Archive
The Fault, Dear Brutus, is in R*
I want to say something briefly about the “neutral rate of interest,” which has recently become grist for financial television because of new Trump-appointed Fed Governor Stephen Miran’s speech a couple of days ago in which he opined that the neutral rate of interest is much lower than the Fed believes it is, and that therefore the Fed funds target should be more like 2%-2.25% right now instead of 4.25%.
Cue the usual media clowns screaming that this is evidence of how Trump appointees do not properly respect the academic work of their presumed betters.
If that was all this is, then I would wholeheartedly support Miran’s suggestion. Most of the academic work in monetary finance is just plain wrong, or worse it’s the wrong answer to the wrong question being asked. And that’s what we have here. Anyone who thinks that Miran is an economic-denialist should read the speech. It is mostly a well-reasoned argument about all the reasons that the neutral rate may be lower now than it has been in the past. And I applaud him when he comments “I don’t want to imply more precision than I think it possible in economics.” Indeed, if we were to be honest about the degree of precision with which we measure the economy in real time and the precision of the models (even assuming they’re parameterized properly, which is questionable), the Fed would almost never be able to decisively reject the null hypothesis that nothing important has changed and therefore no rate change is required!
I can’t say that I agree with Miran’s argument though. Not because it’s wrong, but because it’s completely irrelevant.
Sometimes I think that geeks with their models is just another form of ‘boys with their toys.’ And that is what is happening here. The “neutral rate of interest” is a concept that is cousin to NAIRU, the non-accelerating-inflation rate of unemployment. The neutral rate, often called ‘r-star’ r* (which is your clue that we’re arguing about models), is the theoretical interest rate that represents perfect balance, where the economy will neither tend to generate inflation, nor tend to generate unemployment. Like I said, it’s just like NAIRU which is a level of unemployment below which inflation accelerates. And they have something else in common: they are totally unobservable.
Now, lots of things are unobservable. For example, gravity is unobservable. Yet we have a very precise estimate of the gravitational constant[1] because we can make lots of really precise measurements and work it out. Economists would love for you to think that what they’re doing with r* is similar to calibrating our estimate of the gravitational constant. It’s not remotely similar, for (at least) two enormous reasons:
- Measuring the gravitational constant is only possible because we know (as much as anything can be known) what the formula is that we are calibrating. Fg=Gm1m2/r2. So all we have to do is measure the masses, measure the distance between the centers of gravity, and infer the force from something else.[2] Then we can back into G, the gravitational constant. Here’s the thing. The theory of how interest rates affect inflation and growth, despite being ensconced in literally-weighty economics tomes, is just a theory. Actually, several different theories. And, by the way, a theory with a terrible record of actually working. To calibrate r*, the hand-waving that is being done is ‘assume that interest rates affect the economy through a James and Bartles equilibrium…’ or something like that. It is an assumption that we shouldn’t accept. And if we don’t accept it, calibrating r* is just masturbation via mathematics.[3]
- With the gravitational constant, every subsequent measurement and experiment confirms the original measurement. Every use of the model and the constant in real life, say by sending a spacecraft slingshotting around Jupiter to visit Pluto, works with ridiculous precision. On the other hand, r* has approximately a zero percent success rate in forecasting actual outcomes with anything like useful precision, and every person who measures r* gets something totally different. And r* – if it is even a real thing, which I don’t think it is – evidently moves all the time, and no one knows how. Which is Miran’s point, but the upshot is really that monetary economists should stop pretending that they know what they’re doing.
In short, we are arguing about an unmeasurable mental construct that has no useful track record of success, and we are using that mental construct to argue about whether policy rates should be at 2% or 4%. Actually, even worse, Miran says that the market rate he looks at is the 5y, 5y forward real interest rate extracted from TIPS. The Fed has nothing to do with that rate. But if that’s what he is looking at why are we arguing about overnight rates?
