Asian markets slumped Thursday as uncertainty around Zurich-headquartered Credit Suisse — on the heels of the collapse of a pair of midsize U.S. lenders — fed fears of a banking crisis.

Japanese mega-banks, including Sumitomo Mitsui Financial Group and MUFG, ended the day down after Credit Suisse announced that it would borrow up to 50 billion Swiss francs ($54 billion) from the Swiss National Bank after a slump in shares triggered market anxiety.

In Tokyo, the 225-issue Nikkei average and the broader Topix index were both down on Thursday morning, before recovering slightly by midday. Hong Kong’s Hang Seng followed a similar path.