JIASUJIE

In the period from 2025 through 2030, the global tax landscape stands on the brink of transformative change driven by the Organisation for Economic Co-operation and Development’s Two-Pillar international tax package, anchored around a coordinated global minimum corporate tax designed to curb profit shifting, base erosion, and harmful tax competition. At the heart of this reform are the OECD’s Pillar One and Pillar Two frameworks, with Pillar Two establishing a 15 percent global minimum tax on large multinational enterprises and imposing new compliance obligations that challenge long-standing corporate tax planning models and investment strategies for multinationals, U.S. multinationals included, investors, and tax advisers alike. The global minimum tax, also known as the Global Anti-Base Erosion (GloBE) rules, requires in-scope multinational groups with consolidated revenues above a threshold, roughly $825 million, to calculate effective tax rates on a jurisdictional basis and ensures that those rates meet or exceed a global minimum. If a jurisdiction’s effective rate is below the 15 percent floor, a top-up tax is levied, fundamentally reducing the benefits of low-tax jurisdictions and undermining decades of tax competition among nations. Under the GloBE rules, effective tax rate calculations include detailed adjustments for covered taxes and income, and many jurisdictions have already incorporated qualified domestic minimum top-up tax rules into their domestic legislation as part of the transition to this new era of tax governance. Global implementation efforts, involving more than 65 jurisdictions to date, reflect both the breadth and complexity of the reform and impose a fresh tax paradigm that demands substantive tax planning responses from corporate tax directors and investment managers.

For U.S. multinationals, which have historically maintained substantial portions of their foreign profits in tax-advantaged offshore subsidiaries, the global minimum tax is particularly consequential. Estimates suggest that roughly 69 percent of the foreign profits of U.S. multinationals are reported in jurisdictions with low or zero taxes, intensifying the potential impact of a 15 percent floor on earnings and effective tax rates. GloBE’s rules include a “substance carve-out” that respects a percentage of payroll and tangible assets, phasing down over a decade to focus the minimum tax more on intangible income and profit shifting practices. This carve-out aims to preserve incentives for genuine economic activity in lower-tax jurisdictions while still discouraging profit shifting, but it simultaneously raises the stakes for tax compliance and financial reporting. If the United States adopts GloBE rules, multinational groups will confront a vastly different international tax burden, and if the U.S. does not adopt these rules while other jurisdictions do, U.S. tax authorities and corporate taxpayers may experience asymmetrical tax outcomes.

In parallel with the GloBE top-up tax, the OECD’s Two-Pillar framework also includes the subject-to-tax rule (STTR), a treaty-based mechanism allowing source jurisdictions to tax certain payments subject to very low nominal tax rates in residence jurisdictions, typically below nine percent, under bilateral tax treaties. The STTR represents an additional instrument for developing economies and source countries to protect their tax base in cross-border transactions subject to loopholes under traditional treaty tax allocation rules. It complements the minimum tax and is part of a broader multilateral package that urges countries to modernize tax treaty networks and reduce avoidance through mismatches in domestic tax regimes.

The global minimum tax’s revenue impacts are significant. Implementation of the global minimum tax and related measures could generate between $155 billion and $192 billion in additional corporate income tax annually, equating to a material shift in global tax burden and a reduction in incentives for profit shifting. Profit shifting itself is central to the rationale for these reforms, as research underscores how multinational enterprises have historically shifted profits into low-tax jurisdictions, diminishing the tax base of higher-tax jurisdictions and skewing investment incentives. By reducing tax rate differentials across jurisdictions and lowering the volume of low-taxed profit, the global minimum tax aims to stabilize tax revenues and bring greater fairness to international taxation.

U.S. tax policy response has been complex and politically nuanced. The United States, which has its own controlled foreign corporation regime through Global Intangible Low-Taxed Income (GILTI) provisions, faces a choice between aligning its domestic rules with GloBE or diverging and relying on domestic minimum tax rules coupled with strategic carve-outs. This choice carries implications for both federal revenues and corporate tax planning strategies. Projections suggest that if the U.S. adopts GloBE while other countries do not, U.S. revenues could increase significantly, whereas if the rest of the world implements GloBE and the United States does not, U.S. revenues could fall, highlighting the strategic revenue balances at play in global tax policy alignment. Domestically, legislative proposals have included changes to existing anti-base erosion mechanisms, and political negotiations have grappled with provisions relating to retaliation taxes or aligning U.S. tax law with international norms.

