The Global Minimum Tax (GMT) was conceived as a corrective to decades of base erosion and profit shifting. Its promise was simple in principle: multinational enterprises would pay at least a 15 percent effective tax rate wherever they generate profits, limiting the ability to arbitrage between jurisdictions.
Yet as implementation unfolds, the effectiveness of the Global Minimum Tax is increasingly shaped not by intent, but by design.
The OECD/G20 Inclusive Framework’s January 2026 agreement on the Side-by-Side Package represents a pivotal design shift. While framed as a set of technical refinements—new safe harbours, revised treatment of tax incentives, and compliance simplifications—the package has material implications for how taxing rights are allocated between residence and source countries.
For African economies, these stakes are substantial.
The Global Minimum Tax and Africa’s original concern
Under the GloBE rules, jurisdictions may introduce a Qualified Domestic Minimum Top-Up Tax (QDMTT) to secure priority taxing rights over profits earned within their borders. Absent such measures, top-up taxes may be collected by residence jurisdictions through the Income Inclusion Rule (IIR) or, failing that, through the Undertaxed Profits Rule (UTPR).
This structure placed African countries at a crossroads. Many levy statutory corporate income tax rates above 15 percent, yet effective tax rates are frequently driven lower by incentives, exemptions, and administrative weaknesses. Without a domestic response, the Global Minimum Tax risked reallocating revenue away from the continent rather than strengthening domestic resource mobilisation.
The Side-by-Side Package does not remove this risk. It reshapes it.
Side-by-Side safe harbours and differentiated outcomes
The introduction of the Side-by-Side Safe Harbour and the Ultimate Parent Entity Safe Harbour acknowledges that certain jurisdictions may operate domestic tax systems deemed functionally equivalent to the Global Minimum Tax, even without full adoption of the GloBE rules.
In principle, safe harbours are designed to reduce compliance burdens and allow tax administrations to focus on higher-risk cases. In practice, eligibility criteria—high nominal tax rates, comprehensive taxation of foreign income, and alternative minimum taxes based on financial accounts—remain concentrated in advanced economies.
The confirmation of the United States as eligible under the Side-by-Side Safe Harbour illustrates this asymmetry.
For African source countries, the implication is clear: multinational groups headquartered in Side-by-Side jurisdictions may avoid full GloBE calculations, while profits generated in Africa remain exposed to top-up taxation elsewhere unless domestic safeguards are in place.
QDMTTs remain central, but timing matters
The Inclusive Framework has reaffirmed the central role of Qualified Domestic Minimum Top-Up Taxes, including explicit confirmation that QDMTTs must apply on a non-discriminatory basis and cannot exclude entities benefiting from Side-by-Side regimes.
This protection is significant. But it does not eliminate urgency.
Without timely introduction of QDMTTs or equivalent domestic measures, African countries risk continued leakage of taxing rights—now potentially through Side-by-Side regimes rather than solely through the IIR or UTPR.
Tax incentives and the softening of discipline
One of the Global Minimum Tax’s early strengths was its indirect pressure on inefficient tax incentives. Income-based incentives and tax holidays became less attractive once they merely triggered top-up taxes elsewhere.
The Side-by-Side Package partially relaxes this constraint.
Certain expenditure-based and production-based incentives may now qualify as “Qualified Tax Incentives,” increasing an enterprise’s effective tax rate for Global Minimum Tax purposes rather than reducing it. This treatment is subject to a substance-based cap linked to payroll and tangible assets.
For African economies, this change is not neutral. Capital-intensive sectors—such as extractives, telecommunications, and manufacturing—often involve significant tangible assets, meaning the substance cap could permit substantial incentive-related revenue losses.
While income-based incentives remain excluded, the revised treatment risks re-legitimising forms of tax competition the Global Minimum Tax was intended to curb.
Simplification and administrative trade-offs
The package’s simplification measures—including the Simplified Effective Tax Rate Safe Harbour and the extension of the transitional Country-by-Country Reporting safe harbour—aim to reduce compliance burdens for both taxpayers and administrations.
Simplification, however, reallocates attention. Reduced calculation requirements place greater weight on initial policy design and domestic enforcement capacity. For African tax administrations, the challenge lies in adopting simplifications without weakening their ability to detect revenue risks.
Why design now determines outcomes
The Side-by-Side Package confirms that the Global Minimum Tax is no longer a static settlement. It is an evolving system in which technical design choices shape real revenue outcomes.
For Africa, the central question remains unchanged: will profits generated from real economic activity on the continent be taxed there, or elsewhere?
The answer increasingly depends on domestic policy timing, institutional readiness, and sustained engagement in global rule-making processes. Intent alone is no longer sufficient.
In the Global Minimum Tax era, design decides outcomes—and Africa’s response to the Side-by-Side turn will help determine whether the reform delivers on its original promise.
