The re-election of Donald Trump as President of the United States has prompted significant changes in global tax policy discussions, notably the U.S. withdrawal from an international agreement aimed at establishing a 15% global minimum tax on multinational corporations.

This agreement, developed under the auspices of the Organisation for Economic Co-operation and Development (OECD), had been endorsed by 142 countries, including the United States.

However, a recent memorandum signed by President Trump indicates that the U.S. will no longer adhere to this agreement, asserting that commitments made by the previous administration are not binding.

This development has significant implications for countries that have already begun implementing the tax, particularly in the European Union.

Spain, for instance, had planned to enforce the global minimum tax starting December 2024. The U.S. move introduces uncertainties in these countries regarding future international investments and potential retaliatory measures.

The Trump administration's stance is that the global tax agreement infringes on U.S. sovereignty and contradicts domestic goals of economic growth.

President Trump has proposed reducing the nominal corporate tax rate from 21% to 15%.

Legal experts, such as Pablo Gómez-Acebo, predict that the U.S. will selectively apply OECD tax principles only when they benefit domestic revenue collection.

The OECD agreement's purpose is to ensure that multinational corporations pay a minimum tax rate of 15% irrespective of their location, thus discouraging tax evasion through fiscal relocation.

A country failing to implement this policy would allow others to collect the taxes foregone.

As the world's largest economy, the U.S. decision can significantly affect the global taxation system.

Only 32 countries, primarily European, have ratified or are in the process of ratifying the agreement.

Fiscal consultant Juan José Sánchez views the U.S. memorandum as a pivotal development, highlighting an anticipated shift towards more aggressive unilateral tax policies.

The memorandum also alludes to potential U.S. actions against countries implementing the tax, labeling the OECD framework as discriminatory.

It specifies that within 60 days, measures will be proposed to safeguard U.S. economic interests, with the possibility of tariffs similar to those introduced during disputes over the digital services tax in 2019.

European nations face challenging decisions, with limited room to maneuver due to fiscal obligations and welfare funding needs.

While obliged by a 2022 directive to enforce the global tax minimum, there is concern over the potential economic impact of U.S. counteractions.

Some experts suggest that repercussions might lead nations to reconsider their tax strategies.

The potential tax revenue gains from implementing this minimum tax are contingent upon broader international adoption and corporate compliance.

For example, prior estimations by Spain's Ministry of Finance projected additional annual revenues of approximately €2.6 billion.

Overall, the U.S. withdrawal has introduced uncertainties and complexities in the ongoing efforts to standardize global corporate taxation, affecting investment decisions and international fiscal policies.