“ Warren Buffett's Berkshire Hathaway (NYSE:BRK.B) has raised its stake in Mitsui & Co. (OTCPK:MITSY) to become a major shareholder, doubling down its bet on Japanese trading houses.

Berkshire (NYSE:BRK.B) now holds 10% or more of voting rights in Mitsui (OTCPK:MITSY), the Japanese firm disclosed on Monday, adding that the U.S. investment giant may expand its stake in the future.

Buffett first started investing in Japan's top five trading houses (called sogo shosha) - Itochu, Marubeni, Mitsubishi, Mitsui and Sumitomo - back in 2019.

Berkshire (NYSE:BRK.B) initially planned to maintain its stakes below 10% in each Japanese company. The firms agreed to "moderately relax the ceiling" as Berkshire approached this limit, Buffett wrote in his annual shareholder letter from February.

"Over time, you will likely see Berkshire's ownership of all five increase somewhat," according to the letter.“