filings shows that Berkshire Hathaway has been increasing its stake in the company since 2024, making it one of the company's most active trades of the year.

Notably, Buffett's aggressive buying spree stands in stark contrast to the bearish sentiment in the market, with Sirius XM's stock price having been heavily shorted this year, down nearly 29% year-to-date.