Brattle principals have researched the impact of revenue decoupling on electric and natural gas utilities cost of capital in several different contexts and timeframes. For our article, “Decoupling and the Cost of Capital,” we assembled a detailed 10-year database of the market returns of 14 utility holding companies and a corresponding index to measure the precise level of decoupling within those companies. We found that statistical evidence does not support the hypothesis that the adoption of decoupling results in a statistically significant reduction in the cost of capital. This has been a general finding of our other studies.

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