Infrastructure cost decisions are increasingly made through separate institutional processes, yet their combined effects are ultimately borne by ratepayers. This paper examines that problem through the case of Minnesota Power, where regional transmission planning, utility resource planning, and ownership restructuring converge over the same planning horizon. Using tariff documents, regulatory filings, Integrated Resource Plan (IRP) modeling, and transaction records, it develops the Sequential Institutional Risk Transformation (SIRT) framework to trace how distinct governance decisions are translated into layered ratepayer obligations. The analysis shows that consumer protections attached to the ownership transaction are modest relative to the scale of capital exposure simultaneously being assembled and expire before the period of greatest burden begins. The paper argues that this is not only a regulatory gap but a planning problem: costs can accumulate on communities without any institution evaluating their total impact. It contributes a framework for identifying convergent ratepayer risk and proposes cumulative assessment as a needed planning and regulatory practice.