A conversation with Tyler Cowen

Conversation with Tyler podcast interview. Perhaps predictably, the most challenging interview / podcast I've ever done. Video here  and embed below 

Update:

My comments on efficient markets and active management provoked a lot of email. 

I mentioned Jonathan Berk, and should have mentioned his coauthors Rick Green and Jules Van Binsbergen, on how active management can persist even though investors don't make any money on it. The basic idea is really clever:  A manager has 5% alpha skill on $10 milllion, i.e. he can earn $500k, but the skill does not scale. So he earns 5%, charges 1% fee, investors get 4%.  Investors see his great performance and rush in.  Now he has $50 million assets under management. He still earns $500k. He charges 1% fee, and investors get zero alpha. It’s equilibrium – if investors leave,  alpha to investors goes up again, and they return. Investors are earning the same zero alpha they get on the index so why not. And that’s about what we see. Fees persist in equilibrium, fees are equal to alpha on average, alpha post fees are about zero, flows follow performance. The seminal paper is "Mutual Fund Flows and Performance in Rational Markets" Jonathan B. Berk, Richard C. Green  Journal of Political Economy 2004  112 1269-1295 and a series following, here . It's not a perfect theory, but the glass is nearer full than empty, and it's a lovely supply and demand starting place to understand an industry that persists for decades. 

More generally, the average fund earns no alpha, almost guaranteed by free entry. The trouble is distinguishing the good ones from the bad ones, on ex-ante characteristics. The filters used by academics are pretty weak -- past returns, ratings, education of principals etc. On the other hand, now we just move it all up to the meta-game. Picking managers is no different than picking stocks. Skill on skill, alpha on alpha, fees on fees...

Inflation outlook at NRO. 1970s all over again?

Essay on monetary policy in National Review Online. 

Short version: The Fed's monetary policy has returned to the intellectual framework of the late 1960s. At best "expectations" now float around as an independent force, manipulable by speeches, but not tied to patterns of action by the Fed as analysis since the 1980s would require. 

If you follow the conventional reading of how monetary policy works, that observation leads to a natural prediction:  we're on the verge of reliving 1970s inflation. (Fiscal policy, entitlements, regulation and cities seem to be headed also to 1970s policy on steroids.) 

True, the Fed says "we have the tools" to stop inflation should it break out. But that tool is to rerun 1980. Does the Fed have the will? Will the Fed really induce a 2 year agonizing recession to bring down inflation, followed by 15 years of historically unprecedented high interest rates? Or will the Fed do what it did three times before that -- half-hearted interest rate rises that brought milder recessions, and a quick backtrack? Having even a nuclear weapon is useless if people stop believing you will use it. 

I don't follow that conventional reading, so I'm not confidently predicting inflation. I worry more about fiscal affairs directly than about the Fed, which leads to a fear of a larger but less predictable inflation, that the Fed will have little power to stop. But mine is definitely a minority view.   

Does the Fed’s Monetary Policy Threaten Inflation? (Contains Spoilers)

The central bank is headed back to the Seventies — a rerun that no one should want.

Does the Fed’s monetary policy threaten inflation? By conventional measures, yes. But those conventional measures have failed in the past. I believe that the short-run danger is less than it appears, but the long-run danger is larger.

If one reads Fed statements through conventional glasses, monetary policy seems to have been reset to the 1960s, and we know how that worked out.

r < g

r<g is an essay on the question whether r<g means the government can borrow and not worry about repaying debts. No. 

Abstract:

A situation that the rate of return on government bonds r is less than the economy's growth rate g seems to promise that borrowing has no fiscal cost. r<g is irrelevant for the current US fiscal problems. r<g cannot begin to finance current and projected deficits. r<g does not resolve exponentially growing debt. r<g can finance small deficits, but large deficits still need to be repaid by subsequent surpluses. The appearance of explosive present values comes by using perfect-certainty discount formulas with returns drawn from an uncertain world. Present values can be well behaved despite r<g. The r<g opportunity is like the classic strategy of writing put options, which fails in the most painful state of the world.

The essay is based on comments I gave at the spring NBER EFG meeting on Ricardo Reis' "The constraint on public debt when r<g but g<m." My discussion starts here at 4:48,  Ricardo presents the paper (very good, worth listening to, many points I didn't get to) at 4:30 

pdf for now, as translating equations to blogger is taxing. 

Fiscal theory of the price level draft

The Fiscal Theory of the Price Level is a book I'm writing on that topic. It now has a full draft, here. 

