A form of collateralized debt obligation (CDO) that invests in credit default swaps (CDSs) or other non-cash assets to gain exposure to a portfolio of fixed income assets. Synthetic CDOs are typically divided into credit tranches based on the level of credit risk assumed. Initial investments into the CDO are made by the lower tranches, while the senior tranches may not have to make an initial investment. 

All tranches will receive periodic payments based on the cash flows from the credit default swaps. If a credit event occurs in the fixed income portfolio, the synthetic CDO and its investors become responsible for the losses, starting from the lowest rated tranches and working its way up. 



|||Synthetic CDOs are a modern advance in structured finance that can offer extremely high yields to investors. However, investors can be on the hook for much more than their initial investments if several credit events occur in the reference portfolio. 

Synthetic CDOs were first created in the late 1990s as a way for large holders of commercial loans to protect their balance sheets without actually selling the loans and potentially harming client relationships. They have become increasingly popular because they tend to have shorter life spans than cash flow CDOs and there is no extended ramp-up period for earnings investment. Synthetic CDOs are also highly customizable between the underwriter and investors.