The banking industry's extensive reliance on air transportation was underscored in the aftermath of the September 11 tragedy, when air transportation came to a standstill and the flow of checks slowed dramatically. During the week of the attacks, the Federal Reserve Banks' daily check float, which is normally a few hundred million dollars, ballooned to more than $ billion.
Similarly, interference in the managerial functions of one entity by the officials of another has also been witnessed. Increasing complexities in the ownership and managerial structure of a group can make the supervision of financial institutions in the group difficult.