Deferring Taxes in January: Which Spanish Tax Debts Can’t Be Deferred

Every year-end, the same scene plays out: a freelancer or small business owner reaches January with cash flow stretched thin, sits down to file the fourth-quarter returns and takes comfort in the thought that, if the amount due is a squeeze, they can always ask for a deferral. The problem is that part of those taxes, by legal design, cannot be deferred. With the last quarter of 2026 just around the corner, it’s worth getting this clear now rather than a few days before the deadline.

Which taxes can’t be deferred, and why

As a general rule, the General Tax Act (Ley General Tributaria) allows a taxpayer to request a deferral or instalment plan for a tax debt when their economic and financial situation makes it impossible to pay on time. But that same law expressly excludes several cases, and a number of them coincide with the returns you file every quarter.

The first is withholdings and payments on account. What you withhold from employees, professionals or landlords (Modelos 111 and 115, for example) isn’t your money: you’re holding it on deposit for the tax authorities, which is why the law doesn’t let you use it to finance yourself.

The second is output VAT. The VAT you charge on your invoices isn’t your own income either, but a tax you collect on behalf of the State. The law does provide an exception where you can show that those amounts were not actually collected, but it is an exception you have to prove, not an automatic right.

The third affects companies: instalment payments of Corporate Income Tax cannot be deferred either. By contrast, other debts, such as the annual amount due under a personal income tax return or the Corporate Income Tax return itself, can be the subject of a request, always subject to the requirements of the regulations and to the decision of the tax authorities. For other payments on account, such as the Modelo 130 for freelancers, the prudent course is to check case by case before taking anything for granted.

What this means for your business

The practical lesson is simple: the VAT and withholdings for a quarter need to be set aside before the due date arrives. These are the decisions worth making right now:

Keep that money separate. Open a dedicated account or sub-account and set aside output VAT and withholdings as you invoice and pay. If you mix those funds with your day-to-day money, it’s easy to spend them without noticing.

Review your outstanding receivables. If you’ve charged VAT on invoices you haven’t yet been paid for, you may find yourself remitting VAT that your customer hasn’t paid you. Review the age of your accounts receivable and chase payment in good time. In certain cases of uncollectible debts it is possible to adjust the taxable base, but it requires meeting strict formal requirements, so seek advice before acting.

Adjust your payment calendar. If you know the fourth quarter will be heavy, stagger investments and supplier payments so you reach January with some margin. And if you need liquidity, explore other routes (bank financing, negotiating terms with suppliers) rather than counting on a deferral that may be rejected.

File early. With the holidays in between, the January deadlines feel tighter than they look. Having your paperwork closed early avoids mistakes and lets you set up the direct debit without stress.

What happens if you can’t pay

Filing the self-assessment on time even if you can’t pay it is usually better than not filing at all: filing late carries its own surcharges and can lead to penalties. That said, a debt that isn’t paid during the voluntary payment period enters the enforcement period, with surcharges and late-payment interest that make the problem more expensive. If you request a deferral that is later rejected, the debt is still there and the clock doesn’t stop, so talk to your advisor before the deadline runs out, not after.

At Zythos Business, we work precisely so that these surprises don’t arrive in January. We track VAT, withholdings and instalment payments for each client every quarter, calculate in advance how much will need to be paid and let you know when it’s time to set money aside, so you can decide calmly and with the numbers in front of you. If you’d like to review how your business is heading into year-end, we’d be happy to help.