We compare two cooperation mechanisms for consumer/producers of a public good: the Nash Bargaining Solution (NBS) and the Exchange-Matching-Lindahl (EML) solution, where each agent specifies her demand for and supply of the public good according to her personal exchange rate. Both mechanisms are Pareto-efficient. EML is equivalent to matching. In our specific model with linear or quadratic benefits and quadratic costs, EML and NBS are equivalent when there are two agents. With more than two agents, the high-benefit/low-cost agents are better off under EML. We also analyze outsourcing, where agent i can pay agent j to produce the amount that agent i promised to contribute. In our specific model, payments from high-cost to low-cost agents (and from high-benefit to low-benefit agents) are (usually) lower in EML than in NBS.

We focus on the incentives of an industry with a continuum of small firms to invest in a cleaner technology under two environmental policy instruments: tradable emission permits and emission taxation. We assume asymmetric information, in that the firms' abatement costs with the new technology are either high or low. Environmental policy is set either before the firms invest (commitment) or after (time consistency). Under commitment, the welfare comparison follows a modified Weitzman rule, featuring reverse probability weighting for the slope of the marginal abatement cost curve. Both instruments can lead to under- or overinvestment ex post. Tradable permits lead to less than optimal expected new technology adoption. Under time consistency, the regulator infers the cost realization and implements the full-information social optimum.