Bulgaria's parliament adopted amendments updating Annex A taxes to include corporate minimum surtaxes.
Bulgaria tightens net on corporate giants with three taxes
Parliament amends an international treaty to exchange data on multinationals under global minimum tax rules.
In a nutshell
Bulgaria has updated its ratification of a joint OECD and Council of Europe tax treaty to include three corporate surtaxes from its Corporate Income Tax Act. The legislative vote bridges domestic minimum tax rules into global enforcement networks, allowing Bulgarian authorities to conduct joint audits and exchange financial records with foreign tax inspectors.
Highlights
- Bulgaria adopted the convention update on both first and second reading on September 10, 2026.
- The amendment adds three levies to Annex A: a primary surtax, a secondary surtax, and a national top-up tax.
- Domestic corporate rules governing large groups took effect across 2024 and 2025.
- The government must file a formal notification with the OECD depositary after State Gazette promulgation.
From the Editor’s Diary
Enforcing minimum taxes on global corporations requires domestic statutes to match international sharing treaties, because domestic law alone cannot compel cross-border audits.
Who's involved
National Assembly of Bulgaria
The unicameral national parliament and supreme legislative body of Bulgaria
goal → Wants to align domestic legislation with OECD commitments and international tax standards
Lyudmila Petkova
Deputy Minister of Finance of Bulgaria
goal → Wants to establish the legal basis for international administrative tax cooperation and OECD notifications
OECD
Organisation for Economic Co-operation and Development, an international policy organisation
goal → Seeks worldwide implementation of multilateral tax assistance and Pillar Two minimum corporate tax rules
In short
Bulgarian tax inspectors have gained legal backing to share audit data and demand corporate records across borders, removing a roadblock to tracking corporate earnings stashed abroad.
The vote paves the way for Bulgaria to enter automated, cross-border tax investigations alongside foreign revenue services.
This step is near-certain to take effect quickly because the legislature passed the statutory revision on both required readings in a single day, leaving only formal publication and routine treaty filing to conclude it.
How it unfolded
Bulgarian Lawmakers Approve Cross-Border Tax Review
Bulgaria's parliament removed a legal bottleneck on September 10, 2026, passing legislation on both first and second reading to update its ratification of the multilateral tax-assistance convention, as reported by state news agency BTA.
Expanding Treaty Annex for Multinational Information Exchanges
Following the debate in Sofia, Deputy Finance Minister Lyudmila Petkova said the amendment lists three surtaxes—primary, secondary, and national—under Annex A of the international convention. While Bulgaria brought corporate minimum tax rules into local law across 2024 and 2025, officials could not exchange standardized multinational returns under international agreements until lawmakers formally added these levies to the treaty schedule.
Where things stand
Lawmakers passed the bill through both legislative readings. The government must now publish the measure in the official State Gazette and send a formal notice to the OECD treaty depositary to enact the cross-border provisions.