When providing public goods through voluntary contributions, a donor may introduce unilateral matching in order to reduce underprovision of the public good and thus inefficiency. By itself, however, matching benefits the donor but harms the recipient. We apply Cornes and Hartley’s aggregative...

We study (energy) markets with dirty incumbents and costly entry by clean producers. For intermediate entry costs, the market outcome exhibits inefficient production and inefficient entry. A policy mix of three popular regulatory instruments—taxation on polluters, feed-in tariffs for clean...