Foreign banks were able to operate within the United States free of federal regulation until the International Banking Act of 1978 was passed. When enacted, the act limited foreign banks' geographic expansion and banking activities to similar U.S.-based banks and required foreign banks to carry adequate reserves. By the time the Federal Bank Supervision Enhancement Act was passed, more than 280 foreign banks were operating in the U.S., and held more than $626 billion in assets, or 18% of all banking assets in the U.S.