carryback
noun
(also carry-back); (carry back) uk/ˈkæriˌbæk/ us [ U ] ACCOUNTING, TAX
the practice of treating a company's present profit or loss as if it happened in an earlier period:
These charges can be deducted as if they were trading losses for the purpose of carry-back of losses.
[ C ] ACCOUNTING
an amount that is copied from a later column of numbers or a later accounting period to an earlier one
[ U ] TAX UK
a rule that allows an employee to count this year's payments into their pension fund as if they were made in the previous tax year:
Carry back gives an opportunity for immediate tax relief.