RE: Archstone-Smith Trust (“ASN/ASN1C”) Proposed Merger
with River Holding, LP

Shareholders of Archstone-Smith Trust (“ASN/ASN1C”) will vote on Tuesday, August 21, 2007 to approve a proposed Merger between ASN and River Holding, LP, an entity jointly controlled by affiliates of Tishman Speyer Real Estate Venture VII, L.P. and Lehman Brothers Holdings Inc. The Merger is expected to become effective during the third quarter of 2007. Pursuant to the current understanding of the terms of the proposed merger, each share of ASN Common Stock outstanding immediately prior to the consummation of the Merger will be converted into the right to receive $60.75 cash, without interest, per ASN 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 ARCHSTONE-SMITH TRUST AND RIVER HOLDING, LP JOINT PROXY STATEMENT/PROSPECTUS DATED JULY 12, 2007, FOR THE AUTHORITATIVE DESCRIPTION OF THE MERGER AND ALL OF ITS TERMS AND CONDITIONS.

ASN1C Contract Adjustment

Pursuant to The Options Clearing Corp. rules, all outstanding ASN1C future contracts will be adjusted as follows. On the business day immediately following the effective date of the merger all Archstone-Smith Trust future contracts will require the delivery or receipt of: $6,075.00 in cash. Expiry of all ASN1C future contacts will be accelerated. The ASN1C futures symbol will remain the same.
Trading in ASN1C futures will cease as of the close of business on the effective date of the merger.