News Release

NYMEX to Change Margins for Electricity Futures Contracts on NYMEX ClearPort®

Wed Jun 18 2008

New York, N.Y., June 18, 2008 -- The New York Mercantile Exchange, Inc. today announced margin changes for some of its electricity futures contracts on NYMEX ClearPort, beginning at the close of business tomorrow.

The margins for the first month of the NYISO Zone A 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 the second to sixth months will increase to $4,000 from $3,500 for clearing members, to $4,400 from $3,850 for members, and to $5,400 from $4,725 for customers. Margins for all other months will remain unchanged.

The margins for the first month of the NYISO Zone G peak electricity futures contract will increase to $8,000 from $4,000 for clearing members, to $8,800 from $4,400 for members, and to $10,800 from $5,400 for customers. Margins for the second to sixth months will increase to $5,500 from $4,500 for clearing members, to $6,050 from $4,950 for members, and to $7,425 from $6,075 for customers. Margins for all other months will remain unchanged.

The margins for the first month of the NYISO Zone J peak electricity futures contract will increase to $9,000 from $4,000 for clearing members, to $9,900 from $4,400 for members, and to $12,150 from $5,400 for customers. Margins for the second to sixth months will increase to $5,000 from $4,500 for clearing members, to $5,500 from $4,950 for members, and to $6,750 from $6,075 for customers. Margins for all other months will remain unchanged.

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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: Anu Ahluwalia, 212-299-2439 or Brenda Guzman, 212-299-2436

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