Comments, typos, suggestions, complaints, parts you find too easy, part you find too hard, things you think are wrong, parts you find repetitive, parts you find need better connection, things I should add, things I should delete are all most welcome! 

I also did a 2 hour video mini-course on FTPL for the Becker-Friedman Institute last summer, with slides/notes here. 

Update: The video link is now fixed (2/1/2012)

Inflation issues

 

In analyzing whether inflation is coming, Mickey Levy at Berenberg Capital passes along the above graph. These are price indices, so the upward or downward slope measures inflation. Is there inflation? That depends on whether you ask durable goods or services. 

Why are we experiencing durable good deflation, and will it last? Part of the answer is quality adjustment: 

Bisin on MMT Rhetoric

Alberto Bisin has written an intriguing short review of Stephanie Kelton's The Deficit Myth. Alberto focuses on the rhetoric of MMT and the book. (My review here FYI.) 

MMT's rhetoric is surely its most salient feature. It has been phenomenally successful in terms of gaining attention, and it has eschewed all the traditional rhetoric of economics -- academic articles, conference presentations, monographs full of equations, econometric estimates and tests, or even mountains of charts and graphs, PhD students fanning out to develop it. 

[In response to JZ comment, that is not necessarily good or bad, it's just a fact. The conventional economic rhetoric produces a lot of garbage, too.  Bryan Caplan has a point. The major distinction may be engagement with critics, which happens in conventional discourse and so far has been largely absent with MMT.]  

Kelton's book is unusual in MMT rhetoric for appearing to be one definitive source that would lay it out, following standard rhetoric. The trouble with writing a book is that sometimes people read it carefully, and are emboldened that they aren't missing something in the usual flurry of blog posts tweets and videos. Then the world finds out the ideas in it are empty, the rhetoric artifice rather than explanatory. 

(NB, "rhetoric" has gained an unfortunate pejorative in common usage. I mean no such pejorative. How we structure economic discussion is hugely important. If you have not read Deirdre McCloskey's Rhetoric of Economics article or subsequent books, do so immediately.)    

Alberto: 

The book should be seen as a rhetorical exercise. Indeed, it is the core of MMT that appears as merely a rhetorical exercise. As such it is interesting, but not a theory in any meaningful sense I can make of the word. The T in MMT is more like a collection of interrelated statements floating in fluid arguments. Never is its logical structure expressed in a direct, clear way, from head to toe.

Target the spread?

The Fed wants to control inflation. Now, it targets the nominal interest rate. But to do that it has to guess what the right real interest rate is. Nominal interest rate = real interest rate plus expected inflation.

Guessing the right price is hard for any planner, and guessing the right asset price doubly hard. If the Fed wants to target inflation, why not target the spread between real and indexed bonds, and let the level of interest rates float to wherever they want to go by market forces?

Nominal interest rate - real interest rate = expected inflation. So, if the Fed wants to see 2% expected inflation, why not target the difference between one year TIPS (indexed treasurys) and one year treasurys at 2%? Then expected inflation has to settle down to 2%

Indeed, beyond a target, the Fed could really nail this down with a flat supply curve. The Fed could nail expected inflation at 2% by offering to exchange, say, any amount of one-year zero coupon treasury bonds for 0.98 one-year zero coupon indexed treasurys (TIPS). And leave \(r^\ast\) and a lot of real rate prognosticating in the dustbin.

Obviously, you worry. If the Fed nails the spread at 2%, will everything else really settle down so that expected inflation is 2%? Or is this like holding the tail and hoping the dog will wag? We need to write down a model.

I just wrote such a model. This is part of the long-running fiscal theory of the price level book project. But it is a short independent point which blog readers may enjoy. And, I'm always nervous that I missed something in wild ideas like this (see the whole Neo-Fisherian business) so I enjoy comments.

I start with a really simple version of the model, \begin{align} x_{t} & =-\sigma\left( i_{t}-E_{t}\pi_{t+1}\right) \label{ISspread}\\ \pi_{t} & =E_{t}\pi_{t+1}+\kappa x_{t}.\label{NKspread}% \end{align} Here I have deleted the \(E_{t}x_{t+1}\) term in the first equation, so it becomes a static IS curve, in which output is lower for a higher real interest rate. This simplification turns out not to matter for the main point, which I verify by going through the same exercise with the full model. But it shows the logic with much less algebra. Denote the real interest rate \begin{equation} r_{t}=i_{t}-E_{t}\pi_{t+1}.\label{rdef}% \end{equation} We can view the spread target as a nominal interest rate rule that reacts to the real interest rate, \begin{equation} i_{t}=\alpha r_{t}+\pi^{e\ast}.\label{iar}% \end{equation} The spread target happens at \(\alpha=1\), but the logic will be clearer and the connection of an interest rate peg and interest spread peg clearer if we allow \(\alpha\in [0,1]\) to connect the possibilities.

