The Tennessee Valley Authority amended a credit agreement that allows the federal utility to access up to $1 billion in either loans or letters of credit, according to a June 18 filing.

The agreement is set to expire June 13, 2023, unless extended. The interest rate will be based on market factors and the rating of TVA's senior unsecured long-term debt. The utility is required to pay an unused facility fee against which it has not borrowed or committed under letters of credit.

Royal Bank of Canada serves as administrative agent, letter of credit issuer and a lender. Other lenders include Barclays Bank PLC, BNP Paribas, Branch Banking and Trust Co., Mizuho Bank Ltd., Regions Bank, SunTrust Bank, and Wells Fargo Bank NA. RBC Capital Markets serves as lead arranger and book runner.