Proxies for Japanese pension funds bought a record amount of overseas bonds last month, adding to signs of robust demand for foreign debt even as local yields climbed. Bank trust accounts bought a net ¥3.16 trillion ($19.7 billion) in May, preliminary figures from the Finance Ministry showed on Monday. That was the highest in data going back to 2005. “A large share of the flows likely went into the U.S.,” said Miki Den, a senior interest-rate strategist at SMBC Nikko Securities.