Ernst & Young Global Limited, trading as EY, is a multinational professional services partnership. EY is one of the largest professional services networks in the world. Along with Deloitte, KPMG and PwC, it is one of the Big Four accounting firms. It primarily provides assurance, tax, information technology services (including managed services in areas like Cybersecurity, Cloud, Digital Transformation and AI), consulting, and advisory services to its clients.
https://en.wikipedia.org/wiki/Ernst_%26_Young