RE: SLM Corporation (“SLM/SLM1C”) Proposed Merger
with Mustang Holding Company Inc.

Shareholders of SLM Corporation (“SLM/SLM1C”) will vote on Wednesday, August 15, 2007 to approve a proposed Merger between SLM and Mustang Merger Sub, Inc., a wholly owned subsidiary of Mustang Holding Company Inc., an entity owned by an investor group consisting of affiliates of J.C. Flowers & Co. LLC and each of JPMorgan Chase Bank, N.A. and Bank of America, N.A. The Merger is expected to become effective on a date to be announced. Pursuant to the current understanding of the terms of the proposed merger, each share of SLM Common Stock outstanding immediately prior to the consummation of the Merger will be converted into the right to receive $60.00 cash, without interest, per SLM share.

THE FOREGOING IS AN UNOFFICIAL SUMMARY OF THE TERMS OF THE MERGER, PREPARED BY ONECHICAGO FOR THE CONVENIENCE OF ITS MEMBERS. ONECHICAGO ACCEPTS NO RESPONSIBILITY FOR THE ACCURACY OR COMPLETENESS OF THE SUMMARY. MEMBERS SHOULD REFER TO THE SLM CORPORATION AND MUSTANG HOLDING COMPANY INC. JOINT PROXY STATEMENT/PROSPECTUS DATED JULY 18, 2007, FOR THE AUTHORITATIVE DESCRIPTION OF THE MERGER AND ALL OF ITS TERMS AND CONDITIONS.

SLM1C Contract Adjustment

Pursuant to The Options Clearing Corp. rules, all outstanding SLM1C future contracts will be adjusted as follows. On the business day immediately following the effective date of the merger all SLM Corporation future contracts will require the delivery or receipt of: $6,000.00 in cash. Expiry of all SLM1C future contacts will be accelerated. The SLM1C futures symbol will remain the same.
Trading in SLM1C futures will cease as of the close of business on the effective date of the merger.