Mitsui Steel Development Company Makes 20 Percent Equity Investment in Acero Prime

Acero Prime, the Mexican steel processing joint venture of Feralloy Mexico (a subsidiary of Feralloy Corporation - "Feralloy") and United States Steel Export Company de Mexico (a subsidiary of United States Steel International, Inc. (NYSE: X) - "USSEM"), are pleased to announce that Mitsui Steel Development Company, Inc. (a subsidiary of Mitsui & Co.(U.S.A.), Inc. - "Mitsui") has made a 20 percent equity investment in Acero Prime. Feralloy, the managing member, and USSEM will each own 40 percent.

Mitsui's participation will provide additional opportunities to more fully utilize the venture's facilities and increase sales in Mexico. Acero Prime, with headquarters in San Luis Potosi, also operates plants in Toluca and Ramos Arizpe. Their business is centered around servicing the automotive and appliance industries in Mexico with logistics services and processed flat rolled steel on a just-in-time basis.

SOURCE: Acero Prime

CONTACT: Roger Sippey of Feralloy Corporation, +1-773-380-1503; or John
Armstrong of United States Steel, +1-412-433-6792; or Nobuhiko Tomishima of
Mitsui Steel Development, +1-212-878-0942

Web site: http://www.ussteel.com/

Company News On-Call: http://www.prnewswire.com/comp/929150.html