South Korea"s central bank on Thursday said it has agreed with the U.S. Federal Reserve to let a bilateral $60 billion currency swap deal expire on Dec. 31, 2021, as scheduled. The bilateral currency swap deal was first signed in mid-March last year to help stabilise the local currency market and prevent the coronavirus pandemic from causing a global economic rout. Reporting by Cynthia Kim; editing by Richard Pullin Our Standards: The Thomson Reuters Trust Principles.