Form 8396 - Mortgage Interest Credit

Only if you received a qualified Mortgage Credit Certificate (MCC) from a state or local government entity or agency in accordance with a qualified mortgage credit certificate program are you eligible to claim the credit.

For each tax year, you must determine the amount of credit that you would have been allowed using your original MCC. To do this, multiply the interest that was scheduled to be paid on your original mortgage by the certificate rate on your original MCC. The result may limit your line 3 credit allowed when you have a reissued MCC, even if your new loan has a lower interest rate.

See Pub. 530, Tax Information for Homeowners, for more details.