To ensure a market for the AAA-rated super-senior tranches, another set of special
entities (known as structured investment vehicles or SIVs) was created to act as buyers of the
senior securities of the collateralized mortgage obligations. These entities financed the purchase
of structured assets (e.g., securitized credit card receivables or automobile loans, but
predominantly collateralized mortgage obligations) through the issue of short-term, asset-backed
commercial paper and medium-term investment notes, as well as subordinated capital. The same
process of overcollateralization and subordination of tranches that was used for CMOs was used
in creating these structures.