A flash report is a summary of the key operational and financial outcomes of a business. It is typically provided by the accounting department to the management team on a frequent basis, perhaps daily or weekly. The report is intended to point out issues that the management team can take action on. The information listed on the report will change over time, since some topics will be settled and no longer require attention, while new areas will crop up that need to be fixed. Literally anything can be listed on the report, such as bottleneck utilization, the status of overdue receivables, the customer order fulfillment rate, and the amount of storage space left in the warehouse.
The report is only circulated internally; it is not intended to be perused by outsiders, since it contains confidential information.