Support for mortgage interest (SMI) From 6 April 2018, Support for Mortgage Interest (SMI) will be paid as a loan - which must be repaid when the claimant dies or sells their home. Before this date, SMI was paid as a benefit, which claimants did not have to repay. The amount that a claimaint may have already received as a benefit does not need to be repaid. Manage Cookie Preferences