Form 347: Transactions with Third Parties and Why the Tax Agency Cross-Checks Your Data

Every February, many self-employed professionals and small businesses receive a notice or letter from the Tax Agency that opens the same way: “there is a discrepancy between the data declared by you and by your supplier/client on Form 347.” Behind that notice lies one of the most effective control mechanisms the Spanish Tax Agency has: the automatic cross-check of the annual return of transactions with third parties. Understanding how this form works, when you’re required to file it, and how to avoid mismatches is key to staying off the receiving end of unnecessary information requests.

What Form 347 is and who must file it

Form 347 is an annual informative return in which businesses and self-employed professionals report to the Tax Agency any transactions with a given client or supplier that together exceed a set amount over the calendar year. It isn’t a tax return in the sense of paying anything when you file it — it’s pure information the tax authorities use for cross-referencing. As a general rule, individuals and companies carrying out business or professional activities must file it whenever they have transactions exceeding the set threshold. Exclusions include, among others, those taxed under the simplified VAT regime for transactions covered by that regime, or those who haven’t exceeded the minimum amount with any third party during the year.

The €3,005.06 threshold: how it’s calculated

The figure that triggers the obligation to report a business relationship is €3,005.06 per year (VAT included) with the same client or supplier. It’s a cumulative amount: it doesn’t matter whether that figure was reached through a single invoice or twenty small invoices spread across the year — what matters is the total amount billed to (or received from) that particular person or entity during the year. For example, if over the course of the year you’ve issued four invoices of €900 each to the same client, the total comes to €3,600, and that relationship must be reported, even though each individual invoice falls well below the threshold. It’s also worth remembering that transactions are broken down by quarter within the form itself, and that certain transactions — such as those subject to withholding tax, commercial property leases, or cash payments over €6,000 — follow specific rules for how they’re counted or reported separately.

How to reconcile the form with clients and suppliers before filing

Most problems with Form 347 don’t stem from the form itself, but from the fact that the figures you report don’t match what the other party reports. Before filing, it’s worth reviewing your issued and received invoice records and grouping the amounts by each client’s or supplier’s tax ID, checking that every group exceeding the threshold is correctly identified. A good habit is to compare, whenever possible, the accumulated figures with your regular business partners ahead of the filing deadline — especially those you work with on an ongoing basis. You also need to be careful with timing: transactions are attributed to the year in which they accrue, which for VAT purposes usually matches the invoice date, but this can create discrepancies if one party records an expense or income in a different year than the other party does.

Common mismatches and how to avoid them

The most frequent mismatches arise from invoices recorded in different quarters by each party, errors in a third party’s tax ID, corrective invoices or credit notes that one of the two businesses forgets to include, or transactions that one party considers exempt or not subject to VAT — and therefore doesn’t report — while the other party does count them. Discrepancies are also common when deposits, down payments, or installment payments are booked at different times by each party. When the Tax Agency detects a difference between what both parties have reported, it doesn’t automatically assume fraud, but it will typically send a request asking for justification or a corrected return — a process that takes time and that can almost always be avoided by carefully reviewing the figures before the filing deadline.

At Zythos Business, we help self-employed professionals and small businesses precisely with details like these, which may seem minor but are exactly what generates unnecessary notices, letters, and headaches. We review cross-checks with clients and suppliers ahead of time, catch discrepancies before the Tax Agency does, and file every informative return with the rigor that sound bookkeeping demands — so our clients can focus on their business with the peace of mind that their tax obligations are fully up to date.