People and institutions who have LARGE amounts of cash are looking for a safe place to put it - banks are only FDIC insured up to $250,000, and unless there's some further action, the FDIC limit drops back to $100,000 on Jan 1, 2010.
So if you're looking for a place to sock away a couple of million dollars, SAFETY is more important right now than return.
I understand 4-week yields are now at zero, and 3-month T-bills are paying 0.005% . . . 6-month bills are at 0.3%. I know people who've kept money in T-bills for years, rolling them over every 6 months. Now as they mature these same people are now putting the money in banks, being sure to keep under the FDIC limit at any one bank.
3% - 4% interest is better than 0.3%.