Searches on that go back many years. The information is overused without thinking about it because percentage values are date (economy) dependent. The term T-Bill is often misused. The users often don't know the difference between a T-Bill and a Treasury Bond.
A Treasury Bill (T-Bill) is a short-term debt obligation backed by the U.S. government with a maturity of less than one year, sold in denominations of $1,000 up to a maximum purchase of $5 million.
Currently, all Treasuries having maturities less than 1-year (AKA T-Bills) have yields less than about 1% depending on maturity. One has to go all the way up to a 7-year Note to get 2.32%. So, exactly how does one get more than 3% below that? Even Buffett can't do that.
The following link (to an interactive chart) is very useful for a stock investor. Why? Because virtually all recessions can be accurately predicted when there is a rate inversion -- meaning short rates pay more than long rates. That happens when the Fed puts the brakes on the economy.
There are instructions at the site. You can grab the left vertical axis of the $SPX chart with the left button of your mouse, at which time the axis turns red; then while still holding the button down, drag the mouse across the chart to select dates. You will see how rates are distributed versus their maturity dates as you slide the mouse back and forth.
News 
Market Data 
Discover 
