One of the questions I was asked on Twitter last night was how to spot a tax haven. There is no easy answer to this. One way is to decide for yourself after reading the book Ronen Palan, Christian Chavagneux and I wrote on the subject. This is now a little out of date but available in many languages. The Korean version is just out.
Alternatively, there is this paper I wrote that remains one of the more important I have produced, in my opinion, admittedly.
And there is the whole Financial Secrecy Index.
But if you want a short version tax havens are secrecy jurisdictions and these are defined by me as places that intentionally create regulation for the primary benefit and use of those not resident in their geographical domain. That regulation is designed to undermine the legislation or regulation of another jurisdiction. To facilitate its use secrecy jurisdictions also create a deliberate, legally backed veil of secrecy that ensures that those from outside the jurisdiction making use of its regulation cannot be identified to be doing so.