News Release

Exchange Increase Margins for Natural Gas Futures and Other Related Contracts

Mon Aug 29 2005

NEW YORK, N.Y., August 29, 2005 — The New York Mercantile Exchange, Inc., announced today it would change the margins for natural gas, Henry Hub swap, NYMEX miNYsm natural gas, Henry Hub swing swap and Henry Hub penultimate swap futures contracts at the close of business on August 29.

Margins on the first and second months of the natural gas futures contracts will increase to $10,000 from $8,000 for clearing members, to $11,000 from $8,800 for members, and to $13,500 from $10,800 for customers. The margins for the third to sixth months will increase to $9,750 from $7,750 for clearing members, to $10,725 from $8,525 for members, and to $13,163 from $10,463 for customers. The margins for the seventh to 19th months will increase to $5,000 from $4,000 for clearing members, to $5,500 from $4,400 for members, and to $6,750 from $5,400 for customers. The margins for all other months will remain the same.

Margins on the first and second months of the Henry Hub swap futures and the Henry Hub penultimate swap futures contracts will increase to $2,500 from $2,000 for clearing members, to $2,750 from $2,200 for members, and to $3,375 from $2,700 for customers. The margins on the third to sixth months will increase to $2,438 from $1,938 for clearing members, to $2,681 from $2,131 for members, and to $3,291 from $2,616 for customers. The margins for the seventh to 19th months will increase to 1,250 from $1,000 for clearing members, $1,375 from $1,100 for members, and to $1,688 from $1,350 for customers. All other months will remain the same.

The margins on the first and second months of the NYMEX miNYsm natural gas futures contracts will increase to $5,000 from $4,000 for clearing members, to $5,500 from $4,400 for members, and to $6,750 from $5,400 for customers.

The margins on the first month of the Henry Hub swing swap futures contracts will increase to $2,500 from $2,000 for clearing members, to $2,750 from $2,200 for members, and to $3,375 from $2,700 for customers.

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