Beyond Project IRR: A Sovereign Return Framework for Metropolitan Investment

Conventional project investment appraisal focuses primarily on the cash flows, profitability and financial sustainability of the project entity. Public or sovereign metropolitan investment, however, may generate costs and benefits that fall outside the project vehicle, including fiscal effects, productivity, employment, resilience, human-capital formation, strategic capability and exportable knowledge. This paper develops a Sovereign Return Framework for metropolitan investment that distinguishes project/developer return from broader national value while avoiding the common analytical errors of double counting, transfer inflation and unsupported monetization. The research question is: how can sovereign value from metropolitan investment be evaluated beyond project IRR while remaining consistent with established public-investment appraisal principles? The framework is positioned against social cost-benefit analysis, public-investment management, the 2026 HM Treasury Green Book and World Bank guidance distinguishing financial from economic analysis. Seven positive return accounts are proposed: development, operating, fiscal, national economic, capability, resilience and export return. These are reconciled against negative accounts including CAPEX, OPEX, renewal, financing cost, opportunity cost, import leakage, stranded capacity, activation gaps, contingent liabilities, externalities and failure risk. The paper does not propose a single synthetic sovereign IRR. Where benefits can be monetized defensibly, they may be assessed using discounted cash-flow or social cost-benefit methods. Where they cannot, they remain separately reported decision variables. The principal contribution is therefore a structured metropolitan decision account rather than a new finance metric. The framework remains conceptual and requires empirical calibration, jurisdiction-specific fiscal rules, distributional analysis and independent economic review before use in formal investment approval.