If the agency (“gestoría”) or the tax adviser makes a mistake, what can I claim from them?

Question

José Manuel Alburquerque · Accepted Answer

Whatever their mistake has cost you. If it is a mistake involving the tax authorities, normally the penalty and the surcharges, the cost of putting it right and the tax advantage you lost, but not the tax you had to pay anyway. If it is another kind of mistake, such as a grant lost because the application was filed late or a procedure handled incorrectly, whatever you lost as a result and the cost of doing it again. You can claim against the agency or the adviser and, if they have liability insurance, also directly against their insurer. What you can claim The penalty and the surcharges you would not otherwise have incurred. For example, if a tax return was filed late without the tax authorities having asked for it, the surcharge is 1 % of the amount that had to be paid plus a further 1 % for each full month of delay. After twelve months, it is 15 % plus interest. The cost of correcting the mistake and of defending yourself, such as what you pay another adviser. The tax advantage you lost, for example an allowance or a more favourable regime that you can no longer opt into. The tax, only if the mistake made you pay more than you owed. Whether late-payment interest can be claimed is disputed, because in the meantime you had the money. Outside tax matters, whatever you have lost through a missed deadline or a badly handled procedure, such as a grant refused because the application was filed late or an entry in a register that has to be made again. You always have to prove that the loss was caused by the mistake. If the adviser got it wrong because you did not give them a piece of information or a document, they may escape liability, so keep the letter of engagement, the emails and whatever you handed over. Whom to claim against and how The agency or the adviser you engaged. You are the one answerable to the tax authorities even if the mistake is the agency's, so you will have to pay or appeal against whatever they demand. Notify the agency straight away and claim from it whatever it has cost you. Their insurer. In Catalonia, in principle, tax advisers registered as “gestores administrativos” with their professional association, as well as economists or lawyers who give advice in that capacity, must have liability insurance or an equivalent guarantee. An adviser without a degree or professional membership is generally under no such obligation, so ask them whether they have insurance and request the policy details in writing. If the contract limits their liability to the amount of their fees, that clause may not be valid. In 2026 the “Tribunal Supremo”, Spain's Supreme Court, confirmed that one such clause used by a law firm was void and the same reasoning may apply to tax advisers. Make your claim in writing, explaining the mistake and what it has cost you. Before suing, you must try to negotiate, as the law has required since 2025. Time limit The time limit for claiming against them is in principle five years, or ten in Catalonia if the engagement is governed by Catalan law. It normally runs from when you learn of the mistake and what it is costing you, for example from when you are notified of the penalty. Even so, do not wait, because liability insurance usually only covers claims made while the policy is in force. A written claim interrupts the time limit, which then starts again in full.