Warren Buffett's Berkshire Hathaway Inc (NYSE:BRK) announced Monday that it has increased its stakes in Japan's top five trading houses. This move is believed to have contributed to the robust momentum driving the nation's stock market to reach multiyear highs.

The company holds stakes in Itochu Corp. (OTCPK: ITOCF), Marubeni Corp. (OTCPK: MARUF), Mitsubishi Corp. (OTCPK: MSBHF), Mitsui & Co. Ltd (OTCPK: MITSY), and Sumitomo Corp. (OTCPK: SSUMF).

Berkshire said its stakes in these companies now average more than 8.5%. The Japanese companies' aggregate value considerably exceeds Berkshire-held public stocks in any other country outside of the U.S.

In 2020, Berkshire first bought stakes in Japan's trading houses.

"The tailwinds for Japanese equities continue to multiply," Reuters quoted Charu Chanana, market strategist at broker Saxo Markets in Singapore, as saying.

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"While it was previously hinted that Berkshire will increase its stake, the announcement has come somewhat sooner than expected and will further boost optimism on Japanese stocks," Chanana said.

Berkshire remains committed to maintaining its Japanese investments for the foreseeable future. With regard to pricing, the company said it is open to expanding its holdings in any of the five assets, with a maximum stake of 9.9%.

Earlier in April, Buffett traveled to Japan and met with the CEOs of each of the five companies.

According to regulatory filings from June 12, the trading firms' reports revealed Berkshire Hathaway's ownership percentages as follows: 7.4% of Itochu's stock, 8.3% of Marubeni and Mitsubishi's stock, 8.1% of Mitsui's stock and 8.2% of Sumitomo's stock, reports Reuters.

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