Elena Martos is a self-employed graphic designer in Granada. In October 2026, within a limited verification procedure on her 2024 income tax, she receives a proposed assessment: the Agencia Tributaria, the Spanish tax agency, does not accept part of her business expenses and proposes that she pay 4,600 € more in tax, plus interest. Of that 4,600 €, around 2,800 € comes from rejecting the expenses for her car, which she also uses at weekends; the other 1,800 € relates to invoices for software and a computer that the authorities regard as "not justified", although Elena has all of them. The letter gives her ten days to put forward arguments. Her question is the one many people ask: do I sign and forget about it, or do I fight?
In a limited verification there is nothing to sign
The idea of "signing" comes from inspections, where the procedure ends with a formal record that the taxpayer may sign by agreement, in conformity or in disagreement. In a limited verification procedure there are no such records. Article 138.3 of the Ley General Tributaria, Spain's General Tax Law, requires the authorities to send the proposal "so that the taxpayer may put forward whatever arguments suit his or her rights", and article 99.8 sets the length of that step: between ten and fifteen days.
Faced with the proposal, the real options are three:
- Do nothing. The period expires and the authorities issue the provisional assessment on the terms proposed.
- State that you will not be putting forward arguments. Article 96.2 of the Regulations on tax management and inspection (Royal Decree 1065/2007) allows you to say so before the deadline; the step is treated as completed and the procedure speeds up.
- Put forward arguments. In writing, with reasoning and documents, in whole or in part.
None of the three is a signature and none, on its own, compromises the possibility of appealing the assessment later.
Where the agreement that reduces the penalty is found
The proposed assessment is usually followed by penalty proceedings, which are handled separately (article 208.1). And the penalty allows two reductions that depend on what you do afterwards:
| Reduction | Percentage | What gives it | What loses it | Article |
|---|---|---|---|---|
| For agreement | 30 % | Not appealing the assessment | Appealing or claiming against the regularisation | 187.1.d and 188.1.b and 2.b |
| For prompt payment | 40 % on what remains | Paying the penalty within the voluntary period | Appealing the assessment or the penalty | 188.3 |
The decisive sentence is in article 187.1.d): in a limited verification procedure, "agreement shall be deemed to exist provided that the resulting assessment is not the subject of an appeal or an economic-administrative claim". Agreement is not given at the proposal stage, but by not appealing the assessment. That is why putting forward arguments against the proposal does not cost you the 30 % reduction: arguing is not appealing.
Arguments against the proposal do not affect the reductions. An appeal against the assessment does: it costs you the 30 % and the 40 %, and the penalty is charged in full if the appeal fails. That asymmetry is what decides the strategy.
Elena's strategy in two stages
Elena's case has two very different parts, and they are best dealt with separately.
First stage: argue where there is evidence. The invoices for the software and the computer exist. The authorities regard them as not justified, perhaps because they did not ask for them or because they were provided incomplete. Elena should put forward her arguments and provide them now. Article 96.4 of the Regulations prevents documents from being added after this step unless it is shown that it was impossible to provide them earlier. If the authorities accept them, the proposal comes down by 1,800 € at no cost at all.
Second stage: decide with the assessment in hand. The car is another matter. Article 22 of the IRPF Regulations (the Spanish personal income tax regulations) requires, with few exceptions, vehicles to be used exclusively for the business, and Elena admits private use. She can argue the point anyway, but the chances of success are low. The real decision comes when the assessment is issued: whether or not to appeal it.
How to work out whether appealing pays
Let us suppose that the arguments succeed on the invoices and the assessment is left at 2,800 € for the car. Let us also suppose that the penalty is classed as minor, at 50 %. The figures, without interest:
If she does not appeal:
- Tax: 2,800 €.
- Penalty: 2,800 × 50 % = 1,400 €.
- With the reduction for agreement: 1,400 × 0.70 = 980 €.
- With the reduction for prompt payment: 980 × 0.60 = 588 €.
- Total: 2,800 + 588 = 3,388 €.
If she appeals and loses:
- Tax: 2,800 €.
- Penalty without reductions: 1,400 €.
- Total: 4,200 €, plus the cost of the appeal.
If she appeals and wins: 0 €, less the cost of the appeal.
Appealing costs 812 € more if it goes badly and saves 3,388 € if it goes well. Leaving fees aside, the appeal makes sense when the probability of winning is above roughly 19 % (812 divided by 4,200). With a mixed-use car, many professionals would put the probability lower. The calculation is not a prediction: it is a way of making visible what is at risk.
Appealing only the penalty
There is a third route. Article 212.2 allows the penalty to be appealed "without losing the reduction for agreement" provided the regularisation is not challenged. The 40 % for prompt payment is lost, because article 188.3.b) requires that neither the assessment nor the penalty be appealed, but the 30 % is kept.
It makes sense when there is little to argue about the tax, but the conduct does not deserve a penalty: for example, if Elena had followed the view in a binding ruling or a reasonable interpretation of the rule (article 179.2.d). In addition, an appeal against the penalty automatically suspends its collection without any guarantee (article 212.3). The differences between the two sets of proceedings are covered in is the penalty appealed separately from the assessment?.
The penalty proceedings come later, with their own deadlines
The penalty is not part of the proposal. Article 209.2 allows the penalty proceedings to be started within the six months following notification of the assessment, and article 210 gives fifteen days to put forward arguments against the proposed penalty. The proceedings must end within six months of their start; if not, they lapse and no new ones can be opened (article 211.4). That is why Elena does not have to decide everything at once: first the tax, then the penalty, each with its own arguments.
What to check before deciding anything
- The date. If the procedure has dragged on, it may be close to lapsing; this is explained in what a limited verification procedure is. In that case, replying quickly may not be the best course.
- The calculations. Proposals contain arithmetical errors more often than people think, especially in the regional share of the tax and in how income from different bases is combined.
- The facts. A poorly reasoned proposal, one that does not explain why it rejects a specific expense, is an argument in itself.
- The other years. If the car was also deducted in 2025, the same view will come round. It may be better to correct that year on your own initiative.
You can send the proposal, what you replied earlier and the return for the year through the letter-from-Hacienda form. The first review covers the arithmetic and the deadlines; the second, the arguments.
The guide from proposal to assessment describes the whole step, and the one on the penalty and its reductions develops the calculation with other scenarios. Analysing proposals and preparing arguments is described on the Salama Tax page on letters from Hacienda, the Spanish tax office.