ONEX GROUP to receive an additional US$87 MILLION in spirit aerosystems secondary offering

TORONTO and NEW YORK — Onex Corporation (TSX: OCX) announced today that the underwriters of the secondary offering of shares of Spirit AeroSystems Holdings, Inc. (NYSE: SPR) have exercised approximately 90% of their over-allotment option to acquire an additional 2.8 million shares of class A common stock at the offering price of US$33.50 per share. Onex had previously announced Spirit AeroSystems’ intention to complete a secondary offering of 31.5 million shares. This offering closed on May 25, 2007. The exercise of the over-allotment option will result in an aggregate offering of 34.3 million shares being offered by selling stockholders, including Onex, for gross proceeds of US$1.15 billion.

Following the secondary offering and the exercise of the over-allotment option, Onex and its co-investors continue to hold 32.4 million shares of Spirit AeroSystems’ common stock valued at US$1.09 billion at the offering price. This brings the total proceeds realized to date by Onex and its co-investors on Spirit AeroSystems to approximately US$2.3 billion.

A registration statement relating to these securities was declared effective by the United States Securities and Exchange Commission on May 21, 2007. This communication shall not constitute an offer to sell or a solicitation of an offer to buy, nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. A final written prospectus relating to the offering may be obtained from: Credit Suisse Prospectus Department, One Madison Avenue, New York, NY 10010, tel: +1-212-325-2580; Goldman, Sachs & Co., Attn: Prospectus Dept., 85 Broad Street, New York, NY 10004; fax: +1-212-902-9316, or email at prospectus-ny@ny.email.gs.com; Morgan Stanley, 180 Varick Street, Second Floor, New York, NY 10014/ Attn: Prospectus Department, or email at prospectus@morganstanley.com.

Onex makes private equity investments through the Onex Partners and ONCAP family of Funds. Through these Funds, which have third-party capital as well as Onex’ capital, Onex generates annual management fee income from third-party capital and is entitled to a carried interest on that capital. The third-party capital under management currently has a value of approximately $5 billion. Onex also has a Real Estate Fund and a Public Markets Fund.

Onex’ operating companies have annual revenues of $28 billion, assets of $28 billion and 184,000 employees worldwide. These companies are in a variety of industries, including electronics manufacturing services, aerostructures manufacturing, healthcare, financial services, aircraft & aftermarket, metal services, customer management services, theatre exhibition, personal care products and communications infrastructure.