The top five trading houses in Japan now have a 7.4% stake in Warren Buffett’s Berkshire Hathaway Inc (BRKa.N), and the billionaire investor hinted that there may be further investments in the nation.

In an interview with Nikkei, Buffett, 92, stated that he is “very proud” of the investments and will be meeting with the trading houses this week to discuss their deals and possibly lay the groundwork for joint deals.

Itochu Corp (8001.T), Marubeni Corp (8002.T), Mitsubishi Corp (8058.T), Mitsui & Co (8031.T), and Sumitomo Corp. are the trading houses (8053.T).

Following the Nikkei interview in Tokyo on Tuesday, its shares increased 2.1% to 4.6%.

Japanese trading houses known as “sogo shosha” deal in a wide variety of materials, produce and food, often acting as middlemen and providing logistical support.

They are also heavily involved in the real economy in areas such as commodities, shipping and steel.

The business model may have lured Buffett, who prefers to invest for the long term and avoid deals he says he doesn’t understand.

“These five companies are not just a cross-section of Japan, they’re a cross-section of the world,” Buffett told the Nikkei. “You really are that much like Berkshire.”

Buffett’s Omaha, Nebraska-based conglomerate owns dozens of companies, including BNSF railroad, Geico auto insurance, and consumer, energy, and industrial companies, as well as stocks like Apple Inc (AAPL.O) and Bank of America Corp (BAC. N).