The list of most vulnerable hosts in your Classic VM Dashboard includes all hosts in your account with saved scan data. Hosts are listed by business risk and then by business impact so you can easily identify and fix the most critical hosts first.
Business Impact is the highest business impact level assigned to the host's asset groups. If the host is not included in any asset groups in your account, then a level of High (or its equivalent if customized) is used.
Security Risk is the highest severity level detected across vulnerabilities and potential vulnerabilities on the host.
Business Risk is expressed as a value (0 to 100). Generally, the higher the value the higher the potential for business loss since the service returns a higher value when critical assets are vulnerable. A Manager can configure business risk by going to Reports > Setup > Business Risk. (Express Lite users cannot edit the settings.)