The OCC's quarterly report on trading revenues and bank derivatives activities is based on Call Report information provided by all insured U.S. commercial banks and trust companies, reports filed by U.S. financial holding companies, and other published data. The notional amount of derivatives held by insured U.S. commercial banks decreased $1.4 trillion, or 0.6%, from the second quarter of 2011 to $248 trillion. Notional derivatives are 5.7% higher than at the same time last year. Derivatives activity in the U.S. banking system continues to be dominated by a small group of large financial institutions. The five banks with the most derivatives activity hold 96% of all derivatives. Insured commercial banks have more limited legal authorities than do their holding companies.