Beatriz has had an optician's shop in Murcia since September 2024, in premises a private individual rents to her for 1,300 € a month plus VAT. In September 2026, while checking the withholding certificate her gestoría (the accountancy firm) had sent the owner, she noticed that the monthly withholding was 298.87 €. She had read that it was 19 % of the rent, and 19 % of 1,300 is 247 €. The gestoría had calculated the withholding on the bill including VAT. Pulling on that thread, a second error came to light: the IBI (the municipal property tax) that the owner passes on to her each September, 480 €, had never been included in the base. Two years of Modelo 115 wrongly calculated, one error in each direction.
Beatriz wanted to know three things: how much each error was, whom it harmed and who had to fix it. The third question has an uncomfortable answer and it is best given from the start: as far as Hacienda (the Spanish tax authority) is concerned, fixing it falls to her, whoever did the work. What is shared out are the consequences, and there is quite a lot to sort out there.
Two errors that do not cancel each other out
| Item | What the gestoría calculated | The correct figure | Difference |
|---|---|---|---|
| Monthly withholding base | 1,573 € (rent with VAT) | 1,300 € (rent without VAT) | |
| Monthly withholding | 298.87 € | 247.00 € | 51.87 € too much |
| Excess withholding over 24 months | 1,244.88 € too much | ||
| IBI passed on (480 € a year) | No withholding | 91.20 € a year | 182.40 € too little over two years |
It might seem that one error covers the other, but it does not work like that. They are different periods, different items and, above all, different people harmed. The excess withholding harms the landlord, who for two years received less money each month. The shortfall is a debt Beatriz owes Hacienda. Each is put right by its own route.
The shortfall: the one corrected straight away
The IBI passed on is part of what is paid to the landlord for the lease, so it carries withholding. If it was paid in September 2024 and September 2025, the omitted withholding belongs to the third-quarter 115s of those two years. It is corrected with two supplementary returns (complementarias), before any request from the tax office, so that they carry the article 27 recargo, the surcharge for filing late unprompted, and not a penalty. Filing them on 5 October 2026:
- Third quarter of 2024, due on 20 October 2024: more than twelve months, 15 % on 91.20 € = 13.68 €, plus interest.
- Third quarter of 2025, due on 20 October 2025: eleven full months, 12 % = 10.94 €.
With the 25 % reduction for paying on time, a little under 19 € in total. It is the easy part, and it is best done before anything else. How a request would change this calculation is in recargo versus penalty.
The excess: first, ask the landlord
Here is what almost nobody tells you. The excess withholding is not money Beatriz has lost: she deducted it from the landlord and paid it to Hacienda in his name. The landlord, with the certificate in hand, deducted in his 2024 income tax return the amount certified for September to December, and will presumably deduct in his 2025 return the 3,586.44 € for the full year. If so, he has already recovered it in his return, as lower tax or a larger refund.
That is why the first step is not to rectify the 115s to claim a refund, but to ask the landlord what he declared. If he has already deducted the certified withholding, rectifying the 115 now to claim the excess would be claiming the same money twice. The sensible course is usually to leave the past as it is where it has already been offset, correct the calculation from the next rent payment and clarify in writing with the landlord the cash-flow difference he bore. If, on the other hand, the landlord had not deducted those amounts, the route would be different, and who claims the refund and how is decided with his returns in front of you.
If in your case the error goes in only one direction, or you do not know which, tell us in the self-employed form: with the contract, the rent bills and the 115s filed, the full picture can be put together.
How an error like this happens, and how to avoid it
Calculating on the total including VAT is the most frequent failure on the 115 because the rent bill is usually recorded at its total, and whoever prepares the return takes that figure without separating its parts. The same happens, the other way round, with items that come on separate bills, such as the IBI or a special levy from the community of owners (a derrama): because they are not on the monthly bill, they are left out of the base.
The way to avoid it is to have a single sheet with the structure of the bill, like the one at the end of this page, and to require that each 115 can be rebuilt from it. An annual review, when the certificate for the landlord arrives in January, is enough to spot any deviation: if the certified withholding is not 19 % of the annual rent without VAT plus the expenses passed on, something is wrong. Beatriz would have seen it in January 2025 if anyone had done that division.
And a point about the landlord: even though he recovered the excess in his return, for two years he received 51.87 € less each month. If he raises it, it is reasonable to acknowledge it and talk about it, because he was the one who advanced that money, even if Hacienda gave it back to him afterwards.
As far as Hacienda is concerned, the person liable is Beatriz. The 182.40 € of omitted withholding, the recargo and the interest are claimed from her, regardless of who did the calculation. The landlord has nothing to put right about the IBI: he will deduct what is certified to him as withheld.
As against the gestoría, what can be claimed, if there was negligence, is the cost that would not have existed had the work been done properly: the recargo, the interest and the cost of correcting. Not the omitted withholding, which was owed anyway. The route is civil: the services contract and, behind it, the professional's indemnity insurance. What decides everything is the evidence: the engagement letter (hoja de encargo), the bills the gestoría had and whether the IBI passed on appeared in them.
The corrections to the 115 have to carry through to the annual summary on Modelo 180 and to the certificate the landlord receives. If the 115 says one figure, the 180 another and the certificate a third, the cross-check the Agencia Tributaria makes between what you declare you withheld and what the landlord declares was withheld from him will end up generating questions for both of you.
The correct bill, from next month
Rent, 1,300 €; VAT, 273 €; withholding, 247 €; total to transfer, 1,326 €. In September, in addition, the IBI passed on of 480 €, with its VAT of 100.80 € and its withholding of 91.20 €. With those figures, the 115 for each ordinary quarter will be 741 €, and for the third, 832.20 €. Beatriz put it in writing on a sheet she shares with her new asesoría, so that anyone who looks at it can check it. The guide to both kinds of withholding is in Modelos 111 and 115.