RSUs in Spain. Neither the Spanish income tax act nor its regulations mention RSUs. What exists are rules on payment in kind and on irregular income, applied by analogy, plus a body of tax office rulings built one plan at a time. That is why the same grant is taxed differently depending on what you signed: when the units vest, what happens if you leave first, whether they settle in shares or in cash, and how much of the vesting period you spent here.
Oliver Brandt, a German, moved to Barcelona in 2023 and works remotely for a Californian cybersecurity company with a subsidiary in Madrid. His grant letter says "Incentive Stock Options", and a colleague in Texas has told him that ISOs "don't pay tax on exercise". Oliver has 5,000 options at 6 USD and the share is worth 30 USD today. He wants to know whether that advantage travels with him to Spain. The answer is that the ISO label has no counterpart in Spanish law: for Spanish income tax (IRPF), an ISO and an NSO are the same thing, a purchase option granted by reason of employment.
A classification born and buried in the US Code
The distinction between Incentive Stock Options and Non-qualified Stock Options is drawn by US federal tax rules. It determines how that system treats exercise and sale, and which holding or amount requirements the plan must meet. We do not explain any of that: how an ISO is taxed in the United States, whether there is alternative minimum tax or what happens on an early sale, is for a US adviser to confirm. If you are a US citizen, that conversation is essential; if you are not, it will probably only affect you indirectly, through what the company reports.
What we can say is what Spanish income tax does. Law 35/2006, the Spanish Income Tax Act, contains no equivalent category. Article 17.1 taxes as employment income any benefit deriving from the employment relationship, "whatever its name or nature". An option by another name is still, in the eyes of Spanish law, a benefit obtained by working.
One calculation for both acronyms
If Oliver exercises his 5,000 options today, the income in Spain is calculated in the same way whether they are ISOs or NSOs. For the purposes of the example, we take an assumed rate of 0.91 € to the dollar:
- Market value of the shares received: 5,000 × 30 USD = 150,000 USD.
- Price he pays: 5,000 × 6 USD = 30,000 USD.
- Spread: 120,000 USD.
- In euros, at the day's rate: 120,000 × 0.91 = 109,200 €.
Those 109,200 € are employment income in kind for the year of exercise. They are valued at normal market value, under article 43.1, and allocated when they become due, under article 14.1.a). The plan's acronym does not alter any of the four steps.
| Question | ISO | NSO |
|---|---|---|
| Is there income on grant? | No, if non-transferable | No, if non-transferable |
| When does the income arise in Spain? | On exercise | On exercise |
| What is taxed? | Difference between market value and price | Difference between market value and price |
| In which base? | General, as employment | General, as employment |
| And the later sale? | Capital gain | Capital gain |
The detail of each moment is in when my stock options are taxed.
What does change: the contract you signed
The fact that Spanish tax is neutral does not mean the ISO has no consequences for you in Spain. It does, but they come from the document, not from the law. ISO plans usually contain clauses designed to make the employee meet the US requirements, and those clauses shape when and how you can act. The most common ones:
- Short exercise windows on leaving the company. Many plans limit the time to exercise after termination so as not to lose ISO status. We cover this in I am leaving the company.
- Annual limits above which the options become NSOs. For you, in Spain, the conversion makes no difference; your broker portal will show two kinds of option and you should not be alarmed.
- An obligation to tell the company about a sale of the shares if it happens before a certain period.
- Recommendations to hold the shares for a period in order to keep the US advantage.
None of them alters Spanish income tax. But the last one can cost you money if you follow it without thinking, as we see next.
The cost of holding once you have already paid
Suppose Oliver exercises in 2026 and, following his Texan colleague's advice, decides not to sell for a year so as to "respect the ISO period". In Spain he has generated 109,200 € of employment income in 2026, which he will declare in the 2027 filing campaign. If the share falls 40 % during that year:
- Value of his shares a year later: 150,000 USD × 0.60 = 90,000 USD.
- Assume a rate of 0.91 € to the dollar on the sale as well: 81,900 €.
- Acquisition value in Spain: price paid (30,000 × 0.91 = 27,300 €) plus the income already taxed (109,200 €): 136,500 €.
- Capital loss: 81,900 − 136,500 = −54,600 €.
Oliver will have been taxed on 109,200 € in the general base, at his marginal rate, and will have a loss of 54,600 € that goes to the savings base. Savings losses are offset against savings gains and, within limits, against other income in that base; they do not directly reduce the tax he paid on his employment income. This is the classic asymmetry of exercising and selling later, which we develop in exercise now or wait.
If you are not a US taxpayer, keeping the shares to meet a US holding period may bring you no advantage at all and may leave you exposed to a fall in value after you have paid the Spanish income tax on exercise. If you are a US citizen, the decision requires coordinating both advisers. We cannot guarantee that one exercise-and-sale strategy will turn out better than another.
The documents that set your case apart
To work on an ISO plan we ask, as well as the grant letter, for the Equity Incentive Plan itself, because that is where the clauses on post-termination exercise, conversion and notification sit. The guide to reading an equity incentive plan indicates which sections to look at first. It also helps to know whether the Spanish subsidiary recognises the option as its own remuneration cost, because that affects whether it should make a payment on account. You can send the documentation through the equity form.
A question that is worth asking instead
Rather than asking whether ISOs pay less in Spain, which they do not, it is better to ask two other things. First: when would I rather the exercise income fell, this year or next? That depends on your other income and on whether you could meet the requirements of the 30 % reduction. Second: do I have the cash to pay the income tax on the spread without selling? If the answer is no, a plan that pushes you to hold the shares is a plan that forces you to borrow or to sell anyway.
Nothing changes with Modelo 720, the Spanish return declaring assets held abroad, either: once exercised, the shares are foreign securities just like those coming from an NSO, and they count towards the securities block if you exceed the thresholds. We explain it in options and Modelo 720.
The Salama Tax page on stock options and RSUs brings together the pieces that a Spanish resident needs to have in order, whatever name their company gives to each type of option.