Japan investors bought about ¥140 billion ($1 billion) of Credit Suisse Group’s bonds that were written off when the Swiss bank was suddenly sold last month, Finance Minister Shunichi Suzuki said.

It’s "regrettable” that the fallout from Credit Suisse’s woes affected investors in Japan, Suzuki said at a news briefing in Tokyo on Friday. Securities firms must make every effort to deal carefully with their customers, he added.

Investors around the globe are on the hook for losses on the 16 billion Swiss francs ($18 billion) in risky bonds, known as Additional Tier 1 notes, that were wiped out when the Swiss government brokered an emergency takeover of Credit Suisse by UBS Group.