Looming Global Minimal Tax Deadlines Require Clarity and Urgency

As the first filing deadline, June 30, to comply with the global 15% minimum tax regime draws closer, businesses are facing unprecedented compliance challenges.

Multinationals are devoting significant resources to complying with Pillar Two of the Inclusive Framework while critical elements of the compliance infrastructure are still missing and persistent gaps in operational readiness across jurisdictions are creating uncertainty and taxpayer risk.

In numerous countries, GloBE information return (GIR) and qualified domestic minimum top-up tax forms haven’t been finalized, electronic filing portals aren’t fully operational, and final technical specifications—including XML schemes—remain unavailable. Meanwhile, the system for automatic exchanges of GIR information under the multilateral competent authority agreement is incomplete.

These gaps would be concerning in any context. They’re especially troubling in a regime where late, incomplete, or technically non-compliant filings can attract penalties, trigger procedural consequences, or jeopardize access to safe harbors—even for most in-scope multinationals for which there is no top-up tax or liability is immaterial.

Limited Operational Readiness

Available public information paints a clear picture of uneven, and often insufficient, operational readiness across implementing jurisdictions.

No more than a handful of jurisdictions with imminent Pillar Two filing obligations have finalized forms and operational process. Most others lack complete forms, functioning portals, or final guidance. Where some countries have performed dry run exercises, the outcome has been disturbing, with high levels of formal system rejections of the returns.

This isn’t a marginal issue affecting a handful of late adopters. It reflects a systemic bottleneck at the very point when businesses must finalize systems, validate data, and test reporting processes. Releasing forms or technical specifications only shortly before filing deadlines undermines the ability to comply accurately and consistently, particularly for large multinational groups operating across dozens of jurisdictions.

The status of information exchange compounds this problem. Many multinational enterprises have reasonably planned on the basis that the GIR would be filed centrally and exchanged between tax administrations, consistent with Inclusive Framework commitments.

This assumption breaks down where multilateral competent authority agreement exchange relationships aren’t yet activated or technical infrastructure is incomplete. Forcing businesses into last-minute contingency planning for widespread local filings is impractical and unreasonable given resourcing and systems constraints.

Beyond resourcing challenges, local filing raises longstanding concerns about the breadth of dissemination of highly sensitive group-level information, including the risk that data could be used for purposes beyond Pillar Two. These concerns have been raised consistently since the inception of the project and remain unresolved.

Broader Compliance Risks

Despite these readiness gaps, most implementing jurisdictions have legislated penalties for late or incorrect filings, frequently without clear confirmation of first-year relief. Importantly, this exposure exists even where no Pillar Two top-up tax is due, notwithstanding the GIR’s nature as a pure information return.

Monetary penalties are only part of the risk. In several jurisdictions, late or failed filings have procedural consequences, including challenges to qualified domestic minimum top-up tax positions, loss of safe harbor protections, loss of access to important elections, and heightened audit and dispute risk.

These outcomes can’t necessarily be remedied through penalty waivers alone and raise serious questions about proportionality and legal certainty in the first year of implementation.

At the same time, significant areas of administrative guidance remain outstanding. Uncertainty persists around foreign currency and hyperinflation issues, the application of the substance-based income exclusion to mobile assets, and the treatment of investment entities, among others.

For many groups, these open issues directly affect jurisdictional effective tax rates and GIR data points and represent blockers to complete compliance.

Coordinating Transitional Solutions

The challenges described above are systemic and can’t be effectively resolved through fragmented unilateral measures or non-binding assurances. We strongly urge the OECD and implementing jurisdictions to provide for coordinated transitional solutions that would materially improve outcomes without delaying top-up tax collection, including in particular:

• A coordinated extension of local GIR filing deadlines (for example, by six months), or deferral until filing portals, forms, and exchange mechanisms are fully operational across jurisdictions.
• A clear and consistent first-year “soft landing” approach, under which no penalties or adverse procedural consequences apply, including the continued acceptance of taxpayer elections by jurisdictions, where taxpayers act in good faith and any delays arise from legal, technical, or operational constraints beyond their control. This approach must allow multinationals to always be able to elect for central GIR filing, even in cases where the exchange of information instrument hasn’t been activated.

Providing transitional relief wouldn’t delay or undermine revenue collection. Instead, it would improve data quality, reduce the need for corrective filings, and enhance confidence in the administrability of the regime at launch.

As businesses finalize their first GIRs, urgent clarity is needed on filing expectations, exchange assumptions, and the availability of transitional relief. Early, coordinated communication will benefit taxpayers and tax administrations themselves—and help determine whether Pillar Two’s first year is remembered as a controlled and credible rollout or one marked by avoidable compliance challenges.

Consulting with businesses ensures that tax policies support these objectives. The OECD and the Inclusive Framework continue to play an essential role as the forum for multilateral cooperation on international tax.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law, Bloomberg Tax, and Bloomberg Government, or its owners.

Author Information

Christian Kaeser is co-chair of Business at OECD’s tax committee and the global head of tax at Siemens.

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