Eliminating all variables but inflation from \eqref{ISspread}-\eqref{iar}, we obtain \begin{equation} E_{t}\pi_{t+1}=\frac{1-\alpha}{1-\alpha+\sigma\kappa}\pi_{t}+\frac {\sigma\kappa}{1-\alpha+\sigma\kappa}\pi^{e\ast}.\label{pidynsimple}% \end{equation}

For an interest rate peg, \(\alpha=0\), \(i_{t}=\pi^{e\ast}\), inflation is stable -- the first coefficient is less than one -- but indeterminate.

We complete the model with the government debt valuation equation, in linearized form \begin{equation} \Delta E_{t+1}\pi_{t+1}=-\Delta E_{t+1}\sum_{j=0}^{\infty}\rho^{j}% s_{t+1+j}-\Delta E_{t+1}\sum_{j=0}^{\infty}\rho^{j}r_{t+1+j}% ,\label{fiscalclose}% \end{equation} which determines unexpected inflation. We have a simplified version of the standard new-Keynesian fiscal theory model.

(Targeting the spread rather than the level of interest rates does not hinge on active fiscal vs. active monetary policy. In place of \eqref{fiscalclose}, one could determine unexpected inflation from an active monetary policy rule instead. One writes a threat to let the spread diverge explosively for all but one value of unexpected inflation, in classic new-Keynesian style. In place of \(i_{t}=i_{t}^{\ast }+\phi(\pi_{t}-\pi_{t}^{\ast})\), write \(i_{t}-r_{t}=\pi_{t}^{\ast}+\phi (\pi_{t}-\pi_{t}^{\ast})\), where \(\pi_{t}^{\ast}\) is the full inflation target, i.e. obeying \(\pi_{t}^{e\ast}=E_{t}\pi_{t+1}^{\ast}\) and \(\Delta E_{t+1}\pi_{t+1}^{\ast}\) the desired unexpected inflation. )

If the interest rate target responds to the real rate \(\alpha\in(0,1)\), the model solution has the same character. As \(\alpha\) rises, the dynamics of \eqref{pidynsimple} happen faster, so inflation dynamics behave more and more like the frictionless model, \(\kappa\rightarrow\infty\).

At \(\alpha=1\), the spread target \(i-r=\pi^{\ast}\) nails down expected inflation, as we intuited above. Equation \eqref{pidynsimple} becomes \[ E_{t}\pi_{t+1}=\pi^{e\ast}. \] Equation \eqref{fiscalclose} is unchanged and determines unexpected inflation, though the character of discount rate variation changes.

Inflation is not zero, but it is an unpredictable process, which in some sense is as close as we can get with an expected inflation target. Output and real and nominal rates then follow \begin{align*} x_{t} & =\frac{1}{\kappa}\left( \pi_{t}-\pi^{e\ast}\right) \\ r_{t} & =-\frac{1}{\sigma\kappa}\left( \pi_{t}-\pi^{e\ast}\right) \\ i_{t} & =\pi^{e\ast}-\frac{1}{\sigma\kappa}\left( \pi_{t}-\pi^{e\ast}\right) \end{align*} A fiscal shock here leads to a one-period inflation, and thus a one-period output increase. Higher output means a lower interest rate in the IS curve, and thus a lower nominal interest rate. The real and nominal interest rate vary due to market forces, while the central bank does nothing more than target the spread.

Of course we may wish for a more variable expected inflation target -- many model suggested it is desirable to let a long smooth inflation accommodate a shock. It's easy enough, say, to follow \(\pi_{t}^{e\ast}% =E_{t}\pi_{t+1}=\pi_{t}\) and even have a random walk inflation. Or, \(\pi _{t}^{e\ast}=p^{\ast}-p_{t}\) to implement an expected price level target \(p^{\ast}\) with one-period reversion to that target. Or \(\pi_{t}^{e\ast }=\theta_{\pi}\pi_{t}+\theta_{x}x_{t}\) in Taylor rule tradition. The point is not to defend a constant peg, but that a spread target is possible and will not explode in some unexpected way.

