News Release

NYMEX to Change Margins for Financially Settled Electricity Futures Contracts

Thu Oct 05 2006

New York, N.Y., October 5, 2006 — The New York Mercantile Exchange, Inc. today announced margin changes for some of its financially settled electricity futures contracts on NYMEX ClearPort®, beginning at the close of business tomorrow.

Margins for the first month of the Dow Jones North Path- 15 and Dow Jones South Path- 15 index swap electricity futures contracts will decrease to $12,000 from $17,000 for clearing members, to $13,200 from $18,700 for members, and to $16,200 from $22,950 for customers. The margins for the second to sixth months will decrease to $11,000 from $13,000 for clearing members, to $12,100 from $14,300 for members, and to $14,850 from $17,550 for customers. Margins for the seventh to 11th months will decrease to $6,000 from $7,500 for clearing members, to $6,600 from $8,250 for members, and to $8,100 from $10,125 for customers. The margins for all other months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers.

The margins for the first month of the Dow Jones Mid-Columbia and Dow Jones Palo Verde index swap electricity futures contracts will decrease to $12,000 from $15,000 for clearing members, to $13,200 from $16,500 for members, and to $16,200 from $20,250 for customers. Margins for the second to sixth months will decrease to $11,000 from $13,000 for clearing members, to $12,100 from $14,300 for members, and to $14,850 from $17,550 for customers. The margins for the seventh to 11th months will decrease to $6,000 from $7,500 for clearing members, to $6,600 from $8,250 for members, and to $8,100 from $10,125 for customers. Margins for all other months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers.

Margins for the first month of the Cinergy Hub LMP off-peak electricity futures contract will decrease to $2,500 from $3,500 for clearing members, to $2,750 from $3,850 for members, and to $3,375 from $4,725 for customers. The margins for the second to sixth months 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 seventh to 11th months will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers. The margins for all other months will remain the same.

Margins for the Michigan Hub LMP peak electricity futures contract will increase to $6,000 from $4,000 for clearing members, to $6,600 from $4,400 for members, and to $8,100 from $5,400 for customers.

The margins for the Michigan Hub LMP off-peak electricity futures contract will decrease to $3,000 from $4,000 for clearing members, to $3,300 from $4,400 for members, and to $4,050 from $5,400 for customers.

Margins for the MISO Illinois LMP peak electricity futures contract will decrease to $4,000 from $5,500 for clearing members, to $4,400 from $6,050 for members, and to $5,400 from $7,425 for customers.

Margins for the first month of the PJM Western Hub LMP monthly peak electricity futures contract will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. Margins for the second to fourth months will decrease to $5,000 from $7,000 for clearing members, to $5,500 from $7,700 for members, and to $6,750 from $9,450 for customers. Margins for the fifth and sixth months 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 seventh and eighth months will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers. Margins for the ninth to 12th months will decrease to $3,000 from $4,000 for clearing members, to $3,300 from $4,400 for members, and to $4,050 from $5,400 for customers. Margins for all other months will remain unchanged.

The margins for the first month of the PJM Western Hub LMP monthly off-peak and NYISO Zone A off-peak electricity futures contracts will remain the same. Margins for the second to sixth months will decrease to $7,000 from $8,000 for clearing members, to $7,700 from $8,800 for members, and to $9,450 from $10,800 for customers. Margins for all other months will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers.

Margins for the first month of the NYISO Zone A peak and NYISO Zone G peak electricity futures contracts will decrease to $3,500 from $4,500 for clearing members, to $3,850 from $4,950 for members, and to $4,725 from $6,075 for customers. The margins for the second to sixth months will decrease to $3,000 from $3,500 for clearing members, to $3,300 from $3,850 for members, and to $4,050 from $4,725 for customers. Margins for the seventh to 11th months will decrease to $3,000 from $4,000 for clearing members, to $3,300 from $4,400 for members, and to $4,050 from $5,400 for customers. The margins for all other months will remain the same.

The margins for the first month of the NYISO Zone G off-peak electricity futures contract will remain the same. Margins for the second to sixth months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. The margins for all other months will decrease to $3,000 from $5,000 for clearing members, to $3,300 from $5,500 for members, and to $4,050 from $6,750 for customers.

Margins for the first month of the NYISO Zone J peak electricity futures contract will remain the same. Margins for the second to sixth months will decrease to $3,000 from $3,500 for clearing members, to $3,300 from $3,850 for members, and to $4,050 from $4,725 for customers. The margins for all other months will decrease to $3,000 from $5,000 for clearing members, to $3,300 from $5,500 for members, and to $4,050 from $6,750 for customers.

The margins for the first month of the NYISO Zone J off-peak electricity futures contract will increase to $7,000 from $5,000 for clearing members, to $7,700 from $5,500 for members, and to $9,450 from $6,750 for customers. Margins for the second to sixth months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. The margins for all other months will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers.

Margins for the first month of the ISO New England Internal Hub peak electricity futures contract will decrease to $7,000 from $10,000 for clearing members, to $7,700 from $11,000 for members, and to $9,450 from $13,500 for customers. The margins for all other months will remain the same.

The margins for the first month of the ISO New England Internal Hub off-peak electricity futures contract will decrease to $5,000 from $7,000 for clearing members, to $5,500 from $7,700 for members, and to $6,750 from $9,450 for customers. Margins for the second to sixth months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. The margins for all other months will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers.

Margins for the first month to sixth months of the Northern Illinois Hub peak electricity futures contracts will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. The margins for all other months will decrease to $3,000 from $3,500 for clearing members, to $3,300 from $3,850 for members, and to $4,050 from $4,725 for customers.

The margins for the first month of the Northern Illinois Hub off-peak electricity futures contract will decrease to $4,000 from $5,000 for clearing members, to $4,400 from $5,500 for members, and to $5,400 from $6,750 for customers. Margins for the second to sixth months will remain unchanged. Margins for the seventh to 11th months will increase to $3,000 from $2,000 for clearing members, to $3,300 from $2,200 for members, and to $4,050 from $2,700 for customers. The margins for all other months will remain the same.

Margins for the first month of the AEP-Dayton Hub peak electricity futures contracts will decrease to $6,000 from $7,000 for clearing members, to $6,600 from $7,700 for members, and to $8,100 from $9,450 for customers. The margins for the second to sixth months will decrease to $6,000 from $8,000 for clearing members, to $6,600 from $8,800 for members, and to $8,100 from $10,800 for customers. Margins for the seventh to 11th 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. The margins for all other months will increase to $3,000 from $2,000 for clearing members, to $3,300 from $2,200 for members, and to $4,050 from $2,700 for customers.

The margins for the first month of the AEP-Dayton Hub off-peak electricity futures contract will decrease to $3,000 from $4,000 for clearing members, to $3,300 from $4,400 for members, and to $4,050 from $5,400 for customers. Margins for the second to sixth months will remain unchanged. Margins for the seventh to 11th months will decrease to $3,000 from $3,500 for clearing members, to $3,300 from $3,850 for members, and to $4,050 from $4,725 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.

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