13 C.F.R. § 120.1707
The Seller must retain a 15% or greater Loan Interest in each of its loans included in a Pool. At Pool formation, the CSA will issue the Seller a Seller Receipt evidencing the Seller's retained ownership in the Pool Loan. With SBA's written permission, the Seller may sell the Seller Receipt and Servicing Retention Amount in whole, but not in part, to a single entity at one time. The Seller may not sell less than 100% of the Seller Receipt and Servicing Retention Amount, and may not sell a participation interest in any portion of any of its Pooled loans. In addition, in order to complete such sale, Seller must have the purchaser of its rights to the Pool Loan execute an allonge to the Seller's First Lien Position 504 Loan Pool Guarantee Agreement in a form acceptable to SBA, acknowledging and accepting all terms of the Seller's First Lien Position 504 Loan Pool Guarantee Agreement, and deliver the executed original allonge and a copy of the corresponding First Lien Position 504 Loan Pool Guarantee Agreement to the CSA. All Pool Loan payments related to a Seller Receipt and Servicing Retention Amount proposed for sale will be withheld by the CSA pending SBA acknowledgement of receipt of all executed documents required to complete the transfer.
13 C.F.R. §120.1707