The same behavior occurs in the full new-Keynesian model, which is also the sort of framework one would use to think about the desirability of a spread target. I simultaneously allow shocks to the equations and a time-varying spread target. The model is \begin{align} x_{t} & =E_{t}x_{t+1}-\sigma(i_{t}-E_{t}\pi_{t+1})+v_{xt}\label{xspread}\\ \pi_{t} & =\beta E_{t}\pi_{t+1}+\kappa x_{t}+v_{\pi t}\label{pispread} \end{align} Write the spread target as \[ i_{t}-r_{t}=\pi_{t}^{e\ast}. \] With the definition \[ r_{t}=i_{t}-E_{t}\pi_{t+1}, \] we simply have \[ E_{t}\pi_{t+1}=\pi_{t}^{e\ast}. \] As in the simple model, the spread target directly controls equilibrium expected inflation. Unexpected inflation is set by the same government debt valuation equation \eqref{fiscalclose}. The other variables given inflation and unexpected inflation follow \[ x_{t}=\frac{1}{\kappa}\left( \pi_{t}-\beta\pi_{t}^{e\ast}-v_{\pi t}\right) \] \begin{equation} r_{t}=i_{t}-\pi_{t}^{e\ast}=-\frac{1}{\sigma}\left( \pi_{t}-\pi_{t}^{e\ast }\right) +\frac{\beta}{\sigma}\left( \pi_{t}^{e\ast}-E_{t}\pi_{t+1}^{e\ast }\right) +\frac{1}{\sigma}\left( v_{xt}+v_{\pi t}-E_{t}v_{\pi t+1}\right) \label{rit} \end{equation}

Following inflation, output still has i.i.d. deviations from the spread target, plus Phillips curve shocks. The real rate and nominal interest rate also have only i.i.d. deviations from the spread target, plus both IS\ and Phillips curve shocks. Output is not affected by IS shocks. The endogenous real rate variation \(\sigma r_{t}=v_{xt}\) offsets the IS shock's effect on output in the IS equation \(x_{t}=E_{t}x_{t+1}-\sigma r_{t}+v_{xt}\). This is an instance of desirable real rate variation that the spread target accomplishes automatically. (To obtain \eqref{rit} first-difference \eqref{pispread} and then substitute \(x_{t}-E_{t}x_{t+1}\) from \eqref{xspread}.)

I conclude, it could work. The Fed could target the spread between indexed and non-indexed debt. Doing so would nail down expected inflation. The Fed could then let the level of real and nominal rates float according to market forces. If every other price that has ever been set free is any guide, real and nominal interest rates would float around a lot more than anyone expects.

The result is almost, but not quite, a holy grail of monetary economics. The gold standard has a lot of appeal, as the Fed needs only exchange dollars for gold at a set rate and do no other grand financial central planning. Alas, the value of gold relative to everything else varies too much. We would like something like a CPI standard, which automatically stabilizes the price of everything else in terms of dollars. But the Fed can't buy and sell a basket of the CPI. Indexed bonds (or CPI futures) are nearly the same thing. And here the Fed just trades one year nominal debt for one year real debt. But it's not quite a CPI standard since it only sets expected inflation, not actual inflation. We still need fiscal policy, or new-Keynesian off equilibrium threats, to pick unexpected inflation. Still, guaranteeing that long-sought "anchoring" of expectations seems like a first step.

What else could go wrong? Well, this is just the first simple model, but it's a step. Obviously it depends on the forward looking Phillips curve. So in that sense it may be best as a longer run target and a regime, in which rational expectations and forward looking behavior are good assusmptions, rather than trying to set expected inflation at a daily horizon or try to do something one time that surprises markets.

I would advise the Fed to start paying a lot more attention to the spread. Next, work on increasing the liquidity of indexed debt. Ideally the Treasury should fix debt markets, vastly simplifying TIPS. I've argued for tax free indexed and non-indexed perpetuities, which would be ideal. But the Fed could and should start offering indexed and nominal term financing, for many reasons. If the Fed is going to buy a lot of long-dated Treasurys, it shold issue term liabilities not just floating-rate overnight reserves. Issing term indexed liabilites is a good next step, and there's nothing more liquid than Fed liabilities! Then start gently pushing the spread to where the Fed wants the spread to go. Start buying and selling bonds to push the spread around. Get to the point of a flat supply curve slowly. Heavens, the Fed doesn't trust interest rate targets and QE enough yet to offer a flat supply curve!

