Abstract: The system enables people who trade in stock listed securities to check whether a transaction is compliant with existing laws, rules and company regulations before an intended transaction is actually executed. An unambiguous ‘Yes or No’ will be provided regarding the question whether the intended transaction is compliant with existing laws, rules and company regulations. This answer is provided by a computer system that by means of a rules or decision engine running against a database with data on clients, rules, market news and other relevant data about the insider determines the correct answer whether a transaction will be compliant or not. This indication is therefor of a pre-trading nature.