Fitch Ratings Upgrades Two Classes of Porter Square CDO I, Ltd.

NEW YORK -- Fitch Ratings upgrades two classes and affirms three classes of notes issued by Porter Square CDO I, Ltd. (Porter Square I). The following rating actions are effective immediately:

--$146,468,614 class A-1 notes affirmed at 'AAA';

--$78,000,000 class A-2 notes affirmed at 'AAA';

--$26,000,000 class A-3 notes affirmed at 'AAA';

--$24,000,000 class B notes upgraded to 'AA+' from 'AA';

--$16,000,000 class C notes upgraded to 'BBB+' from 'BBB'.

Porter Square I is a collateralized debt obligation (CDO) managed by TCW Asset Management Company (TCW), which closed July 31, 2003. Porter Square I is composed of 49.15% residential mortgage-backed securities (RMBS), 42.52% CDOs, 4.48% commercial mortgage-backed securities (CMBS), 3.14% asset-backed securities (ABS), and 0.70% synthetic securities.

Since the last review on Sept. 14, 2004, the collateral has continued to perform. The weighted average rating factor (WARF) remained constant at 11 ('BBB+/BBB') as of the most recent trustee report dated June 30, 2005 versus a test trigger of 15 ('BBB/BBB-'). The class A/B overcollateralization (OC) ratio increased from 109.29% to 111.39% versus a test trigger of 105.75%. The class C OC ratio increased from 104.36% to 105.25% versus a test trigger of 102.00%. The class A/B interest coverage ratio is passing at 137.72% with a trigger of 110.00%. The class C interest coverage ratio is also passing at 151.26% with a trigger of 105.00%. Additionally, since closing the class A-1 notes have redeemed approximately 38.97% of the original balance.

The rating of the class A-1, A-2, and A-3 notes addresses the likelihood that investors will receive full and timely payments of interest, as per the governing documents, as well as the stated balance of principal by the legal final maturity date. The ratings of the class B and class C notes addresses the likelihood that investors will receive ultimate and compensating interest payments, as per the governing documents, as well as the stated balance of principal by the legal final maturity date.

Fitch will continue to monitor and review this transaction for future rating adjustments. Additional deal information and historical data are available on the Fitch Ratings web site at www.fitchratings.com. For more information on the Fitch VECTOR Model, see 'Global Rating Criteria for Collateralized Debt Obligations,' dated Sept. 13, 2004, also available at www.fitchratings.com.

Fitch's rating definitions are available on the agency's public web site, www.fitchratings.com. Published ratings, criteria and methodologies and relevant policies and procedures are also available from this site, at all times. This document will remain on the public site for seven days.