I should say that if there is such a thing as a ‘neutral rate’ that neither stimulates nor dampens output and inflation, I would prefer to get there by first principles. It makes sense to me that the neutral long-term real rate should be something like the long-run real growth rate of the economy. And if that’s true, then Miran is probably at least directionally accurate because as our working population levels off and shrinks, the economy’s natural growth rate declines (unless productivity conveniently surges) since output is just the product of the number of hours worked times the output per hour. But I can’t imagine that the economy ‘cares’ (if I may anthropomorphize the economy) about a 1% change in the long-run real or nominal interest rate, at least on any time scale that a monetary policymaker can operate at.
The best answer here is that whether Miran is right or not, the Fed should just pick a level of interest rates…I’m good with 3-4% at the short end…and then change its meeting schedule to once every other year.
[1] Which may in fact not be constant, but that’s a topic for someone else’s blog.
[2] In the first experiment to measure gravity, which yours truly replicated for a science fair project in high school, Henry Cavendish in 1797 figured the force in this equation by measuring the torsion force exerted by the string from which his two-mass barbell was suspended, with one of those masses attracted to another nearby mass.
[3] Yeah, I said it.
Inflation Guy’s CPI Summary (August 2025)
Before I begin talking about today’s CPI, a quick word about the 24th anniversary of the terrorist attacks of 9/11. As someone who worked 1 block from the Towers, I can tell you it’s a day I will never forget and filled with images I can never erase. But I also remember that in the weeks that followed, the country was unified in a way I’d never seen. Rudy Giuliani was “America’s Mayor” for his courage and steady hand during the disaster and in the period that followed. When I traveled to the Midwest, menus were filled with ‘Freedom Fries’ and strangers asked with concern about my family and friends when they heard I was from New York. It seems crazy to me that only 24 years removed from that, the country is divided in a way I’ve never seen. Everyone said “we will never forget.” And then they forgot.
But I do not forget. I give prayers and thanks for the brave first responders I saw that day and for the families of those who didn’t return. And you should too.
All of which makes the monthly CPI report seem very small. In truth, it is small all of a sudden. From being one of the most-important releases for a couple of years because of the Fed’s assumed reaction function, it has abruptly been pushed to the back. This is partly because of the weak Employment data and the massive downward revisions to the prior data but that point is reinforced by the Fed’s recent adjustment to the inflation targeting framework, in which they removed any imperative to make up for periods of high inflation by engineering lower inflation so that the reaction function is basically one way. (See my writeup on this at https://inflationguy.blog/2025/09/02/the-fate-of-fait-was-fated/.) I guess there’s an ironic parallelism here. After the inflationary 1970s and the pain of bringing inflation back down, the Fed said “we will never forget.” And then they forgot.
But I do not forget. And neither should you. An investor’s nominal returns are irrelevant (except to the IRS). What matters is real returns, and a period of higher and less-stable inflation has historically resulted in lower asset prices since the most important indicator of future returns over normal investing horizons is starting price. If markets need to adjust to higher inflation to give higher nominal returns, the easiest way to do that is to lower the starting price. So whether the Fed cares, we should.
And with that – we came into today with real yields having fallen some 20bps this month, but with inflation expectations having not declined much at all. Obviously, that’s the market’s reaction to the presumed tilt of the Fed.
The CPI report was slightly above expectations, which were already somewhat higher than in prior months. So when people tell you this was a ‘small miss higher,’ that’s mainly because economists adjusted their expectations, not because the number was similar to prior months. Month/month headline inflation (seasonally adjusted) was +0.382% (expectations were +0.33%), with core at +0.346% (expectations were +0.31%). Markets have not reacted poorly to this figure, but I wonder if core had been slightly higher and rounded to +0.4% if we’d have seen more introspection.
But as I said, this is a ‘small miss’ but that does not mean it was a small number. Indeed, with the exception of the jump in January associated with tariff noise, this is the highest core figure in 17 months.
There were a number of upside categories, but one of them was not Medical Care. Some people had been looking for a move higher here, and Doctor’s Services rose a bit, but Medicinal Drugs fell -0.372% m/m and is now down year/year. That surprises me, but there are a lot of pressures on the drug industry right now and it is going to take a while to see how it shakes out.
