Book excerpt: This study examines the question of private versus public performance in a natural monopoly setting. It analyzes data from 301 utilities with private sector participation (PSP) and 926 utilities without PSP in 71 developing and transition economies to evaluate the impact of PSP on firm performance in electricity distribution and water and sanitation services. Private participation is shown to be associated with an increase in connections, labor productivity, and bill collection rates, and a decrease in employment and electricity distributional losses.