Warren Buffett’s Berkshire Hathaway Inc. bought stakes in five of Japan’s biggest trading companies, adding to the billionaire investor’s wager on the commodities sector and marking one of his largest-ever forays into Asia’s second-largest economy.

Berkshire acquired the stakes of about 5 percent in Itochu Corp., Marubeni Corp., Mitsubishi Corp., Mitsui & Co. and Sumitomo Corp. over the past 12 months, the U.S. conglomerate said in a statement. The investments were valued at more than $6 billion combined after shares of all five companies jumped at least 5 percent in Tokyo trading on Monday.

While Buffett has stayed relatively cautious with his record cash hoard since COVID-19 rippled through the global economy, Berkshire has been adding to its commodities exposure with deals including a $4 billion agreement to purchase most of Dominion Energy Inc.’s natural gas pipeline and storage assets in July.