Section 4-A-506. Rate of Interest

(1)  If,  under  this  Article,  a  receiving  bank  is obliged to pay
  interest with respect to a payment order issued to the bank, the  amount
  payable  may  be determined (i) by agreement of the sender and receiving
  bank, or (ii) by a funds-transfer system rule if the  payment  order  is
  transmitted through a funds-transfer system.
    (2)  If  the  amount  of interest is not determined by an agreement or
  rule  as  stated  in  subsection  (l),  the  amount  is  calculated   by
  multiplying  the  applicable  Federal  Funds rate by the amount on which
  interest is payable, and then multiplying the product by the  number  of
  days for which interest is payable. The applicable Federal Funds rate is
  the  average of the Federal Funds rates published by the Federal Reserve
  Bank of New York for each of the days  for  which  interest  is  payable
  divided  by 360. The Federal Funds rate for any day on which a published
  rate is not available is the same as the published  rate  for  the  next
  preceding  day  for which there is a published rate. If a receiving bank
  that accepted a payment order is  required  to  refund  payment  to  the
  sender  of  the  order because the funds transfer was not completed, but
  the failure to complete was not due  to  any  fault  by  the  bank,  the
  interest  payable  is  reduced  by  a  percentage  equal  to the reserve
  requirement on deposits of the receiving bank.