The OECD has today released the 2026 Economic Impact Assessment of the Global Minimum Tax (GMT), providing new estimates of the expected effects of the GMT and presenting preliminary evidence from its first year of implementation. The findings were presented during an OECD webinar held today.
The updated assessment incorporates more recent data, improved modelling, and information on the current state of GMT implementation and the recently agreed Side-by-Side Package. It examines the expected effects of the GMT on effective tax rates, tax rate differentials, profit shifting and tax revenues.
The OECD also released a separate analysis, MNE Responses to the GMT, based on 2024 consolidated financial statement data, providing an initial assessment of outcomes following the first year of GMT implementation. The preliminary evidence suggests increases in effective tax rates among in-scope multinational enterprises relative to out-of-scope firms, while finding no statistically significant evidence of reductions in investment or employment among in-scope firms during the first year of implementation.
Key findings
Relative to a hypothetical scenario where the GMT was not implemented anywhere, the analysis found the following expected effects, noting these may take time to be realised.
- Average jurisdiction-level effective tax rates are estimated to increase by 2.8-3.7 percentage points on average under the current GMT framework, with effective tax rates in investment hubs estimated to rise by 5.5-6.9 percentage points.
- Effective tax rate differentials between jurisdictions are estimated to decline by 19-25%, potentially leading to improved allocation of capital.
- The GMT is estimated to reduce profit-shifting substantially with an estimated reduction of between 22.6-44.6%.
- Global CIT revenues are estimated to rise by 3.2-5.4% per year.
- Initial post-implementation 2024 data suggests positive effective tax rate impacts of the GMT and finds no evidence of negative effects on investment or employment.
Today’s webinar outlined the methodology, assumptions and results of the updated assessment and provided stakeholders with an opportunity to discuss the analysis and its implications. The webinar highlighted the role of the GMT in strengthening international tax co-operation, reducing BEPS activity, and enhancing stability in the international tax system.
The OECD will continue to monitor the implementation and impacts of the GMT as additional data become available. The updated assessment and accompanying analysis are intended to support the ongoing evaluation of the GMT and its effects over time.
For more information, including the working paper and webinar materials, visit: https://www.oecd.org/en/events/2026/07/economic-impact-assessment-of-the-global-minimum-tax-2026.html.
For more information on the OECD’s work on the Global Minimum Tax, visit: https://www.oecd.org/en/topics/sub-issues/global-minimum-tax.html.
For further information, please contact the Communications Office in the OECD Centre for Tax Policy and Administration.
