A tax loss is not a balance. It is a stack of vintages, each carrying its own eligibility, and three separate rules decide whether any of it is still usable.

The cap. Loss relief cannot reduce taxable income by more than 75% of taxable income before any loss relief (CT Law Art. 37(2)). "Before any loss relief" is the part that gets misread: the cap is measured against line 70 of the report, Taxable income before loss relief, not against whatever is left after something else has been applied.

What never enters the register. There is no relief for losses incurred before Corporate Tax applied to you, and none for losses arising from activities the law exempts (Art. 37(3)). A loss carried in your accounts from before the regime is an accounting balance, not a tax asset, and putting it in the register overstates your shelter.

The ownership test. Carrying a loss forward requires continuous ownership of at least 50% by the same persons (Art. 39(1)). Where ownership changes by more than 50%, the loss survives only if the same or a similar business has continued.

The group transfer. A loss can be transferred between two taxable persons where both are juridical Resident Persons and there is at least 75% common ownership between them (Art. 38(1)).

The trap: two different 75% tests. The 75% in Art. 37(2) caps how much of one year's income a loss may shelter. The 75% in Art. 38(1) is an ownership test for moving a loss between companies. They share a number and nothing else. Keep them apart in your notes, because a file that muddles them will muddle them consistently.

The register is at Accounting → Configuration → UAE Tax Reports → Tax-loss Register, and what it feeds is line 80 of the Corporate Tax report, Less: Tax-loss relief (capped). The word "capped" printed on that line is Art. 37(2) doing its work in public.

Worked example. Two companies, the same taxable income before relief of AED 2,000,000, different loss stocks.

Case B holds more losses and still pays tax, because the cap bites before the stock runs out. That is the normal outcome for a company returning to profit after a bad run, and it is why a loss stock is not the same thing as a tax shield.

The failure mode is a register nobody re-tested after a share sale. The balance keeps displaying and the report keeps applying it, while Art. 39(1) has already removed the right to use it. Whenever ownership moves, re-test every vintage in the register and record the conclusion — including the same-or-similar-business question where the change exceeded 50%.