Electronic Credit Notes: Tax Authority Sets the Bar for Digital Proof of Customer Acknowledgement

Summary

• 📋 Binding Ruling issued 27 April 2026 (Process no. 29882): The Portuguese Tax Authority (Autoridade Tributária – AT) confirmed that electronic means — including digital invoicing platforms — are admissible as valid evidence of customer acknowledgement for VAT credit note adjustments under Article 78 of the Portuguese VAT Code, provided they guarantee traceability, unequivocal proof of awareness, correct document identification, and proper digital archiving. [nominaurea.pt], [linkedin.com]
• ⚠️ Case rejected on documentary shortcomings: Despite accepting the principle of electronic evidence, the AT denied the VAT adjustment in the specific case analysed because (i) emails and tracking files incorrectly labelled credit notes as “invoices,” (ii) evidence did not demonstrate individual and unequivocal acknowledgement of each credit note, and (iii) electronic records were not adequately archived within the company’s accounting system. [nominaurea.pt]
• 🏢 Practical impact for multinationals: Businesses relying on automated e-invoicing, SaaS platforms, or high-volume VAT adjustment processes must now ensure their systems produce robust, auditable digital trails — or risk tax corrections, additional assessments, compensatory interest, and audit contingencies. [nominaurea.pt]

Article

1. Background: Credit Notes and VAT Recovery in Portugal

Under Article 78 of the Portuguese VAT Code (Código do IVA), whenever a taxable person adjusts VAT downwards — for example, to correct invoiced amounts, grant retrospective discounts, or cancel transactions — the supplier may only recover the VAT previously remitted to the State if there is proof that the customer became aware of the adjustment. [nominaurea.pt]

Traditionally, this proof took the form of physical documents signed by the customer, such as:

• A signed copy of the credit note
• A confirmation letter
• A return receipt or formal written communication [nominaurea.pt]

However, the widespread adoption of electronic invoicing platforms has raised a fundamental question: can digital evidence replace these traditional paper-based proofs?

2. The Binding Ruling: Process No. 29882 (27 April 2026)

The Portuguese Tax Authority addressed this question through a Binding Information (Informação Vinculativa) dated 27 April 2026. The ruling analysed the case of a company that used an electronic invoicing platform to issue and make credit notes available to its customers. The platform offered the following functionalities: [linkedin.com]

• Automatic document delivery
• Tracking of opening and viewing activity
• Identification of the user accessing the document
• Recording of access date and time
• Retention of access history and tracking logs [nominaurea.pt]

The central question was whether these digital capabilities were sufficient to demonstrate customer awareness and thereby entitle the supplier to adjust (recover) the VAT.

3. The Tax Authority’s Position: Electronic Means Are Admissible

The AT acknowledged that electronic means may be considered valid and suitable for proving customer acknowledgement, provided they ensure four key conditions:

#	Condition	Description
1	Traceability	The system must allow full tracing of the document lifecycle
2	Effective proof of awareness	There must be unequivocal evidence that the customer actually became aware of the credit note
3	Proper documentary retention	Electronic evidence must be archived, organised, and easily retrievable
4	Correct document identification	All communications must accurately identify the nature of the document (credit note, not invoice)

This represents a significant modernisation of the AT’s interpretation: digital platforms are expressly accepted as a legitimate channel for communicating tax-relevant documents. [nominaurea.pt]

4. Why the Specific Case Was Rejected

Despite accepting the principle, the AT rejected the VAT adjustment in the case under review due to several critical shortcomings:

• Incorrect document identification: Emails and tracking files referred to “invoices” rather than “credit notes” — a documentary inconsistency the AT deemed material. [nominaurea.pt]
• Lack of unequivocal proof: Although records showed documents had been opened, the evidence did not clearly demonstrate individual and unequivocal acknowledgement of each specific credit note. [nominaurea.pt]
• Inadequate archiving: Electronic evidence was not properly organised within the company’s accounting records in a manner that would allow easy demonstration of which document was issued, when it was made available, when and by whom it was viewed, and which transaction it related to. [nominaurea.pt]

5. What Companies Must Do: Practical Compliance Checklist

The ruling sends a clear message: digitalisation is accepted, but rigorous control is non-negotiable. Companies using electronic platforms should ensure:

1. Robust communication procedures — Systems must objectively demonstrate that the customer received and became aware of the credit note. [nominaurea.pt]
2. Reliable and auditable tracking — Merely sending the document is insufficient. Companies should retain opening confirmations, access records, viewing history, system logs, and user identification. [nominaurea.pt]
3. Correct documentary identification — All documents, emails, notifications, and records must correctly identify the nature of the tax document. A credit note must always be labelled as a credit note — never as an invoice. [nominaurea.pt]
4. Proper document retention — All electronic evidence should be archived and easily retrievable in the event of a tax inspection. [nominaurea.pt]

6. Consequences of Non-Compliance

Documentary failures may prevent the recovery of adjusted VAT and lead to: [nominaurea.pt]

• Tax corrections
• Additional tax assessments
• Compensatory interest charges
• Contingencies during tax audits

7. Who Is Most Affected?

This guidance is particularly relevant for: [nominaurea.pt]

• Companies using automated electronic invoicing platforms
• Corporate groups with intercompany adjustments
• SaaS platforms and technology-driven businesses
• Logistics and distribution companies
• Businesses with a high volume of VAT adjustments
• Companies with international customers
• Organisations undergoing digital transformation

8. Broader Context: Portugal’s Digital Tax Landscape

This ruling fits within Portugal’s broader push toward digital tax compliance. Key ongoing developments include:

• Mandatory QES (Qualified Electronic Signature) on PDF invoices from 1 January 2027 (postponed from earlier deadlines by the 2026 Budget Bill). [kpmg.com]
• SAF-T accounting file — the first mandatory annual submission for 2026 transactions is now due in 2028. [kpmg.com]
• VAT Grouping regime starting July 2026. [vatupdate.com]
• Alignment with the EU’s ViDA (VAT in the Digital Age) initiative and future digital reporting requirements. [pwc.pt]

Sources

• Nominaurea – VAT Credit Memos in Portugal: New Tax Authority Guidelines (May 2026) [nominaurea.pt]
• Nominaurea – LinkedIn Post on Binding Information Process no. 29882 [linkedin.com]
• KPMG – Portugal: Postponed mandatory use of QES and SAF-T requirements [kpmg.com]
• VATupdate – Portugal Comprehensive VAT Guide 2026 [vatupdate.com]
• PwC Portugal – Modernizing VAT Reporting Obligations [pwc.pt]

---

---