Downstream price-cap regulation and upstream market power

Under “partial separation,” it is increasingly common for a utility’s upstream affiliate (e.g., an electric generation supplier) to be unregulated while its downstream affiliate (e.g., the distribution company offering retail service) is subject to regulation. When choosing the optimal form of downstream regulation, regulators may be confronted with the potential exercise of market power by the upstream affiliate. This paper finds that the imposition of a downstream price cap with an appropriate profit-sharing rate can eliminate the upstream affiliate’s exercise of market power. However, it is less desirable to fully mitigate affiliate market power when upstream rivals also behave strategically.