In 2012, the NCUA reported nearly 1,500 federally insured credit unions had loan participations with total balances of nearly $13 billion.

That figure may be the result of credit unions using CUSOs to underwrite, document and service loans. CUSOs locate prospective borrowers through loan brokers then select a credit union to be the loan seller based on where the borrower is a member or would qualify for membership. 

Critics have argued that participations originated through loan brokers may pose some dangers. For one, if the loan is offered by a loan broker after it's been declined by local lenders and is then offered to an out-of-state credit union, it can put that buying credit union in a high-risk situation. Secondly, in some cases, these borrowers may be desperate and willing to pay fees that are twice or three times what a credit union would normally charge, critics have said.