SII (Suministro Inmediato de Información)

SII is Spain's scheme for keeping VAT books electronically and reporting them to the tax authority almost immediately.

Definition

SII (Suministro Inmediato de Información, "Immediate Supply of Information") is an electronic reporting mechanism run by the Spanish tax authority (AEAT). Instead of filing VAT books periodically, the taxpayer transmits the details of issued and received invoices through the AEAT web services.

SII does not transmit the invoice itself but the VAT ledger data (sales and purchase ledgers, capital goods, intra-Community transactions).

Who is affected

SII is mandatory for certain categories of taxpayer, notably large enterprises above a defined turnover threshold, VAT groups, and businesses on the monthly VAT refund register (REDEME).

Other businesses may opt in voluntarily.

How it works

Records are sent to the AEAT within a short window — generally four business days from issuing the invoice (weekends and national public holidays are excluded from the count).

• Data is exchanged in XML via the AEAT's secure web services.
• The AEAT returns an acknowledgement marking each record as accepted, accepted with errors or rejected.
• Adopting SII removes the obligation to file several annual summary returns.

Good to know

SII is a VAT reporting scheme, not a clearance e-invoicing system: it neither authorises nor validates the invoice before it is issued. It coexists with the gradual rollout of mandatory B2B e-invoicing in Spain (the Crea y Crece law and the Veri*FACTU system).