Prime Minister Fumio Kishida’s announcement that he will step down has unsettled stocks already hit hard by a surprise rate increase by the Bank of Japan late last month.

“Political uncertainty isn’t good at all,” Shoki Omori, chief desk strategist at Mizuho Securities, said following the news.

The announcement also came as the country remains under a megaquake alert and a tropical storm lurks offshore, adding to the general sense of unease.