Core goods prices continued to accelerate. On a y/y basis, core goods are +1.54%. With the exception of the COVID spike, this is the highest level of core goods inflation since 2012. Some of that is definitely due to tariffs, and that will trickle in for a while. But the long-wave concern is that deglobalization/re-onshoring of production means that it will be very hard to get core goods inflation back to the persistent mild deflation we had enjoyed for a very long time. And without that, it is very hard to get core inflation to 2%, especially if core services (+3.59% y/y) stops improving as the chart sort of hints it might.
One surprise you will hear a lot about is Owners Equivalent Rent, which was +0.38% m/m. Primary Rents were +0.30% m/m. Both of those are higher than the recent figures, but this looks like some residual seasonal-adjustment issues to me. The y/y for both continues to decline, albeit at a slowing rate, which means that the number we dropped off from last year was higher than the upside surprise of today.
Rents are on schedule.
We also saw another jump from airfares, +5.87% m/m, and Lodging Away from Home (+2.92% m/m) finally rebounded after months of weakness. Used cars were +1.04% m/m, and new cars +0.28%. When you look at all of the pieces, it adds up to Median CPI being almost the same as last month: my early guess is +0.276% m/m.
Turn that picture any way you want to. I don’t see a downtrend.
When we break down inflation into the four main pieces, none of them is in deflation and none seems to be an overt drag or pulling everything else up. Food and Energy is +2.16% y/y. Core goods is +1.54% y/y. Core services less rents (aka Supercore, chart below) is +3.56% y/y. And Rent of Shelter is +3.61%. How do you want to get inflation to 2% from those pieces?
Long-time readers will know this does not surprise me. Median CPI will be around 3.6% y/y again. That’s where we are. We overshot my ‘high 3s, low 4s’ target to the downside a bit, but we’re back up in the mid-to-high 3s. I’ll take that as a win.
I want to share the money supply chart. On an annualized basis, we’re near 6% y/y over the last six months. That is back to pre-COVID levels, and is too fast in this environment. You can’t get 2% inflation with deglobalization and sour demographics if you’re running the monetary playbook from when you had globalization and positive or neutral demographics.
And finally, we now know USDi’s price through the end of October.
So what does all of this mean for policy? Well, see what I said above about inflation targeting and the change of the Fed’s operating framework. The most important things to the FOMC right now are, in order:
- Employment
- Politics, and jockeying for position to be named next Fed Chair
- Internal modeling about tariffs, inflation expectations, rents, etc.
- Actual inflation numbers, like CPI
35th or so in importance is “the quantity of money,” if it’s on the list at all. You can probably glean from my list that I think the Fed is likely to ease. Let me make clear that I do not think that a wise Fed chair would even consider easing with median inflation steadying around 3.6%, and a 50bps cut would be laughable. However, this is not a wise Fed chairman, and this one is going to ease. In my gut, I think the Fed will cut 25bps but with several dissents for 50bps. I would not be shocked with a 50bps ease even though it is completely boneheaded to do it with inflation still running hot with no clear path for it to decline to what used to be the target.
But that’s the point I suppose. Is there even a target, if the Fed doesn’t mind missing it?
One final announcement. If you’re an investor in cryptocurrencies (in particular, stable or flatcoins) and have a Telegram account, consider joining the read-only USDi_Coin room https://t.me/USDi_Coin where the USDi Coin price is updated every four hours or so…and where many of these charts are also posted shortly after CPI just as I used to do on Twitter.
The Fate of FAIT was Fated
Growth in the US is ebbing, and it is likely only the AI boom that is keeping us from recording a small recession. Unemployment is still rising, although slowly, and credit delinquencies are rising. Because the services sector and the goods sector are still asynchronous – a holdover from the COVID period – we haven’t seen an aggregate contraction, but it will happen eventually. That doesn’t concern me. Recessions happen. It is only worrisome because equity markets are so ‘fully valued’ that an adjustment to a recession could be rough. On the other hand, all signs point to the Federal Reserve starting to ease, and this may support stocks. I would go so far as to say that investors are counting on that.
