Interest income from Spain: how taxation works for Dutch investors

Interest income from Spain is assessed in two countries for a Dutch investor. Spain looks at the source of the interest, while the Netherlands looks at your place of residence. For interest paid by a Spanish company to a resident of another EU member state, Spanish law generally provides an exemption, provided you can prove your place of residence. In the Netherlands, a privately provided loan falls under Box 3, where it is not the interest received that is taxed, but a deemed return on the value of the claim. This article explains how these two sides interact, where things go wrong in practice, and what you should arrange in advance.

Why interest income from Spain is treated differently

Anyone participating in a Spanish real estate project for a fixed fee is, from a tax perspective, a creditor rather than a property owner. That distinction determines everything that follows. With direct ownership of a property, Spain, as the source country, has the primary right to tax rental income and capital gains, as detailed in the article on Spanish real estate and Box 3. In the case of a loan, the income is considered interest, and different rules apply to interest under both Spanish law and the tax treaty. The structure of your participation is therefore the first question, not the last. How the project structure itself works is explained in the article on investing via a Spanish S.L..

The Spanish side: withholding tax and the EU exemption

Spain taxes income of non-residents via the non-resident income tax, the IRNR. For interest, three elements are important: the exemption for EU residents, the withholding if that exemption is not applied, and the limit set by the tax treaty. Which situation applies to you depends on your place of residence and how you demonstrate it. Whether you have a permanent establishment in Spain also plays a role. For a private investor participating from the Netherlands, this is almost never the case.

The exemption for EU residents

The Spanish IRNR law exempts interest earned by residents of another EU member state without a permanent establishment in Spain. This exemption is not automatic. The Spanish company paying the interest must be able to substantiate that you live in the Netherlands. For this, you need a certificate of tax residence, which you can request from the Dutch Tax and Customs Administration (Belastingdienst). Without that document, the payer generally assumes that the exemption does not apply.

Withholding without a certificate of residence

If the certificate is missing, the Spanish payer will generally withhold 19 percent withholding tax on the gross interest. That amount is not lost, but reclaiming it takes time. To do so, you must submit a refund request in Spain via the non-resident tax return form, with the certificate of residence attached. Expect a turnaround time of months, not weeks. Those who arrange this in advance prevent a portion of their return from being held by the Spanish tax authorities for an extended period.

What the tax treaty adds

In addition to Spanish law, the 1971 tax treaty between the Netherlands and Spain applies. That treaty limits the Spanish withholding tax on interest to a maximum of 10 percent, which is relevant in situations where the EU exemption is not applied. The Netherlands and Spain have negotiated a new treaty. As long as that new treaty has not entered into force, the existing agreements remain in effect. Follow the status of affairs through your advisor, as the effective date determines which regime applies during your term.

The Dutch side: Box 3 for a privately provided loan

In the Netherlands, a claim on a Spanish company falls into Box 3, under the category of "other assets." It is not the interest you receive that is taxed, but a deemed return on the value of the claim as of January 1st. For 2026, that deemed return on other assets is 6.00 percent, taxed at 36 percent. The tax-free allowance is 59,357 euros per person. Whether you receive 9 percent interest or no interest in a given year makes no difference to this calculation in principle.

Counter-evidence and actual return

Through the counter-evidence provision, you can demonstrate that your actual return was lower than the deemed return. For a loan with a fixed fee above the deemed percentage, this usually yields nothing, as the actual return is higher. For a project that experiences delays and pays no interest in a given year, the situation may be different. In addition, the government is working on a system that taxes based on actual return, intended for 2028. How that will work for an ongoing position is a question for your own tax advisor.

Prevention is more effective than offsetting

If Spain does withhold tax, the question arises as to whether the Netherlands will offset it. The treaty includes a provision to prevent double taxation, but the application in Box 3 is not straightforward because the Netherlands taxes a notional return while Spain taxes an actual payment. Whether and to what extent offsetting is possible depends on your total tax return. For this reason, it is more effective to prevent Spanish withholding than to offset it afterward. The certificate of residence is the most important instrument for this.

Interest via a holding company: corporate income tax instead of Box 3

If you provide the loan from a private limited company (B.V.), the Dutch tax implications change entirely. The interest is then considered taxable profit for corporate income tax purposes, with a rate of 19 percent on the first 200,000 euros of profit and 25.8 percent on any amount above that. The tax is levied on the interest actually accrued, not on a deemed percentage. The Spanish side remains essentially the same, as a Dutch company can also invoke the EU exemption once its tax residency has been proven. You can read about the considerations involved in participating through a holding company in the article on real estate through your holding company.

