Under the innovative, market-based approach to acid rain control included in the Clean Air Act amendments of 1990 (CAAA), sulfur dioxide emission allowances allocated to existing electric utility sources of these emissions can be used by utilities, banked for future use, or sold or traded to other users. Most power plants that burn fossil fuels will need to obtain an adequate supply of allowances from the market of EPA-sponsored auctions to cover their future emissions. This article addresses the respective roles of regulators and the private sector in facilitating a market for SO{sub 2} emission allowances. In previous work, the authors have argued that state public utility commissions should seize the opportunity to encourage utilities to facilitate the allowance market. Yet it is the nature of new markets that many potential participants (including regulators) are risk-averse and wait for others to make the first move. Taken to the extreme, such behavior is a prescription for failure. The authors stated purpose is both to offer a perspective on how to make a market for what was previously considered an externality, as well as to stimulate debate among the various players and elicit better ideas. In fact, much more may be atmore » stake. The success or failure of the emissions trading program could well set a benchmark for future environmental protection efforts in the US and globally.« less