Japanese trading houses, including Mitsubishi and Marubeni, rallied on Tuesday after Berkshire Hathaway’s plans to increase holdings were seen as a stamp of approval for the undervalued sector.

Mitsubishi rose as much as 8.6%, while Marubeni added almost 8% in morning trade in Tokyo. Mitsui, Itochu and Sumitomo also had strong gains. The broader Topix index slid 0.4%.

Warren Buffett’s conglomerate said in 2020 that it had invested in Japan’s five largest trading houses. Berkshire originally agreed to keep its holdings at the companies below 10%, but the trading houses have agreed to relax the ceiling "moderately,” Buffett said in his annual investor letter dated Saturday.