Very important factor is that the legislation is modern, flexible and well proven. Some jurisdictions have introduced new and modern suites of corporate legislation, in particular designed for international business whilst others have amended existing domestic legislation to cater for offshore requirements. That being said, for fairly many offshore jurisdictions the relevant pieces of legislation are basically carbon copies of each other. For example, quite a number of jurisdictions have taken the IBC Act of the British Virgin Islands and adapted it to their situation without much of a change. Quite often the legislation of relatively new offshore centres, such as, for example, Seychelles or Saint Lucia, tend to be very well thought out and put together, having taken care of all the shortfalls and errors of the earlier laws in other, more older offshore tax havens. All in all, if the total number of IBC`s registered in a certain country is in six figures or more (you can usually tell by the current registration numbers), it means that the system is working fairly well.
A successful offshore financial centre must besides have a reliable, independent judiciary system with a proven track record of defending offshore interests, especially against claims and requests originating from abroad.