0 the practice of treating a company's present profit or loss as if it happened in an earlier period: --
1 an amount that is copied from a later column of numbers or a later accounting period to an earlier one --
2 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.
The carryback period was extended for the business credit, along with the bonus depreciation.
Such changes could occur, e.g., because of carryback of deductions, losses, or credits in the foreign country, changes on examination of returns, etc.