The Washington Pooling and Servicing Agreement (PSA) is a legal contract that outlines the terms and conditions for the pooling and servicing of mortgage loans between Credit Suisse First Boston Mortgage Securities Corp., Washington Mutual Bank F.A., and Bank One. This agreement is essential in the mortgage-backed securities (MBS) market, providing a framework for the securitization and management of mortgage loans. The PSA governs the relationship among these entities and sets forth the rights and responsibilities of each party involved. It establishes the rules for the pooling of mortgage loans into a mortgage-backed security and governs the activities related to the servicing and management of these loans. The agreement entails specifics like the servicing agent, payment processes, handling of borrower defaults, and reporting requirements. In the case of specific types of Washington Pooling and Servicing Agreements involving Credit Suisse First Boston Mortgage Securities Corp., Washington Mutual Bank F.A., and Bank One, the following variations are observed: 1. Standard PSA: This refers to the typical agreement when mortgage loans are pooled and securitized by the mentioned entities. It follows the standard template of the Washington Pooling and Servicing Agreement. 2. Subservicing PSA: This type of agreement comes into play when one entity delegates the servicing responsibilities to another party. For instance, if Bank One acts as a subscriber, it will handle the day-to-day management of the mortgage loans on behalf of Credit Suisse First Boston Mortgage Securities Corp. and Washington Mutual Bank F.A. 3. Master PSA: A Master Pooling and Servicing Agreement is established when multiple SAS are consolidated into a single, comprehensive agreement. This allows for more streamlined management and coordination of mortgage-backed securities transactions involving Credit Suisse First Boston Mortgage Securities Corp., Washington Mutual Bank F.A., and Bank One. The Washington Pooling and Servicing Agreement between Credit Suisse First Boston Mortgage Securities Corp., Washington Mutual Bank F.A., and Bank One is crucial in facilitating the securitization and management of mortgage loans. It ensures that the interests of all parties involved are protected and provides clarity on the processes and responsibilities related to the pooling and servicing of these loans.