Yes, selling before maturity gets you the market price. So if you look at the latest auction results for a 91-Day bill, $10K in bills sold for about $9925. That a yield of approximately 3% ANNUALLY. 91-Days from now, they will mature at $10K. So essentially between now and then in theory there should be a gradual creep toward $10K. The problem is that short rates fluctuate to some degree, and therefore on a given day the market price could be a little less than you would expect had short term rates increased. But I think you can see that if you bought a 91-Day bill today, and sold it 45 days from now, the chances are high that you would receive more than you paid.
Now, the larger problem is that there is a service fee typically to sell the 91-day bills prior to maturity. So if you're dealing in small amounts this can be a bigger issue than the actual price that you receive. The service fee charged by the treasury is $45 I believe. It should be on the site.
For this reason, I think the best way to buy Bills is to buy some every week at the auction for 3 months, provided you have capital to do so. This way, as they begin to mature, you should have some maturing every week which you can then roll over into more bills, or which you can use for some other purpose if necessary. You probably would not need to sell them prior to maturity. Or alternatively, space them out further, say every month instead of every week.
OldTrader
