Tax Compliance: All Tax Obligations Met, No Surprises

Tax compliance in Spain refers to the systematic fulfilment of all periodic tax filing obligations imposed by the Spanish Tax Agency (Agencia Estatal de Administración Tributaria, AEAT) under the General Tax Act (Law 58/2003, LGT) and the regulations of each individual tax. A typical Spanish company faces over 50 annual obligations — including quarterly VAT (Form 303), corporate tax instalments (Form 202), payroll withholdings (Form 111), the annual corporate tax return (Form 200), and informative declarations (Forms 347, 349, 390) — with late-filing surcharges of 1% per month of delay (up to 12 months) and a fixed 15% surcharge thereafter, plus late-payment interest; companies with turnover exceeding EUR 6 million are additionally subject to the Immediate Information Supply system (SII, Royal Decree 596/2016) requiring VAT ledger data to be transmitted to the AEAT within four business days of each invoice.

Tax compliance in Spain requires systematic, proactive management: deadlines are immovable, penalties are automatic, and the AEAT’s increasingly sophisticated data-matching tools mean that errors — even unintentional ones — are easily detected.

Why Poorly Managed Tax Compliance Generates Automatic Penalties in Spain

A mid-sized Spanish company has over 50 annual tax obligations: monthly or quarterly VAT (Form 303), the annual VAT summary (390), payroll withholdings (111), rental withholdings (115), dividend and interest withholdings (123), corporate tax instalments (202), the annual corporate tax return (200), third-party transactions (347), intragroup operations (349), and additional informative declarations depending on the sector. A single missed deadline generates a surcharge of 5% to 20% plus late-payment interest, automatically and without the need for a penalty proceeding. And that is before considering AEAT enquiries, which arise from any discrepancy between filed returns — something that happens more frequently than expected when VAT, withholdings, and corporate tax are managed separately without a unified view.

Our Tax Calendar Management and Tax Obligation Process

Our team acts as an external tax department: we manage the company’s complete tax calendar with automated alerts for each deadline and a well-defined information flow between the client and our team that eliminates last-minute pressures. We prepare and file all returns with cross-referencing between them: we verify that Form 303 is consistent with Form 349, that payroll withholdings in Form 111 align with personnel costs in the corporate tax return, and that Form 347 does not generate discrepancies with accounting records. Where the company is subject to the SII, we manage invoice submission to the AEAT within four business days. For any enquiry or review, we respond directly to the AEAT without the client needing to be involved.

Regulatory Framework: LGT, SII, and Tax Deadlines in Spain

The Spanish tax calendar is governed by the General Tax Act (Law 58/2003) and the regulations of each individual tax. Late-filing surcharges are 1% per month of delay (up to twelve months) and 15% for periods beyond twelve months, plus late-payment interest. Penalties for minor infringements start at 50% of the unpaid quota. The SII — Immediate Information Supply — is mandatory for companies with turnover above EUR 6 million and requires submission of issued and received invoices within four business days. Limited review proceedings can be initiated by the AEAT within four years of the filing deadline for each return, extendable in cases of concealment.

Real Results in Tax Compliance: Zero Penalties and Zero Unmanaged AEAT Enquiries

• Zero penalties or surcharges for late filing: 100% of returns filed before the deadline.
• Full consistency across all returns: VAT, withholdings, and corporate tax cross-referenced before submission, not after receiving an enquiry.
• All AEAT enquiries managed without the management team needing to spend time on them.
• Annual compliance audit that identifies risks before the Administration detects them, with a voluntary disclosure proposal where appropriate.
• SII capability integrated with the client’s ERP for large companies, with automated submission and data quality control.

Tax compliance is far more than filing returns on time. The declarations must be consistent with each other: what is declared in the VAT Form 303 must align with the intra-EU Form 349, the third-party transactions Form 347, and the corporate tax return. The AEAT cross-references this information systematically, and any material discrepancy generates an enquiry that, if not managed correctly, can escalate into a limited review. Our periodic compliance audits identify these inconsistencies before the Administration detects them.

Management of the Immediate Information Supply (SII) is one of the greatest compliance challenges for large companies. Submitting issued and received invoices to the AEAT within four business days requires highly tuned internal processes and constant data quality review. We implement and supervise SII systems, integrating information directly with the client’s ERP to minimise the operational burden and eliminate inconsistency risk. This integration complements our accounting service where we also manage the client’s bookkeeping.

AEAT representation is perhaps the most valued element of our compliance service. An information request can appear routine, but an inadequate response can turn a limited review into a full inspection. Our advisers know in detail the criteria the AEAT applies, understand what information must be provided and how to present it most favourably. We act as a shield between the client and the Administration, managing every communication with precision and maximising the defensive position in every procedure.

Proactive tax calendar planning at the start of the year is the preventive element that brings the most peace of mind to management teams. We know exactly which return must be filed, on which date, with which data, and what information flow is needed to prepare it. This forward-looking control eliminates last-minute pressures, allows any problem to be detected with sufficient time, and keeps the finance team focused on higher-value activities.