A Neo-Fisherian Challenge and Reconciliation

 Lars Svensson has a very interesting challenge to the Neo-Fisherian view. (See link for slides.) 

What happens to inflation and unemployment when the central bank (for no good reason) raises the policy rate by 175 bp?...

Sweden did, which provides  

..a natural experiment of the neo-Fisherian view: Does inflation really increase after a policy-rate increase? 

Despite roughly the same circumstances as many other countries, including the US, Sweden in 2010 raised rates 175 bp. (Top left graph). The result: Inflation fell, the exchange rate appreciated. Unemployment also rose (not shown).  

Debt still matters

Debt still matters  is an essay on debt at the Chicago Booth Review. It is a cleaned up and edited version of previous blog posts here and here, but a better essay.  

1933 lessons for today

Nov 11, Eric Leeper presented "Recovery of 1933" with Margaret  Jacobson and  Bruce Preston, at the Hoover "Road Ahead for Central Banks" series, and it was my pleasure to discuss it. This is a really important and insightful paper.  

Since Japan hit the zero bound more than 25 years ago, economists have been thinking about how to avoid deflation. The answer seems obvious -- "helicopter money," or "unbacked fiscal expansion." But this has proved remarkably hard to do. Jacobson, Leeper and Preston show us how the Roosevelt Administration managed a credible unbacked fiscal expansion, and it bears important lessons today. 

Sumner review of Strategies for Monetary Policy

Scott Sumner posted an excellent  Review of Strategies for Monetary Policy (Book information and, yes free pdfs here). By "excellent," I don't mean he agrees with everything, especially that I wrote! He read the whole thing, including comments, and provides a concise summary along with insightful critique. I won't try to summarize his summary -- it's all good. 

The book summarizes last year's conference on monetary policy at Hoover, which focused on the Fed and ECB policy reviews. This year's analogue is unfolding via zoom,  and has had a really interesting set of papers and discussions. More coverage will follow.  

Virtual finance theory seminar

I'm giving "A fiscal theory of monetary policy with partially-repaid long-term debt" at the virtual finance theory seminar, Wed Oct 28 at 1 PM EDT. Brett Green leads off with "Due Diligence" at 12 PM EDT. If interested, come join. Warning: this is an academic theory paper whose whole point is to look at equations. 

The link has an email address which I don't want to post here, email for a zoom invitation. 

This is an excellent seminar series and one of the first of the new international zooms, which are an exciting development. Thanks to Linda Schilling for organizing.

Challenges for central banks.

On October 20, I was graciously invited to give a talk at the  ECB Conference on Monetary Policy: bridging science and practice. 

I survey six challenges facing central banks: 1. Interest rates and inflation; 2. Policy reviews; 3. Financial reform post 2008 4. New challenges to finance post covid; 5. The many risks ahead; 6. Central banks and climate.  

For the whole thing, go here for a pdf. A video of my presentation is here. (The conference website will have all videso soon.) Items 1-5 are mostly interesting for monetary economists, though general readers might find my summary and distillation of the Fed policy review of some interest. 

Here, I post the section on climate change and conclusion, which are the most novel. And if you like the general approach and want to see it applied to the rest of what central banks are up to, that's another advertisement to read the whole talk pdf. 

In the section leading up to this, I describe risks to the financial system from widespread defaults, sovereign defaults, a US debt and currency crisis, another bigger pandemic, war, political chaos, cyber disaster and a few other unpleasant possibilities. But covid has taught us to prepare for the unexpected.  

....Which brings me to a great puzzle. In this context why are the ECB, BoE, BIS, IMF consumed with one and only one “risk”… climate? 

Challenge 6. Climate, Mission creep, and Politicization risk. 

I think this adventure is a dangerous mistake. 

Disclaimer: I do not argue that climate change is fake or unimportant. None of my comments reflect any argument with scientific fact. (I favor a uniform carbon tax in return for essentially no regulation.) 

The question is whether the ECB, other central banks, and international institutions such as the IMF, BIS, and OECD should appoint themselves to take on climate policy, or other important social, environmental or political causes, without a clear mandate to do so from politically accountable leaders. 

Moreover, the ECB and others are not just embarking on climate policy in general. They are embarking on the enforcement of one particular set of climate policies — policies to force banks and private companies to de-fund fossil fuel industries, even while alternatives are not available at scale, and to provide subsidized funding to an ill-defined set of “green” projects. 

