Sweep Accounts Question:

Eurodollar sweeps are legal transfers of funds to the bank's offshore entities, although essentially they are just an accounting technique to allow the banks to have full lending of the funds without the reserve requirements normally required and without having to pay for FDIC insurance (as the sweep is uninsured). Essentially, the funds are just unsecured obligations of the bank, and therefore are paid the highest interest rate offered by the bank to overnight deposit borrowings.