Warren Buffett Goes On Stock Buying Spree During Market Downturn: Report

Billionaire Warren Buffett's investment firm went on a buying spree this week, sweeping up shares of Occidental Petroleum, Sirius XM Holdings and VeriSign, according to filings with the Securities and Exchange Commission.

Berkshire Hathaway's biggest acquisition was about $405 million of Occidental Petroleum, or about 8.9 million shares of the global energy giant, Barrons reported.

The purchase gives the Nebraska-based conglomerate about a 28% stake in Occidental, whose shares hit a 52-week low on Thursday, the report said.

The 94-year-old "Oracle of Omaha" also scooped up about 5 million shares of Sirius XM for about $113 million, once again taking advantage of a drop in the company's stock price.

The satellite radio company's stock is down more than 60% this year.

Berkshire now holds about 117.5 million shares, meaning it has a 35% stake worth about $2.4 billion, Barron's reported.

That purchase is believed to have been managed by Berkshire investment manager Ted Weschler.

Berkshire also bought about 234,000 shares of VeriSign for about $45 million.

It holds 13 million shares of the Virginia-based tech company.