To be concrete, I quote from Executive Board Member Isabel Schnabel’s recent speech. I don’t mean to pick on her, but she expresses the climate agenda very well, and her speech bears the ECB imprimatur. She recommends

"First, as prudential supervisor, we have an obligation to protect the safety and soundness of the banking sector. This includes making sure that banks properly assess the risks from carbon-intensive exposures…"

Let me speak out loud the unclothed emperor fact: Climate change does not pose any financial risk, at the 1, 5 or even 10 year horizon at which one can conceivably assess the risk to bank assets.

“Risk” means variance, unforeseen events. We know exactly where the climate is going in the next 5 to 10 years. Hurricanes and floods, though influenced by climate change, are well modeled for the next 5 to 10 years. Advanced economies and financial systems are remarkably impervious to weather. Relative market demand for fossil vs. alternative energy is as easy or hard to forecast as anything else in the economy. Exxon bonds are factually safer, financially, than Tesla bonds, and easier to value. The main risk to fossil fuel companies is that regulators will destroy them, as the ECB proposes to do, a risk regulators themselves control. And political risk is a standard part of bond valuation. 

That banks are risky because of exposure to carbon-emitting companies, that carbon-emitting company debt is financially risky because of unexpected changes in climate, in ways that conventional risk measures do not capture, that banks need to be regulated away from that exposure because of risk to the financial system is nonsense. (And if it were not nonsense, regulating bank liabilities away from short term debt and towards more equity would be a more effective solution to the financial problem.) 

Debt podcast and reconciliation

 

The Grumpy Economist podcast is back, with some thought on the debt issues from my last posts here and here.

David Andofatto had some final thoughts at macro mania, with which I mostly agree. Yes a twitter/blog debate in macroeconomics produces agreement! Central points: 

1) For these purposes a large sharp inflation and a default are not much different. In fact, the event I have in mind is most likely an inflation, as the US is likely to choose inflation over default. I don't think I made this equivalence clear in the debt posts. Also, the Fed is just another issuer of interest-paying debt. 

However, I don't think the chance of default or haircut is as remote as everyone else seems to think. They are also related events. Remember, my scenario for a debt crisis posits an economic and political crisis at the same time -- pandemic, recession, war, huge demands on the US treasury. Just how sacrosanct will full repayment of debt be to the US political system? When Chinese central bankers and Wall Street fat-cats are pressing for debt repayment but ordinary Americans are hurting, will our political system really take hard measures to repay the former in full, while throwing everyone's lives into misery via inflation? Maybe, and maybe inflation can still be blamed on speculators and middle-people and the usual bogey-people but maybe not. A haircut on Treasurys is not inconceivable. It could also come via refusal to raise the debt limit, or via a sharp wealth tax. And if people start to fear a haircut coming, they will certainly dump debt immediately, so fear of even technical defaults can spark the inflation.  

2) Yes, a good part of current r<g may well be a liquidity premium for US government debt due to its usefulness in transactions. But the big questions for r<g remain how reliable and how scaleable. Liquidity demand is not very scaleable. For example, if a government is financed only by money and no debt, and money demand MV=PY, then the government can run perpetual small deficits as the real economy Y and hence money demand grow. But if the government sees this situation, says "great, r<g, let's blow $10 trillion bucks," it will soon discover this opportunity does not scale at all. 

In the more reasonable MV(i)=PY that money demand is interest elastic, as the government exploits the opportunity and supplies more M it must pay greater interest on money (interest on reserves, interest on money-like treasurys), eating away quickly at r<g. 

The sensible r<g advocates like Blanchard recognize that r<g does not scale infinitely, and that a rise in r captures its limit. However, the discussion usually goes quickly to crowding out and the marginal product of capital rising. The liquidity effect that depresses US government bond yields is likely much less scaleable than crowding out of the whole US capital stock. 

When you read estimates of how much r rises as debt/GDP rises, pay attention to which mechanism they have in mind. 

Liquidity demand is also more fickle. Money demand can rise and fall quickly. The portion of treasury demand that comes from its use in financial transactions can be undone by different payment and clearing technology. Relying on this poorly understood mechanism for 30 years of r<g to pay off our debt seems a bit risky. US sanctions and regulations are creating a big incentive for others to create such alternative mechanisms. 

3) The government should borrow longer. The Fed can help.  