Yet the path to a fully harmonized global minimum tax has not been linear. In 2025, the G7 nations reached a significant understanding regarding the implementation of Pillar Two rules, which includes proposals to exclude U.S.-parented groups from certain core provisions of the original GloBE top-up tax model, offering instead a “side-by-side” approach where U.S. domestic tax rules apply for these groups. This negotiated outcome, which responds to U.S. concerns about competitiveness and sovereignty, is poised to reshape compliance obligations for American companies operating abroad and has drawn scrutiny from other countries objecting to perceived carve-outs that could erode the effectiveness and fairness of the minimum tax regime. Observers note that while the G7 side-by-side solution may preserve clarity and accommodate existing U.S. tax rules, it also complicates multilateral consensus and may undermine equity objectives central to the original OECD framework.

From a corporate tax planning perspective, these developments necessitate sophisticated modeling of tax liabilities across jurisdictions, integration of global tax compliance strategies into enterprise resource planning systems, and proactive restructuring of legal entities. Tax directors must review transfer pricing policies, intercompany financing arrangements, and the allocation of intangible assets while considering the implications of GloBE and STTR rules. Large multinationals, particularly those in technology, pharmaceuticals, and other high-intangible income sectors, face heightened scrutiny because intangible profits are most easily shifted and are therefore a primary focus of the minimum tax. These firms must evaluate whether their current structures will trigger top-up taxes in key markets and adapt by potentially repatriating functions, increasing substance in particular jurisdictions, or restructuring supply chains—a strategic overhaul not seen since the advent of the original Base Erosion and Profit Shifting project in the early 2010s.

For investors, the advent of a global minimum tax brings its own set of considerations. Higher effective tax rates on global profits may influence after-tax returns on foreign investments, especially in multinational corporations with significant low-tax jurisdiction earnings. Changes in effective tax burdens could affect valuation models, stock buyback strategies, and dividend forecasts. Pension funds, mutual funds, and individual investors with exposure to multinational equities should consider how tax reform affects corporate earnings profiles and cash flows. The interaction between foreign tax credits under U.S. law and the global minimum tax further compounds these effects, as higher foreign taxes may reduce U.S. corporate tax liabilities through credits but might also depress net income available for distribution. These dynamics underscore the importance for portfolio managers to incorporate tax policy scenarios into investment risk assessments and long-term asset allocation decisions.

Governments outside the OECD’s core membership, including developing economies and emerging markets, also grapple with this shift. While the global minimum tax aims to protect revenue bases by limiting profit shifting to tax havens, some emerging economies worry that static minimum rates might not reflect their development needs or broader fiscal strategies. The STTR’s treaty mechanisms allow source jurisdictions to reclaim taxation rights on certain low-taxed payments, offering a tool for developing countries to strengthen their tax base. However, balancing domestic revenue goals with the administrative complexity of implementing and enforcing new rules remains a challenge. Diplomatic negotiations continue, and the coming years will likely see further multilateral adjustments aimed at improving fairness, integration with digital taxation measures, and broader acceptance of the minimum tax framework.

In conclusion, the 2025–2030 era of global tax reform centered on the OECD’s global minimum tax and Two-Pillar solution represents a fundamental shift in how governments tax multinational enterprises, how companies plan their global tax strategy, and how investors assess risk and return. The imposition of a 15 percent minimum effective tax rate, complemented by treaty-based rules like the STTR, reduces incentives for profit shifting and base erosion, increases global tax revenues, and creates a more predictable international tax framework. For U.S. multinationals and investors, these reforms present both challenges and opportunities: the imperative to adapt tax planning strategies in an environment of greater multilateral coordination and to identify new pathways for optimizing investment returns in a world where international tax competition yields to coordinated tax governance. As reforms solidify and domestic implementations evolve through 2030, tax professionals, CFOs, and global investors alike must maintain agility, forward-thinking strategies, and robust compliance infrastructures to thrive in this new global tax paradigm.