change in the market structure to address the underlying cause of the harm from the unilateral exercise of market power. They simply ask that the firm be a “good citizen” and not maximize profits.

For the case of the U.K., the MALC anticipated punishing those market participants that exercised significant amount unilateral market power. However, one difficulty with this approach is that the major beneficiaries of the unilateral exercise of market power are the firms that exercised little if any unilateral market power. One could therefore imagine some firms finding ways to compensate larger firms for exercising their unilateral market power so that all firms can reap benefits. A second difficulty is distinguishing the exercise of significant market power worthy of punishment from expected profit‐maximizing behavior. In testimony to the United Kingdom Competition Commission, Wolak (2000b) made these and a number of other arguments against the MALC, which the Commission eventually decided not to implement.

Another potential benefit associated with public data release is that it enables third‐ parties to undertake analyses of market performance. The US policies on data release severely limit the benefits from this aspect of a public data release policy. Releasing data with the identities of the market participant masked makes it impossible to definitively match data from other sources to specific market participants. For example, some market performance measures require matching data on unit‐level heat rates or input fuel prices obtained from other sources to specific generation units. Strictly speaking, this is impossible to do if the unit name or market participant name is not matched with the generation unit.

The long time lag between the date the data is produced and the date it is released also greatly limits the range of questions that can be addressed with this data. Taking the example of the California electricity crisis, by January 1, 2001, the date that masked data from June of 2000 was first made available to the public, the exercise of unilateral market power in California had already resulted in more than $5 billion in overpayments to suppliers in the California electricity market as measured by BBW (2002). Consequently, a long time lag between the date the data is produced and the date it is released to the public has an enormous potential cost to consumers that should be balanced against the benefits of delaying the data release.

The usual argument against immediate data release is that suppliers could use this information to coordinate their actions to raise market prices through sophisticated tacit collusion schemes. Although the immediate availability of information on bids, schedules and actual unit‐level production could allow suppliers to design more complex state‐ dependent strategies for enforcing collusive market outcomes, it is important to bear in mind that coordinated actions to raise market prices are illegal under US anti‐trust law and under the competition law in virtually all countries around the world. The immediate availability of this data means that the public also has access to this information and can undertake studies examining the extent to which market prices difference competitive benchmark levels as described in BBW (2002). Keeping this real‐time data confidential prevents this potentially important form of public scrutiny of market performance from occurring.

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