Both GAAP & IFRS are based on a conceptual framework. Fundamentals difference between US GAAp & IFRS is that IFRS tends to be less detailed in its reporting disclosure requirements than GAAP. In other words IFRSs are “principles-based” standards while US GAAP are “rules-based” standards. Further, transaction analysis is similar under both IFRS and GAAP but different standards may impact how transactions are being recorded.