News Release

NYMEX to Change Margins for Financially Settled Electricity Futures Contracts

Tue Jul 18 2006

NEW YORK, NY, July 18, 2006 — The New York Mercantile Exchange, Inc. today announced margin changes for its Northern Illinois hub peak, Northern Illinois hub off peak, AEP-Dayton hub peak, AEP–Dayton hub off peak, and PJM financially settled peak monthly electricity futures contracts on NYMEX ClearPort®, beginning at the close of business on July 19.

Margins for the first month of Northern Illinois hub peak electricity futures contract will increase to $6,000 from $5,500 for clearing members, to $6,600 from $6,050 for members, and to $8,100 from $7,425 for customers. The margins for all other months will remain the same.

The margins for the first month of Northern Illinois hub off peak electricity futures contract will increase to $6,000 from $5,000 for clearing members, to $6,600 from $5,500 for members, and to $8,100 from $6,750 for customers. Margins for all other months will remain the same.

Margins for the first month of AEP-Dayton hub peak electricity futures contract will increase to $7,000 from $6,500 for clearing members, to $7,700 from $7,150 for members, and to $9,450 from $8,775 for customers. The margins for all other months will remain the same.

The margins for the first month of AEP-Dayton hub off peak electricity futures contract will increase to $4,000 from $3,000 for clearing members, to $4,400 from $3,300 for members, and to $5,400 from $4,050 for customers. Margins for all other months will remain the same.

Margins for the first month of PJM financially settled peak monthly electricity futures contract will increase to $9,000 from $8,500 for clearing members, to $9,900 from $9,350 for members, and to $12,150 from $11,475 for customers. The margins for the second to 12th months will remain the same. Margins for the 13th to 16th months will increase to $3,500 from $3,000 for clearing members, to $3,850 from $3,300 for members, and to $4,725 from $4,050 for customers. The margins for all other months will remain the same.

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Forward Looking and Cautionary Statements
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.

Contact: Brenda Guzman, 212-299-2436

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