That is a rather ordinary problem. The bigger problem has not yet been realized by equity markets, but as we look at long maturities on the yield curve we see that yields are near the highs of the year even with the Fed expected to ease. That is not normal. When the Fed eases the curve tends to steepen, because however long the period of lower short rates, it will be a larger proportion of a shorter-maturity instrument. But long rates still decline in that case, normally.
You can insert your favorite story here, about how foreign investors hate Trump, or people are worried about inflation, or the credit profile of the United States. My preferred explanation (see “The Twin Deficits – One Out of Two IS Bad”) is that if you reduce the trade deficit sharply but do not reduce the budget deficit equally sharply, then the balance must be made up by domestic savers and that implies a higher rate of interest.
There’s also some reason to be wary of the turn higher in inflation, even though that was entirely foreseen (see “Ep. 145: Beware the Coming Inflation Bounce”) and a good part due to base effects. There are, though, some signs of underlying secular rather than cyclical pressures on prices. For example thanks partly to AI electricity prices started accelerating higher in 2021 but unlike other parts of the CPI have continued to rise. The CPI for Electricity stands 35% above the level of year-end 2020, and well beyond the long-term trend. Beef prices are 41% higher and still rising.
Of course, there are always prices that are rising but there are two reasons I am more concerned about this now. The first is that the money supply has returned to a positive and rising growth rate and is at a level inconsistent with long-term price stability even before the Fed renews its easing campaign.
Five percent was once a nice level for M2 growth, when demographics and globalization were following winds. Now they are headwinds and we need to be lower. Still, I wouldn’t get panicky about 5%. Get to 8% and I’ll be more concerned. But the reason that might happen concerns changes happening at the central bank.
What gets the headlines is the continual pressure that the Trump Administration is putting on Fed Chairman Powell and others on the Federal Reserve Board, several of whom are jockeying to be dovish enough to be selected as the next Fed Chair. But the much more important development was the 5-year review of the Fed’s operating framework, which Powell discussed at his Jackson Hole speech. The significance of this was seeming lost on most investors, although 10-year breakevens have gradually risen and are up at 2.42%, and other than in the post-COVID surge they’ve not been much higher than that since 2012 or so.
These are 10-year breakevens, so this isn’t a tariff effect. What’s going on here? Not much, yet, but…there is the change in the Fed’s framework, which I think is important.
Five years ago, the Fed abandoned a specific inflation target in favor of “Flexible Average Inflation Targeting”, or FAIT, which basically said “we are targeting 2% inflation, but only over time. So when inflation is too low for a while, then it’s okay to let it run hot for a while later.” At the time, this was a clear sign that monetarists – who don’t necessarily believe there is a tradeoff between inflation and growth like the Keynesians do – were losing the battle. More flexibility to respond to inflation ‘tactically’ is not something that we needed, and it wasn’t clear how that would be a helpful change anyway.
But the current 5-year framework adjustment is worse. It basically abandoned the good part of FAIT, which was any kind of soft commitment to be hawkish in the future if necessary. In Powell’s words – and I’m not making this up – “…we returned to a framework of flexible inflation targeting and eliminated the ‘makeup’ strategy.”
Yep, that’s what he said.
There is a lot more in Powell’s explanation, but most of it all leans in the same direction. For all my historical criticism of former Chairman Greenspan, he deserves credit for this: he used to say that achieving low and stable inflation was key to achieving maximum stable employment over time. Thus, inflation was primary, not secondary, in achieving the dual mandate. Now, the Fed ostensibly wants to target a low level of inflation…because that’s what central banks are supposed to do…but recognizes that sometimes they’ll want to emphasize lower rates to help Employment – and the important part is that as I just noted, they won’t ‘make up’ for running too much liquidity now by running less liquidity later. Does anyone want to take the other side of the bet that the Fed will have an easier time lowering rates and keeping them low, than raising them and keeping them high? Accordingly, the long-term inflation outlook just got worse. I don’t think we are returning to the 1970s, but we aren’t returning to 2% any time soon – and the Fed is okay with that!
FAIT was never a very good idea, and I didn’t think it would survive the first time inflation ran too high and dictated an extended period of very tight money. It didn’t. I didn’t think they’d actively make it worse, and maybe the joke’s on me. They always make it worse.
