The cost-effectiveness of cap-and-trade emissions regulations has become widely accepted. A 2009 proposal by Muller and Mendelsohn would replace conventional ton-for-ton trading with trading based on estimates of marginal damages by pollutant and by source. This proposal faces difficulties arising from the negative marginal damage estimates—neglected in Muller and Mendelsohn (2009)—for nitrogen oxide (NOx) emissions from many urban counties. Such estimates imply nonconvexities in air chemistry that complicate trading and could result in trades that increase emissions by both buyer and seller. Uncertainty in source-specific damages also creates rent-seeking opportunities and the potential for costly litigation. JEL: H53, Q53, Q58

We focus on the effect of state versus private ownership on the rates of firm-specific productivity growth and cost decline by developing a model of endogenous, firm-specific productivity growth and testing its implications against panel data on 23 international airlines of varying levels of state ownership over the period 1973-83. Our model and empirical results show that state ownership can lower the long-run annual rate of productivity growth or cost decline, but not necessarily their levels in the short run. Observed level differences in productive efficiency across private and state-owned firms may thus be a function of the age distribution of the firms being compared. These results appear to be independent of whether the firms operate under apparently more or less competitive or regulated markets and whether they differ in production scales. The analysis offers new insights concerning the recent trend toward privatizing state-owned enterprises that has been observed in many countries.