The originate-to-distribute model seems to have contributed to the loosening of underwriting standards in 2005 and 2006.

NPR: Transcript: Bernanke on Mortgages, Foreclosures

This "originate-to-distribute" model gave lenders (and, thus, mortgage borrowers) greater access to capital markets, lowered transaction costs, and allowed risk to be shared more widely.

NPR: Transcript: Bernanke on Mortgages, Foreclosures