The "Challenge this Company" feature allows you to request assignment of an open account to one of your protected account categories. This is used when you identify a company you want to pursue and need to establish account ownership in the system.
Challenging a company ensures you're recognized as the point person for that prospect, giving you the ability to add pending dollars and log activity while awaiting managerial approval. It helps prevent account conflicts and secures your right to work that lead as part of your active pipeline.