One of my policy conclusions is that the US government should borrow long-term as households who fear a big rise in interest rates should get 30 year mortgages not adjustable rate mortgages. Currently the Fed is actively undoing the Treasury's meager efforts to borrow long term, by buying up long-term treasury and guaranteed agency debt and issuing overnight reserves in return, and by issuing new debt in the form of overnight debt. 

The Fed could easily introduce term deposits -- reserves that carry a fixed interest rate, rather than a floating rate, and whose principal value varies. The Fed could also engage in fixed-for-floating swap contracts to eliminate the government's exposure to interest rate risk. (Such swap contracts should be collateralized of course, since you don't buy insurance from someone you will bail out if they lose money!) If interest rates rise the Fed will not just rescue the US government from a crisis, but will look like bloody geniuses. Which would you rather as a central banker in a crisis: a huge rise in net worth with which you can bail out the Treasury, or to fight an immense mark-to-market loss? 

More on debt

Following my last post on debt I've thought a bit more, and received some very useful emails from colleagues. 

A central clarifying thought emerges. 

The main worry I have about US debt is the possibility of a debt crisis. I outlined that in my last post, and (thanks again to correspondents) I'll try to draw out the scenario later. The event combines difficulty in rolling over debt, the lack of fiscal space to borrow massively in the next crisis. The bedrock and firehouse of the financial system evaporates when it's needed most. 

To the issue of a debt crisis, the whole debate about r<g, dynamic inefficiency, sustainability, transversality conditions and so forth is largely irrelevant. 

We agree that there is some upper limit on the debt to GDP ratio, and that a rollover crisis becomes more likely the larger the debt to GDP ratio.  Given that fact, over the next 20-30 years and more, the size of debt to GDP and the likelihood of a debt crisis is going to be far more influenced by fiscal policy than by r-g dynamics. 

In equations with D = debt, Y = GDP, r = rate of return on government debt, s = primary surplus, we have* \[\frac{d}{dt}\frac{D}{Y} = (r-g)\frac{D}{Y} - \frac{s}{Y}.\] In words, growth in the debt to GDP ratio equals the difference between rate of return and GDP growth rate, less the ratio of primary surplus (or deficit) to GDP. 

Now suppose, the standard number, r>g, say r-g = 1% or so. That means to keep long run average 100% debt/GDP ratio, the government must run a long run average primary surplus of 1% of GDP, or $200 billion dollars. The controversial promise r<g, say r-g = -1%, offers a delicious possibility: the government can keep the debt/GPD ratio at 100% forever, while still running a $200 billion a year primary deficit! 

But this is couch change! Here are current deficits from the CBO September 2 budget update

We were running $1 trillion deficits before the pandemic. Each crisis seems to bring greater stimulus.  

I especially like this view because it doesn't make sense that an interest rate 0.1% above the growth rate vs. an interest rate 0.1% below the growth rate should make a dramatic difference to the economy. Once you recognize some limit on the debt/GDP ratio, and desirability of some long-run stable debt/GDP, there is no big difference between these two values. The surplus required to stabilize debt to GDP smoothly runs from negative couch change to positive couch change. 

I find this a liberating proposition. I find the whole sustainability, long run limits, dynamic inefficiency, transversality condition and so forth a big headache. For the question at hand it doesn't matter! (There are other questions for which it does matter, of course.) 

As we look forward,  debt/GDP dynamics for the next 20 years are going to be dominated by the primary surplus/deficit, not plausible variation in r-g. The CBO's 10 years of 6-8% of GDP overwhelm 1-2% of r-g. If each crisis continues to ratchet up 10% of GDP deficits per year, more so. The Green New Deal, and large federal assumption of student debts, state and local debts, pension obligations, and so forth would add far more to debt/GDP than decades of r vs. g.  

**********

Now that this is clear, I realize I did not emphasize enough that Olivier Blanchard's AEA Presidential Address  acknowledges well the possibility of a debt crisis: 

Fourth, I discuss a number of arguments against high public debt, and in particular the existence of multiple equilibria where investors believe debt to be risky and, by requiring a risk premium, increase the fiscal burden and make debt effectively more risky. This is a very relevant argument, but it does not have straightforward implications for the appropriate level of debt.

See more on p. 1226. Blanchard's concise summary

there can be multiple equilibria: a good equilibrium where investors believe that debt is safe and the interest rate is low and a bad equilibrium where investors believe that debt is risky and the spread they require on debt increases interest payments to the point that debt becomes effectively risky, leading the worries of investors to become self-fulfilling.

