In a jurisdiction with a newly-restructured electric utility market, a single proceeding encompassed the rates of multiple generating utilities, a power pool that aggregated and re-distributed the cost of those generators, multiple transmission providers, a similar transmission-aggregation utility and multiple distribution utilities. A change in the cost of any one affected several of the others. We prepared a suite of linked financial models that enabled the regulator to evaluate the effect of changes in the values (e.g., in return on equity) and how those flowed through to all the other utilities. Few projects are this complex, but we often provide regulators and clients with financial models that enable them to test the effects of different assumptions and inputs.