News Release

Exchange to Increase Margins for PJM Monthly LMP Electricity Contracts

Wed Aug 10 2005

NEW YORK, N.Y., August 10, 2005 — The New York Mercantile Exchange, Inc., announced today that it would increase the margins for its August 2005 PJM monthly electricity futures contract as of the close of business tomorrow.

Margins will increase to $5,000 from $3,500 for clearing members, to $5,500 from $3,850 to members, and to $6,750 from $4,725 for customers.

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This press release may contain forward–looking statements within the meaning of the Private Securities Litigation Reform Act, with respect to our future performance, operating results, strategy, and other future events. Such statements generally include words such as could, can, anticipate, believe, expect, seek, pursue, and similar words and terms, in connection with any discussion of future results. Forward–looking statements involve a number of assumptions, risks, and uncertainties, any of which may cause actual results to differ materially from the anticipated, estimated, or projected results referenced in forward–looking statements. In particular, the forward–looking statements of NYMEX Holdings, Inc., and its subsidiaries are subject to the following risks and uncertainties: the success and timing of new futures contracts and products; changes in political, economic, or industry conditions; the unfavorable resolution of material legal proceedings; the impact and timing of technological changes and the adequacy of intellectual property protection; the impact of legislative and regulatory actions, including without limitation, actions by the Commodity Futures Trading Commission; and terrorist activities and international hostilities, which may affect the general economy as well as oil and other commodity markets. We assume no obligation to update or supplement our forward–looking statements.

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