Spain's tax agency is sending out its 'scare letters'

Spain's tax agency is stepping up the sending of letters to request documentation or clarify details from tax returns, and taxpayers usually have **10 business days** to respond. Ignoring them does not make them go away: an unanswered request can end in a fine.

The 2025/2026 income tax campaign ended almost four months ago, but the tax agency has not closed the file. In recent weeks, notifications asking taxpayers for additional information or demanding a response to a personal request have multiplied. The tax management platform **TaxDown** points out that it is in the last months of the year when this trickle of letters concentrates, especially close to the final deadline for income tax in its instalment payment modality.

The calendar is tightening. On **Thursday, November 5**, the second and final deadline for the instalment payment expires. If there is not enough balance in the account provided to the tax agency on that day, the debt moves to the enforcement period with its corresponding surcharge, and one of those letters will most likely end up arriving. Hence the practical advice: before that date, check that the bank account reported to the agency has funds.

## What a letter from the tax agency actually is

The popular name is scarier than the content. **Aitor Fernández**, tax advisor at TaxDown, sums it up like this: receiving a letter from the tax agency does not necessarily miccionan you have done something wrong. In many cases, the agency only wants to verify a piece of data or request a supporting document. The label of "scare letter" actually covers very different documents, and it is worth knowing which is which before panicking.

There are purely informative letters, which require no response even though they arrive by certified mail and it is advisable to confirm receipt. Others are formal requests: they arrive when the tax agency detects that the return does not match the data in its fiscal reports and must always be answered, because failing to do so opens the door to a fine. There are also assessment proposals, which attach a draft with the changes the agency considers necessary for the taxpayer to review.

At the most serious end are enforcement orders, which set dates for collecting a debt, and seizure notices, which communicate the seizure of an asset, part of a salary or current accounts. With the latter, the seizure is not lifted until payment is made, and if it is not paid, the tax agency can auction the assets to settle the debt. There are also procedural resolutions, requests for documentation for an inspection and penalty proceedings that officially confirm an infringement.

## The three mistakes that trigger the most letters

TaxDown identifies three areas of the tax return as the usual focal points of these notifications. The first is tax residency. The agency asks for proof especially when the taxpayer has spent long periods outside Spain. Anyone who spends more than **183 days a year** in Spain, or whose main centre of activities or economic interests is there, is considered a Spanish tax resident, and in those cases a tax residency certificate from the other country is usually requested.

The second is the allowance for dependent children. To apply it, children must be under **25 years old** (or have a disability), live with the taxpayer and have income not exceeding **8,000 euros a year**. Many taxpayers fail one of these requirements without realising it.

The third is the state deduction for nursery school expenses. The most common mistake is including amounts paid with the company's childcare vouchers, which are considered tax-exempt amounts and therefore cannot be deducted.

## Deadlines and surcharges: what it costs to look the other way

The experts' advice is unanimous on the basics: the one thing you should never do is put the letter in a drawer. Read it calmly, pay close attention to the response deadline, which is usually **10 business days**, and seek help from a specialist before responding if in doubt. The clock starts running from the notification, not from when you remember to open the envelope.

Penalties depend on when payment is made. If you pay before receiving an enforcement order, the surcharge is **5%** of the amount owed. If you pay after the enforcement order, the surcharge rises to **10% or 20%**, plus late-payment interest if you miss the deadline. For returns filed late, paying on your own initiative means a surcharge of **1%** plus an additional **1% for each full month of delay**; after **12 months**, a **15%** surcharge applies plus late-payment interest. If it is the tax agency that detects the return was never filed, there is no longer a surcharge but a penalty, which is usually considerably higher.

It is worth remembering that these figures are the ones used by TaxDown and that each case has its particularities. Faced with a specific notification, the prudent thing to do is consult a tax advisor before responding or paying.