Warren Buffett ( Trades , Portfolio )'s Berkshire Hathaway ( NYSE:BRK.A ) ( NYSE:BRK.B ) just dropped over $560 million on stocks during the December market slump, taking advantage of bargain prices. Leading the spree was an $405 million investment in Occidental Petroleum ( NYSE:OXY )8.9 million new sharespushing Berkshire's stake in the energy titan past 28%. Despite Occidental's rough year with a 24% drop in 2024, Buffett's bullish move highlights its operational upgrades, like bumping margins to 57% and maintaining solid shareholder payouts. The market took note, with Occidental shares climbing nearly 3% in pre-market trading.

The spending didn't stop there. Berkshire also scooped up 5 million shares of Sirius XM ( NASDAQ:SIRI ) for $113 million and added 234,000 VeriSign ( NASDAQ:VRSN ) shares for $45 million. Sirius XM has been hammered, down 62% this year, but Berkshire now controls 35% of the satellite radio company, betting on a turnaround after Liberty Media's restructuring this fall. VeriSign, a steady performer in Berkshire's portfolio since 2013, had a quieter year, underperforming the tech sector, but its role as a domain registry powerhouse keeps it firmly in the fold.

For investors, this is classic Buffett: zigging when others zag. Berkshire's latest moves are a masterclass in finding value during market dips, doubling down on sectors with long-term potential. As always, Buffett's playbook is clearwhen the market panics, look for opportunity. And this week, he showed us exactly how it's done.

This article first appeared on GuruFocus .