Warren Buffett Spent More Than $350 Million to Buy These Stocks in the Past Week

Buffett's Berkshire Hathaway now owns roughly 30% of Liberty SiriusXM shares outstanding

Warren Buffett has been busy during a relatively quiet week, as he has been bulking up his stake on Liberty SiriusXM tracking stocks.

In Form 4 filings with the US. Securities and Exchange Commission over the past week, Buffett's investment vehicle, Berkshire Hathaway Inc. $(BRK.B)$ $(BRK.A)$, disclosed that it paid about $257.95 million to buy 8.9 million Liberty SiriusXM Series C stock $(LSXMK)$ at a weighted-average price of $29.06.

Berkshire also disclosed paying $110.32 million to buy 3.8 million shares of Liberty Sirius XM Series A stock $(LSXMA)$ at an average price of $29.

The Series A shares have voting rights, but the Series C shares don't.

In total, Berkshire bought 12.68 million shares for $368.3 million.

Buffett now owns about 30% of Liberty SiriusXM's outstanding shares.

The Series A shares have gained 3.3% this week through Thursday and the Series C shares have advanced 3.4%. In comparison, the S&P 500 index SPX has edged up 0.4% this week.

Liberty SiriusXM is basically a tracking stock of Sirius XM Holdings Inc. (SIRI), the subscription-based satellite-radio service.

Liberty SiriusXM's "business" is that it owns a little more than 80% of Sirius XM, and about $1.7 billion of Sirius XM's estimated net liabilities, which includes convertible debt. Therefore, it is seen as trading at a discount to Sirius XM shares.

In Berkshire's latest 13-F filing of its equity holdings, the company said it owned 40.2 million shares of Sirius XM as of Dec. 31. At the time, it was valued at $221.1 million.

Year to date, Sirius XM's stock has tumbled 29.1%, while Berkshire's Class B stock has rallied 17.9% and the S&P 500 has gained 10.2%.