52-Week T-Bill Rolling Ladder Question

[early-morning]

I want to buy a 52-week T-Bill every month for 12 months. Assuming I buy the first bill in Jan 2017, I would want to buy another bill with the proceeds of the first bill in Jan 2018. However, according to my calculations the first bill will not mature in time for the Jan 2018 auction date. Assuming the auction occurs every 4 weeks I calculate the dates as follows:

Jan 2017 T-Bill auction - 2/28/17
Jan 2017 T-Bill matures - 3/1/18
Jan 2018 T-Bill auction - 2/27/18

The Jan 2017 bill matures 2 days after the Jan 2018 auction.

I'd have to wait a month for the next auction to re-invest the proceeds.

I'm trying to figure out how to keep that money invested at all times. I like the ladder concept just in case I need the cash, I know I'll have a payment coming every month. I'm at Vanguard.

 

[GrayHare]

One way is to buy 13-months worth, then each month sit on the cash for the 3+ weeks until the next auction. It's not like short-term T-bills are paying much more interest than a money market account.