-- Iridium Expects Full-Year 2009 Operational EBITDA of $120- 130 million, Up 11 to 20% Over 2008, Reflecting Continued Strength of the Business in the Face of Weak Global Economy

NEW YORK and BETHESDA, Md., April 28 /PRNewswire-FirstCall/ -- GHL Acquisition Corp. (NYX: GHQ) ("GHL Acquisition") and Iridium Holdings LLC ("Iridium" or the "Company"), a leading provider of voice and data mobile satellite services, today jointly announced the signing of an amendment to the definitive agreement under which they plan to combine. Under the terms of the amendment, the aggregate consideration payable by GHL Acquisition to Iridium's existing shareholders will be reduced by 15%, a reflection of the changes in market valuation levels since the transaction was announced in September 2008. The amended agreement, unanimously approved by the Board of Directors of GHL Acquisition and Iridium as well as Iridium's major shareholders, values Iridium at an enterprise value of approximately $517.3 million(i).

Scott L. Bok, Chief Executive Officer of GHL Acquisition, said: "We continue to believe Iridium will be a great investment for us, and the Company's guidance today makes clear that the price reduction is a function of lower equity market valuations rather than any disappointments relative to the Company's strong record of growth and profitability. The new purchase price negotiated with Iridium's current shareholders takes into consideration the decline in global markets since the transaction was announced in September 2008, and allows the Company to retain a slightly larger cash balance post-transaction, reflecting both lower equity market valuations generally and our desire to reduce the Company's needs for future outside financing. With the amendments to our transaction agreement announced today, we believe the pro forma fully distributed valuation of our combined company is even more attractive relative to Iridium's closest comparables."

Matt Desch, Chief Executive Officer of Iridium, said: "Considering the current economic backdrop, Iridium's growth and profitability are a testament to the Company's business model and mission-critical position with its customers. We anticipate that our subscriber base will experience growth of approximately 20% this year. We also anticipate strong growth in commercial and government service revenues that will be partially offset by a decline in equipment sales, resulting in total revenue growth in the low single digits over the full year 2008. This, combined with our largely fixed cost business model, is expected to result in Operational EBITDA for the full year 2009 of between $120 and $130 million, implying a growth rate of between 11% and 20% over the full year 2008. With these strong results and the amendments to the transaction agreement announced today, we believe Iridium is better positioned than ever to complete the planned transaction and continue its impressive growth trajectory."

Separately, Greenhill & Co. agreed to forfeit 2.0 million additional warrants purchased by it from GHL Acquisition in a private placement concurrently with GHL Acquisition's IPO. In addition, GHL Acquisition has withdrawn its plan to launch a tender offer for GHL Acquisition shares concurrent with closing of the combination with Iridium.

Details of the Amended Transaction

Under amended terms of the transaction:

-- The transaction values Iridium at an enterprise value of approximately

$517.3 million(i).

-- Current shareholders of Iridium will receive $77.1 million of cash and

approximately 29.4 million common shares upon completion of the

transaction. Additionally, after closing of the transaction, current

shareholders of Iridium will receive a $25.5 million payment for

facilitating a step-up in the tax basis of Iridium's assets,

resulting in future tax savings for the Company.

-- Remaining cash held in trust will be available to retire Iridium's

current net indebtedness of approximately $145.8 million, pay

transaction-related expenses including deferred compensation to GHL

Acquisition's underwriters, and be used by Iridium for general

corporate purposes and capital expenditures.

-- Greenhill & Co.'s $22.9 million pre-completion investment in

Iridium will be convertible into approximately 1.9 million GHL

Acquisition shares.

-- Post-transaction and after the Greenhill & Co. forfeitures described

below, GHL Acquisition will have approximately 78.4 million shares and

44.1 million warrants outstanding, assuming no GHL Acquisition public

shareholders vote against the transaction and elect conversion. In the

case that 30% of GHL Acquisition's current public shareholders vote

against the transaction and elect conversion, approximately 68.4 million

shares and 44.1 million warrants will be outstanding.

Completion of the transaction is subject to Federal Communications Commission approval, GHL Acquisition stockholder approval and other customary closing conditions, and is expected to occur this summer.

Securities Forfeitures by Greenhill & Co.

Effective upon completion of the transaction, Greenhill & Co. has agreed to forfeit the following GHL Acquisition securities which it currently owns: (1) 1,441,176 common shares; (2) 8,369,563 founder warrants; and (3) 4,000,000 private placement warrants. These forfeitures will reduce the combined company's shares and warrants outstanding immediately post-closing.