Why was IOSCO's endorsement of IAS so important to the IASC's efforts? Multiple Choice OSCO triggered the reaction of the FASB for adoption of us in the USA N OVA IOSCO the wonderd setter body of the European Union 0 IOSCO mandated the use of IAS in more than 150 countries 0 Oscos endorsement of AS legitimized the ASCs calm as the international accounting standard setter and helped to address the lack of enforcement