Warren Buffett’s Berkshire Hathaway Inc. sold yen bonds at lower costs in its second Japan deal of the year as speculation mounts that the billionaire investor may put more money into the nation’s share market.

In a ¥122 billion ($810 million) offering of five tenors of notes ranging from three years to 35 years, the firm was able to reduce spreads compared with its previous sale. It priced three-year bonds at a premium of 59 basis points over swaps versus 75 basis points in April, at a time of heightened market volatility after the appointment of Kazuo Ueda as Bank of Japan governor and banking-sector troubles overseas.

Berkshire is one of the largest overseas issuers of yen debt, and 32 out of its past 40 bond deals have been in the Japanese currency. It’s also a keen investor in Japan’s equities: Buffett announced in June that he had increased his holdings of firms including Mitsubishi Corp. and Itochu Corp., which lifted sentiment for the country’s overall stock market and helped propel stocks to a 33-year high.

A Daiwa Securities Co. analyst wrote earlier this month that the veteran investor may be looking at Japanese banks, insurers and automakers as his next investment targets.