[en] Highlights: • Greater political control allows more deviations between prices and marginal costs. • Competitive area residential and commercial prices better reflect costs. • Residential margins declined in competitive but not non-competitive areas. • More commercial to residential cross-subsidization in non-competitive areas -- Abstract: Electricity market reforms have pursued two goals, both aimed at increasing economic efficiency. The first is to ensure that suppliers minimize costs. The second is to make prices more reflective of marginal costs. We use data from Texas to examine whether post-reform retail prices have better reflected wholesale prices, and whether reform has reduced retailer costs. We find clear evidence of both outcomes in competitive market areas but not in non-competitive areas supplied by municipally-owned utilities or co-operatives.