The term INFORMS ON can be solved by the crossword solutions RATS and TURNSIN. RATS is an acronym for 'Reporting of Actual Transactions to Supervisors' and is a system used by the Financial Industry Regulatory Authority (FINRA) to monitor the activities of brokers and dealers. TURNSIN is an acronym for 'Tipping Unregistered Persons to Register as Securities Industry Professionals' and is a program that encourages unregistered persons to become registered securities industry professionals.