A calculation example with a downside scenario

Suppose you privately provide 250,000 euros to a Spanish project company, at a fixed fee of an indicative 9 percent per year and a term of 24 months. The example illustrates the mechanism and is not a forecast. Past results are no guarantee for the future. We assume an investor without a tax partner, without other Box 3 assets, and using the 2026 figures. In reality, your total assets count and the outcome will be different.

Base scenario, with certificate of tax residence

• Gross annual interest: 22,500 euros
• Spanish withholding tax: 0 euros
• Box 3 tax base after tax-free allowance: 190,643 euros
• Deemed return of 6.00 percent: 11,439 euros
• Box 3 tax at 36 percent: approximately 4,118 euros
• Remaining annual amount: approximately 18,382 euros

Alternative scenario, without certificate and with delays

• Spanish withholding tax of 19 percent: 4,275 euros per year, refundable after several months
• Box 3 tax remains approximately 4,118 euros, regardless of the withholding
• Available in the first year until the refund: approximately 14,107 euros
• If the project is delayed by six months and interest payments are suspended during that period, the Box 3 tax on the receivable continues to accrue regardless

The difference between the two scenarios lies not in the tax rate, but in timing and administration. In the base scenario, the position is clear and predictable. In the alternative scenario, over 4,000 euros per year is temporarily tied up in Spain, while the Dutch tax obligation continues unabated. What happens to your position in the event of a delay is described in the article on <a href="#">exit scenarios for a Spanish renovation project</a>. This is also why it is important to define interest provisions for delays in the agreement beforehand.

Common mistakes

Most problems with interest income from Spain do not arise from complex legislation, but from poor sequencing and forgetfulness. A document that arrives three weeks late can cost you months in the refund process. A receivable that is not included in your tax return leads to a correction plus interest. These are the most common mistakes in practice.

• Applying for the certificate of tax residency only after the first interest payment has been made
• Assuming that the interest received should be declared in Box 1, while a privately provided loan falls under Box 3
• Failing to include the receivable in the tax return as of January 1st, or reporting it at an incorrect value
• Forgetting that Spanish parties generally only accept a certificate for one year, meaning a new one is required for multi-year terms
• Routing interest through a holding company without ensuring that the agreement and administration are set up accordingly

Frequently asked questions

Below are the most frequently asked questions regarding the tax treatment of interest from a Spanish project.

Do I need to file a tax return in Spain for interest from a Spanish project?

When applying the EU exemption based on a valid certificate of tax residence, you generally do not have a Spanish tax filing obligation for that interest. The paying company makes its own filings with the Spanish tax authorities. If tax has been withheld, a tax return is required to claim the refund. Have this assessed for your specific situation.

How do I request a certificate of tax residence?

You request the certificate from the Dutch Tax and Customs Administration (Belastingdienst), specifying the country for which you need it. Spanish parties usually request a certificate that explicitly refers to the tax treaty. Ask the paying company in advance which format they accept. Allow for a processing time of several weeks.

Is a claim with mortgage security treated differently in Box 3?

No. Your position remains a claim under "other assets," and the existence of security does not change the tax category. The security does, however, affect your position if the project underperforms. You can read how to verify what has actually been registered in the article on <a href="#">mortgage security in Spain</a>.

Is profit sharing fiscally the same as interest?

No. With profit sharing, you do not receive a periodic payment but a share in the results after sale, and the Spanish and Dutch tax treatments follow a different path. Which form of participation yields which return profile is explained in the article on <a href="#">returns on Spanish real estate</a>. The tax consequences of that choice vary per person. Discuss them with your advisor before you commit.

Do I need an NIE to receive interest from Spain?

Not necessarily for receiving interest alone, but as soon as notarial acts are required, such as the registration of a mortgage right, you need a Spanish tax identification number (NIE). This can be done without you having to travel to Spain yourself. You can read how that works in the article on <a href="#">powers of attorney in Spain</a>. Arrange it in good time, as the application takes several weeks.

Next steps

Interest income from Spain is straightforward from a tax perspective once the sequence is correct. Request your certificate of tax residency before the first interest payment is made, report the receivable correctly in your tax return, and determine in advance whether you are participating privately or through a company. Present your specific situation to a tax advisor with knowledge of both the Dutch and Spanish systems. Would you like to know what the compensation structure looks like in a specific project proposal? Schedule a personal appointment.

This article is general in nature and does not constitute legal or tax advice.