On October 23, 2013, US Customs and Border Protection (CBP) published in the Federal Register a general notice advising the public of the quarterly Internal Revenue Service interest rates used to calculate interest on overdue accounts (underpayments) and refunds (overpayments) of customs duties. For the calendar quarter beginning October 1, 2013, the interest rates for overpayments will be 2 percent for corporations and 3 percent for noncorporations, and the interest rate for underpayments will be 3 percent for both corporations and non-corporations.