One of the nice features of the USDi digital currency is that its path is known with certainty well in advance. The price of USDi is determined by the interpolated CPI index value compared with the value on the reference day (315.605). So, for example, we know that today’s[1] USDi value is 1.02681 because today’s CPI index value is 324.06614, and we know that because we know how to interpolate between the CPI prints from 3 months ago (324.122) and 2 months ago (324.054).
Importantly, those numbers we are interpolating between are the Non-seasonally-adjusted CPI figures from December (released in January) and January (released in February). And that interpolation methodology is exactly the methodology that TIPS use.[2]
You will notice that the CPI from 2 months ago is lower than the CPI from 3 months ago. That means that prices actually fell, before seasonal adjustment, which means that USDi actually declined slightly over the course of the month. It was even worse in January, because the November CPI was – as I have noted before – complete garbage due to the fact that BLS procedures led them to assume zero inflation for a lot of the missing October data. In the chart below, you can see the sharp correction during which USDi actually declined during January (and slightly further, in February).
Now, because we can ‘see the future’ due to the interpolation mechanism, we know exactly where USDi will trade each day in March. That’s also indicated on the chart. So we know that in March, USDi will rise at a 4.53% annualized pace. One-month t-bills are 3.6% right now. You do the math.
It gets better: the same BLS procedures that led to the terrible November number lead to self-correction, so the CPI Index will catch up over time. The biggest part of that catch-up is due to the rotation of the rent sample over 6 months, so while we do not know exactly what CPI will print at for February, March, April, and May, we have a good confidence that it will be above trend. We can see that from the CPI “fixings” market where those particular CPI prints trade. The market price is the market price, and sometimes wrong, but based on what trades in the market right now we can anticipate (orange line above) that USDi will climb at an annualized rate of 5.63% in April and 5.53% in May before slipping back to a still-better-than-bills 4.17% in June.
What does any of this have to do with duration?
Well, you may read this and say to yourself “I can get the same benefit if I just buy short TIPS bonds.” But no, you can’t. That’s because when you buy a TIPS bond, the principal amount rises with inflation but you still have to deal with price. It turns out that TIPS traders are very aware that their accretion (what we call the uplift in principal) is going to be higher than TBill rates over the next few months, and so the current price of TIPS bonds fully discount this. The July 2026 TIPS, which will mature at the CPI index value of July 15th (which is interpolated between April’s CPI and May’s CPI, so it includes all of those rebound months), trades at a price of 100-13…and remember, it matures at 100. So you’ll gain the accretion, but lose on price. I’ll save you the math: that price means the real yield of that bond is about -1%, which is convenient since the CPI between now and then is going to be something around 1% higher than the Tbill yield.
Every day that passes, as the principal value of the TIPS bond accretes, the price will decline. The only way you can profit versus fixed-rate Treasuries is if you are smarter than the market, and your forecast of CPI is better than what is already embedded in the price of the bond.
USDi has a price, but it is completely insensitive to yields which means you do not have to pay a premium to buy it now (nor did you get a discount back in December knowing the bad January numbers were coming). You can buy USDi today knowing that you will earn those exciting forthcoming CPI prints, without sacrificing principal.[3] You can buy USDi against USDC on Uniswap, or simply go to https://usdicoin.com/mint.
I’ve told you before how interesting USDi is since it’s the zero-duration instrument. Here is another concrete example.
[1] I say “today’s” because I am illustrating all of this with daily interpolation, but in practice USDi interpolates every block or “hash,” which is just a few seconds in length.
[2] …except for the fact that TIPS interpolate daily and USDi almost continuously.
[3] Of course, this is not investment advice. Although it sure sounds like it. Do your homework!
