Corporation Tax Act 2009 section 1153

Amount of a loss which is "unrelieved"

Section 1153 defines how to calculate the amount of a UK property business loss or trading loss that remains "unrelieved" — that is, the portion of the loss that has not yet been used up through various forms of tax relief.

• The unrelieved amount is the original loss reduced by any relief already obtained, including same-period deductions from total profits, earlier-period carry-back relief, and any losses surrendered to group or consortium members.
• Losses brought forward from earlier periods and trading losses carried back from later periods are ignored when calculating the unrelieved amount.
• For insurance companies whose UK property business losses are treated as deemed BLAGAB management expenses, special rules apply: the unrelieved amount depends on whether and how much is carried forward as unrelieved expenses, capped at the amount of the property business loss itself.
• Where an insurance company is treated as carrying on more than one UK property business, the losses from those businesses are aggregated for the purposes of this calculation.