DEFINITION of 'Intermarket Surveillance Information System - ISIS'
A publicly-accessible electronic database in which securities trade information is stored. The Intermarket Surveillance Information System contains data that includes the time of the trade and all participants involved. ISIS allows regulators to audit the trail of securities trades.
BREAKING DOWN 'Intermarket Surveillance Information System - ISIS'
The Intermarket Surveillance Information System was developed in order to counter the possibility of fraudulent trading, since a database open to the public sheds light on trades that may be spurious or based on insider information. Regulators are able to set up alarms that can be tripped if certain transactions occur relating to specific securities, and then audit the transaction trail in order to determine if something is amiss.