Establish the tax loss
Begin with the accounting result and a tax reconciliation. Non-deductible expenses, exempt income and capital allowances can make the tax loss different from the loss in the financial statements. Reconcile the opening balance to filed computations and assessments, identifying unresolved adjustments.
Section 13 contains both the carry-forward rule and restrictions. The current seven-year wording does not mean an undated spreadsheet balance can be claimed without checking origin and applicable commencement or transitional rules. Keep older losses identifiable rather than combining everything into one total.
Use a loss register
For each origin year record the computed loss, adjustments, amounts used in each later year, amounts surrendered where permitted, remaining balance and last eligible year. Attach the return and computation supporting each movement. Confirm that the same loss has not been used twice.
Illustration: an available loss of €40,000 is used against €25,000 of eligible later profit. The remaining €15,000 stays in that original loss-year row. Its expiry does not restart because part of it was used.
Review changes in the company
The law restricts relief in specified combinations of ownership change and substantial business change, and where an inactive or negligible business changes ownership before substantial revival. A purchase of a company with accumulated losses therefore needs a separate review.
Late submission of accounts can also affect acceptance of losses under section 13. Do not assume a dormant company has preserved every historical loss merely because it remains registered.
Keep group relief separate
Current-year group relief and carried-forward losses are different mechanisms. Check the group relationship, period and other statutory requirements before recording a surrender. Reconcile the claimant and surrendering company schedules so both report the same amount.
Use the confirmed loss balance in the provisional-tax forecast. If the business is inactive, review the dormant-company checklist before assuming there is no filing work.