Key 2026 Changes to Tax Return Deadlines

• The deadline for submitting the income tax return (TD4 for companies, TD1 for self-employed with audited accounts) for tax year 2023 has been extended to 31 March 2026 (previously 30 November 2025). For tax year 2024, the deadline has been extended to 30 November 2026 (previously 31 March 2026). Both extensions were issued via Decrees KΔΠ 358/2025 & 359/2025 on 28 November 2025 and apply equally to the Summary Information Table (SIT) for controlled transactions under Article 33.
• Going forward, the corporate tax return deadline has been permanently moved to 31 January of the second year following the assessment year. This first applies to 31 January 2028 for the 2026 tax year. This change allows additional time for companies to prepare audited financial statements and ensure accuracy in their tax filings.
• The annual TD7 employer return deadline has moved from 28 February to 31 March, providing employers with additional time to compile payroll data. For the 2025 annual TD7 specifically, the deadline is 31 May 2026.

Document Retention Requirements

• From 2026, the document retention period has been extended to 6 years from the submission deadline of the relevant tax return. This applies to all tax documentation, supporting records, and evidence of business transactions. Taxpayers must maintain organised records to satisfy this requirement and facilitate tax audits.

Administrative Penalties

The 2026 reform introduces a tiered penalty structure based on entity size (determined by the previous year’s gross income). Penalties now vary depending on the nature of the violation and whether the entity’s gross income exceeds €1,000,000.

Violation	≤€1M Gross Income	>€1M Gross Income
Late filing of tax return	€150	€500
Late submission of supporting documents	€150	€500
Failure to maintain records / retain documents	€300	€1,000
Failure to file employer returns (TD7)	€300	€1,000
Late payment of tax	5% penalty + additional 5% if unpaid after 2 months

Escalation: Where a taxpayer does not remedy the violation within 60 days of a formal notice from the Commissioner, additional penalties may be imposed. The Commissioner has discretion to escalate penalties for persistent non-compliance, and multiple violations can accumulate (each attracts its own penalty independently).

Public Interest Rate for Late Payment

The interest rate for late tax payments is determined by Ministerial Decree and is applied monthly on overdue tax amounts, accruing from the original due date until full payment. For 2026 the rate is 3.5% per annum (decreased from 5.5% in 2025). This is charged in addition to the 5% monetary surcharge (and additional 5% if unpaid after 2 months) described in the penalties table above.

Period	Interest Rate (%)
Up to 31/12/2006	9
1/1/2007 – 31/12/2009	8
1/1/2010 – 31/12/2010	5.35
1/1/2011 – 31/12/2012	5
1/1/2013 – 31/12/2013	4.75
1/1/2014 – 31/12/2014	4.5
1/1/2015 – 31/12/2016	4
1/1/2017 – 31/12/2018	3.5
1/1/2019 – 31/12/2019	2
1/1/2020 – 31/12/2022	1.75
1/1/2023 – 31/12/2023	2.25
1/1/2024 – 31/12/2024	5
1/1/2025 – 31/12/2025	5.5
1/1/2026 – 31/12/2026	3.5