TOKYO (AP) — Billionaire investor Warren Buffett’s Berkshire Hathaway said Monday it has taken stakes of just over 5% in five major Japanese trading houses in what it says is a long-term investment.

Share prices of the five huge companies surged between 4% to 9.5% on Monday in Tokyo after the company announced the investment.

Berkshire Hathaway said that its subsidiary National Indemnity Co. planned to notify regulators of the purchases that had been made over the past year.

The companies are Itochu Corp., Marubeni Corp., Mitsubishi Corp., Mitsui & Co. and Sumitomo Corp.

It said it might increase the stakes to up to 9.9% in any of the companies. It described them as “passive investments,” noting that the company has held similar holdings in Coca-Cola, for 32 years; American Express, for 29 years and credit ratings agency Moody’s, for 20 years.

The powerful trading houses are some of Japan’s oldest and biggest companies and the anchors of vast industrial groups called keiretsu.

Although the Japanese economy has been growing slowly for most of the past two decades and has been in recession since late last year, major companies have invested on a global scale and are cash rich.

They are also viewed as relatively undervalued, with price to earnings ratios, in most cases, well below the average for markets in the U.S. and Japan.

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