An entity that is an investment entity, is not tax transparent and has not elected under section 111AU or 111AV is a "relevant investment entity" whose effective tax rate is calculated separately from the jurisdiction. The effective tax rate equals the relevant investment entity's adjusted covered taxes divided by the allocable share of the MNE group or large‑scale domestic group in the entity's qualifying income or loss. Where multiple relevant investment entities exist in a jurisdiction, their adjusted covered taxes and allocable shares are combined. The allocable share is determined under section 111I and excludes interests subject to elections under sections 111AU or 111AV.

The adjusted covered taxes comprise the portion attributable to the allocable share of qualifying income plus covered taxes allocated under section 111Z, excluding covered taxes attributable to income outside the group's allocable share. The top‑up tax is (A×(B−C))−D, where A is the top‑up tax percentage (minimum tax rate minus effective tax rate), B is qualifying income, C is the substance‑based income exclusion determined under subsections (1)–(7) and (10)–(12) of section 111AE applied only to eligible tangible assets and eligible payroll costs of eligible employees of the relevant investment entity, and D is the qualified domestic top‑up tax payable; qualifying income and substance‑based exclusions are combined across multiple relevant investment entities.