Regardless of the conception of sustainability that we accept, it is accepted that transparency is at the core of the matter and, therefore, of its regulation. It is therefore appropriate to analyse its regulatory sources from the perspective of the insurance market, as well as to offer an analysis of the novelties it raises. This chapter therefore begins by examining in depth the hard and soft law instruments applicable to transparency in the insurance market. Afterwards, it examines those features that differentiate it from other reporting.