Section 9--340. Effectiveness of Right of Recoupment or Set-off Against Deposit Account

(a) Exercise of recoupment or set-off. Except as otherwise provided in
  subsection (c), a bank with which a deposit account  is  maintained  may
  exercise any right of recoupment or set-off against a secured party that
  holds a security interest in the deposit account.
    (b) Recoupment or set-off not affected by security interest. Except as
  otherwise provided in subsection (c), the application of this article to
  a  security  interest  in  a  deposit account does not affect a right of
  recoupment or set-off of the secured  party  as  to  a  deposit  account
  maintained with the secured party.
    (c) When  set-off  ineffective.  The  exercise  by a bank of a set-off
  against a deposit account is ineffective against a  secured  party  that
  holds  a  security interest in the deposit account which is perfected by
  control under Section 9--104(a)(3), if the set-off is based on  a  claim
  against the debtor.