SARS Activates Global Minimum Tax Interest Calculation from 1 July 2026

South Africa's tax authority has formally gazetted the date from which the interest calculation method applies to liabilities arising under the Global Minimum Tax Act, 2024. The notice, published in Government Gazette 54921 on 30 June 2026 and effective 1 July 2026, locks in how interest imposed under section 7 of that Act is to be computed, read together with Chapter 12 of the Tax Administration Act, 2011. For accounting firms advising multinational groups with a South African presence, this is an operational trigger, not a policy announcement to file and forget.

The Legal Mechanics: What the Gazette Actually Says

The notice was issued in terms of section 187(2) of the Tax Administration Act, 2011, which gives SARS the authority to prescribe, by public notice, specific procedural or computational rules that supplement the principal legislation. In this case, the prescribed rule concerns interest that accrues when a taxpayer underpays or is late in meeting an obligation under section 7 of the Global Minimum Tax Act, 2024.

The Interaction Between the GMT Act and Chapter 12 TAA

Chapter 12 of the Tax Administration Act is the general interest regime. It sets out when interest starts running, the applicable rate references, and how compounding works across different tax types. By explicitly linking section 7 GMT liabilities to that chapter, SARS has brought the new minimum tax squarely into the same interest framework used for income tax and other assessed taxes. The gazette prescribes the date from which this linkage is operative: 1 July 2026.

That means any shortfall or late payment of a Qualifying Domestic Minimum Top-up Tax or an Income Inclusion Rule liability that falls due on or after that date will attract interest calculated under the Chapter 12 methodology. Advisers should not assume the interest treatment that applied to any transitional period filings automatically carries over under the same terms.

Why This Matters for Accounting Firms Right Now

The Global Minimum Tax Act, 2024 introduced South Africa's implementation of the OECD Pillar Two framework, targeting large multinational enterprise groups whose consolidated revenue meets the threshold. The Act itself set out the charging provisions. What was still outstanding, until this gazette, was certainty on how interest would be computed if those charges were not paid on time or were under-declared.

Practical Implications for Compliance Workflows

Firms running compliance workflows for affected clients need to update their processes in several specific ways:

Interest exposure modelling. Any scenario or cash-flow model built for a client's GMT position should now incorporate the Chapter 12 interest mechanics as the confirmed calculation basis. Using a generic or estimated interest rate without anchoring to Chapter 12 creates advisory risk.

Payment timing decisions. Where a client is uncertain about the correct top-up tax amount and is considering provisional or protective payments, the confirmed interest method changes the cost-benefit calculus of paying early versus waiting for a final determination.

System configuration. Teams using digital asset accounting software or broader crypto bookkeeping software to track group-level tax positions should verify that the interest accrual logic in those tools can accommodate the Chapter 12 rate and compounding rules. The same applies to any crypto accounting software deployed within a group treasury or tax function that captures intercompany transactions subject to GMT allocation.

Record-keeping start date. Because interest runs from 1 July 2026, that date becomes the earliest point at which a late-payment interest charge can legally accrue under the new method. Documentation of payment dates, settlement references, and SARS correspondence from that date forward will be critical if a dispute arises.

Gazette Reference and Timing

Key Administrative Details

The notice appears in Government Gazette number 54921, dated 30 June 2026. The operative date for the interest calculation method is 1 July 2026. The authority for the notice is section 187(2) of the Tax Administration Act, 2011, and the charging provision being regulated is section 7 of the Global Minimum Tax Act, 2024, in conjunction with Chapter 12 TAA.

Firms should pull a copy of the full gazette notice directly from the SARS legal counsel page and attach it to the client file. The notice itself is brief, but its downstream effect on interest exposure calculations is material. For groups with more complex structures, for instance where both an Income Inclusion Rule charge and a Qualifying Domestic Minimum Top-up Tax may apply, the interaction of multiple charges under the same Chapter 12 interest regime should be modelled separately for each liability type.

Understanding how Pillar 2 qualified status works in practice across different jurisdictions is also relevant context here, particularly for groups that have entities in multiple OECD-implementing countries and need to determine where top-up tax is actually paid. Separately, recent OECD minimum-standards treaty developments illustrate how quickly the international tax landscape is moving, reinforcing the case for keeping domestic implementation dates such as this one on active monitoring lists.

What Firms Should Do Before Processing the Next GMT Payment

The steps below are immediate, not deferred to the next quarterly review.

Checklist for the Coming Days

First, confirm which clients are in scope for the GMT Act. The threshold is based on consolidated group revenue; not every multinational qualifies. Second, brief the relevant partner or manager on the effective date so that any payment instructions issued after 1 July 2026 are flagged for interest exposure review. Third, cross-check the interest rate that Chapter 12 currently prescribes, as SARS publishes the applicable rate periodically, and verify that your calculation tools are using the current figure. Fourth, update engagement letters or advisory scope documents if interest exposure modelling under the GMT Act was not previously included as a deliverable. Fifth, check whether any GMT filing or payment that was due on or near 1 July 2026 has already been submitted, and if so, confirm whether the Chapter 12 method was applied or whether a correction may be needed.

Firms that have deferred building a GMT compliance process on the assumption that SARS would provide more detailed guidance before enforcement started should treat this gazette as a signal that the administrative machinery is now active.

Source: South African Revenue Service