Which of the following statements regarding collateralized debt obligations $($CDOs$)$ is NOT accurate?

CDOs are the result of subdividing and recombining mortgage securities into different securities$.$

The complexity of CDOs made it difficult for investors to assess the aggregate risk of a particular CDO.

The process of creating CDOs reduced the overall risk embedded in securitized mortgages.

Each time a new security was created and rated, fees were being earned by investment banks and rating agencies.

None of these options is inaccurate.