Outsourcing accounting under the SII: what changes when the deadline is four days
Corpshore Spain editorial team · · 6 min read
In summary: Spain's Immediate Supply of Information system binds companies with turnover above six million euros, those in the VAT group regime, and those on the monthly refund register. Billing records are filed within four days, and delay is penalised at 0.5 percent of the invoice amount, with a quarterly minimum of 300 and a maximum of 6,000 euros.
When a Spanish company outsources its accounting, the detail that most shapes the service design is not invoice volume but the calendar. And since the Immediate Supply of Information system came into force, that calendar stopped being monthly.
This article explains what the system requires, of whom, and what you should demand in the contract with your provider if you are in scope.
What is the SII and who is in scope?
The Immediate Supply of Information is the VAT management system created by the Spanish Tax Agency for maintaining VAT registry books through its electronic office, by sending billing records almost immediately.
Companies with turnover above six million euros are in scope, as are those in the special VAT group regime and those registered on the monthly refund register. Outside those cases, joining is voluntary.
One compensation for those in scope: SII filers do not have to submit form 347 for third-party transactions or form 390, the annual VAT summary.
What is the real filing deadline?
Four days to send billing records through the Tax Agency's electronic office. It is not a monthly or quarterly deadline: it is a continuous rhythm.
That is the underlying change. An accounting process designed around a monthly close accumulates work and clears it in a block; a process under the SII has to work continuously, because the clock starts with every invoice.
For an outsourced team, this means that work cadence and absence cover stop being an operational detail and become a compliance requirement.
What is the penalty for non-compliance?
Delay in maintaining the registry books through the electronic office is penalised with a proportional fine of 0.5 percent of the amount of the invoice being registered, with a quarterly minimum of 300 euros and a maximum of 6,000.
The cap limits the damage in any one quarter, but the penalty is quarterly and systematic non-compliance accumulates. It is also worth remembering that the tax obligation sits with the company in scope, not with the provider executing the process.
What should you demand from an outsourced accounting provider?
First, a service commitment expressed in the deadline that matters. An agreement written around a monthly close is no use if your company is in SII scope: the indicator has to be filing time from receipt of the document.
Second, absence cover. A four-day process does not tolerate the person running it being on holiday without a trained replacement, and that is one of the real advantages of a team over a single internal person.
Third, traceability. You must be able to evidence when each document was received and when it was filed, because in a dispute that trail is your defence.
And fourth, clarity about who answers. The provider executes; the tax obligation remains yours. A contract suggesting otherwise is describing reality badly.
Does outsourcing make sense under the SII?
Frequently yes, and precisely because of the deadline. A continuous four-day process holds up worse with one internal person than with a team that has cover, and the administrative load the SII generates is exactly the kind of repetitive, deadline-bound work an outsourced team absorbs well.
The requirement is that the contract measures what the rules measure. If your agreement with the provider is still written around a monthly close, outsourcing is not solving the problem you actually have.
This article is general information, not legal advice. We work alongside your legal advisors, not in their place.