Sven is Swedish, runs the data team at a company in Málaga and has been in the article 93 regime (the special regime for workers who move to Spain, known as the Beckham regime) since 2023. In 2024 he sold a listed fund he held with a Stockholm broker, at a gain of 25,000 euros. His gestoría (the local firm that handles his tax paperwork) included that gain in his Modelo 151, the annual return under the regime, for 2024, and Sven paid tax on it. In 2026, reviewing his returns with another adviser, he discovers that he should not have declared it.
Mistakes in the 151 have a peculiarity: the regime is different from ordinary IRPF (personal income tax), and anyone who does not know it well tends to go wrong by applying the rules of the general regime. Almost always against the taxpayer, but not always.
Sven's mistake and what it cost him
While the regime lasts, foreign-source income that is not employment income, such as gains on selling assets located outside Spain, is not taxed in Spain. The Swedish fund gain did not have to be in the 151. By including it, the gestoría applied the 2024 savings scale to it:
| Band of the gain | Rate | Tax |
|---|---|---|
| First 6,000 euros | 19% | 1,140 euros |
| From 6,000 euros to 25,000 euros | 21% | 3,990 euros |
| Total overpaid | 5,130 euros |
Sven paid 5,130 euros he did not owe. The sale carried no withholding in Sweden, so there was not even a double taxation deduction to soften the mistake. Which income goes in and which does not is in which income goes in Modelo 151.
How the overpayment is recovered
When a self-assessment works against the taxpayer, its rectification is requested. The deadline is four years from the end of the filing deadline. The 151 for 2024 was due on 30 June 2025, so Sven can request it until 30 June 2029.
- The rectification is prepared, explaining that the gain relates to an asset located outside Spain and that the regime excludes it.
- The documents are provided: the broker's statement showing the sale, proof of where the fund was held and the document proving the option for the regime.
- The tax authority reviews it and, if it upholds the request, refunds the 5,130 euros with late-payment interest from the date of payment.
The refund is neither automatic nor guaranteed: the Agencia Tributaria may ask for clarification or dispute the foreign character of the asset. But with clear documents, it is an ordinary rectification. If you suspect your 151s may have a similar mistake, the Beckham regime form asks you for what is needed to review them.
The other usual mistakes, in both directions
| Mistake | Direction | How it is corrected |
|---|---|---|
| Declaring foreign income that is not employment income | You paid too much | Rectification with refund and interest |
| Filing Modelo 100 instead of the 151 | You normally paid a different amount from what was due | File the 151 and have the 100 set aside |
| Leaving out employment income paid from abroad, such as RSUs from the parent company or a bonus from another subsidiary | You paid too little | Supplementary return with the recargo (the surcharge for filing late unprompted) if there has been no request |
| Applying 24% to Spanish dividends or gains instead of the savings scale | Depends on the amount | Rectification or supplementary return, as the result shows |
| Not applying the deduction for double taxation of employment income earned abroad, with its limit of 30% of the corresponding tax | You paid too much | Rectification |
A missing Swedish bonus: the mistake in Sven's favour
The opposite case also exists. Suppose Sven's gestoría had not included a bonus of 20,000 euros paid to him by the Swedish parent company in 2024. That bonus is employment income, taxed at 24% even if it is paid abroad, and 4,800 euros of tax would be missing. The correction is a supplementary return, with the recargo if it is filed before the Agencia Tributaria acts. At 1 October 2026 the delay exceeds twelve months: a 15% surcharge, 720 euros, which falls to 540 euros with the 25% reduction, plus late-payment interest from July 2026. The tax itself cannot be claimed from anyone, because it was owed; the surcharge and the interest can be, if the information was in the gestoría's hands.
The mistake that cannot be fixed with Hacienda: a late 149
There is a gestoría mistake far more serious than any of the above: letting the deadline for Modelo 149 pass. The option for the regime is exercised within six months of registering with the Seguridad Social (Spanish social security) and late filing is not allowed. If the gestoría had been instructed to do it and did not file it on time, the taxpayer is taxed under ordinary IRPF for the six years, with no possibility of correcting it with Hacienda (the Spanish tax authority).
The difference can be enormous. With a salary of 150,000 euros, the regime means a tax bill of 36,000 euros a year. With the general IRPF scale, without special deductions and depending on the region, the tax comes close to 55,000 euros or a little more. That is around 20,000 euros a year, which over six years exceeds 100,000 euros. It is an estimate: the real calculation depends on the region, the family situation and the other income.
That loss is not recovered from Hacienda, but it can be claimed from the professional if the instruction was clear. Here the proof is everything: the engagement letter including the option for the regime, the emails in which the deadline was discussed and the date of registration with the Seguridad Social. The requirements for the 149 are in the deadline and documents for the 149.
To claim against a gestoría, a bad result is not enough. You have to show that the engagement included that task, that you provided the information in time and that the mistake was the professional's. If Sven did not tell his gestoría that the fund was in Sweden, the mistake may be shared. Before claiming, gather the written trail.
The claim, in order
Before Hacienda, the person obliged is always the taxpayer: any penalty is imposed on him and any refund is made to him. The relationship with the gestoría is a contract for services, and whatever the gestoría is liable for is claimed through the civil courts. The sensible order is to correct things first with Hacienda, find out how much is recovered and how much is not, and only then claim what has not been recovered.
In Sven's case, if the rectification succeeds, he recovers the 5,130 euros with interest and what can be claimed from the gestoría is limited, at most, to the fees for the rectification. In the case of the lost 149, what can be claimed is the difference in tax over six years, and there it does make sense to ask the professional to notify their professional liability insurer. Personal actions become time-barred after five years under article 1964 of the Código Civil (the Spanish Civil Code), a period it is wise not to run close to.
Meanwhile, Sven must not stop filing the 151 for 2025 or the following years because the 2024 one is under review: each tax year has its own deadline, and a rectification in progress does not suspend it. What does make sense is for the new adviser to prepare the next one on the corrected basis, so as not to repeat the same mistake and have to rectify again.
Sven has learned something else: the 151 is not an income tax return with a different number. Whoever prepares it has to know the regime, know which income stays out and ask, every year, where each asset that has been sold was held.
What people ask us when an adviser has got Modelo 151 wrong
If the mistake was my adviser's, am I still liable?
Before Hacienda, yes: in Modelo 151 the taxpayer is you, and the debt is claimed from you. What you can do is argue that there was no fault, which is what can bring down the penalty, not the debt, and, on a completely different level, claim against the professional or their insurer. They are two separate things and they follow separate routes.
Does the 24% apply to everything I earn?
No. It applies to employment income up to 600,000 euros; above that, the rate goes up. And capital gains and investment income follow their own scale.