Let me put this observation in simpler terms. Let's grow the debt / GDP ratio to 200%, $40 trillion relative to today's GDP. If interest rates are 1%, then debt service is $400 billion. But if investors get worried about the US commitment to repaying its debt without inflation, they might charge 5% interest as a risk premium. That's $2 trillion in debt service, 2/3 of all federal revenue. Borrowing even more to pay the interest on the outstanding debt may not work. So, 1% interest is sustainable, but fear of a crisis produces 5% interest that produces the crisis. 

Brian Riedi at the Manhattan Institute has an excellent exposition of debt fears. On this point, 

... there are reasons rates could rise. ...

market psychology is always a factor. A sudden, Greece-like debt spike—resulting from the normal budget baseline growth combined with a deep recession—could cause investors to see U.S. debt as a less stable asset, leading to a sell-off and an interest-rate spike. Additionally, rising interest rates would cause the national debt to further increase (due to higher interest costs), which could, in turn, push rates even higher.

***********

So how far can we go? When does the crisis come?  There is no firm debt/GDP limit. 

Countries can borrow a huge amount when they have a decent plan for paying it back. Countries have had debt crises at quite low debt/GDP ratios when they did not have a decent plan for paying it back. Debt crises come when bond holders want to get out before the other bond holders get out. If they see default, haircuts, default via taxation, or inflation on the horizon, they get out. r<g contributes a bit, but the size of perpetual surplus/deficit is, for the US, the larger issue. Again, r<g of 1% will not help if s/Y is 6%. Sound long-term financial strategy matters. 

From the CBO's 2019 long term budget outlook (latest available) the outlook is not good. And that's before we add the new habit of massive spending. 

Here though, I admit to a big hole in my understanding, echoed in Blanchard and other's writing on the issue. Just how does a crisis happen? "Multiple equilibria" is not very encouraging. Historical analysis suggests that debt crises are sparked by economic and political crises in the shadow of large debts, not just sunspots.  We all need to understand this better.  

******

Policy. 

As Blanchard points out, small changes do not make much of a difference.  

 a limited decrease in debt—say, from 100 to 90 percent of GDP, a decrease that requires a strong and sustained fiscal consolidation—does not eliminate the bad equilibrium. ...

Now I disagree a bit. Borrowing 10% of GDP wasn't that hard! And the key to this comment is that a temporary consolidation does not help much. Lowering the permanent structural deficit 2% of GDP would make a big difference! But the general point is right. The debt/GDP ratio is only a poor indicator of the fiscal danger. 5% interest rate times 90% debt/GDP ratio is not much less debt service than 5% interest rate times 100% debt/GDP ratio. Confidence in the country's fiscal institutions going forward much more important. 

At this point the discussion usually devolves to "Reform entitlements" "No, you heartless stooge, raise taxes on the rich." I emphasize tax reform, more revenue at lower marginal rates. But let's move on to unusual policy answers. 

Borrow long. Debt crises typically involve trouble rolling over short-term debt. When, in addition to crisis borrowing, the government has to find $10 trillion new dollars just to pay off $10 trillion of maturing debt, the crisis comes to its head faster. 

As blog readers know, I've been pushing the idea for a long time that especially at today's absurdly low rates, the US government should lock in long-term financing. Then if rates go up either for economic reasons or a "risk premium" in a crisis, government finances are much less affected. I'm delighted to see that Blanchard agrees: 

to the extent that the US government can finance itself through inflation-indexed bonds, it can actually lock in a real rate of 1.1 percent over the next 30 years, a rate below even pessimistic forecasts of growth over the same period

It's not a total guarantee. A debt crisis can break out when the country needs to borrow new money, even absent a roll over problem. But avoiding the roll-over aspect would help a lot! Greece got in trouble because it could not roll over debts, not because it could not borrow for one year's spending. 

Contingent plans? Blanchard's concise summary adds another interesting option 

 contingent increases in primary surpluses when interest rates increase. 

I'm not quite sure how that works. Interest rates would increase in a crisis precisely because the government is out of its ability or willingness to tax people to pay off bondholders. Does this mean an explicit contingent spending rule? Social security benefits are cut if interest rates exceed 5%? That's an interesting concept. 

Or it could mean interest rate derivatives. The government can say to Wall Street (and via Wall Street to wealthy investors) "if interest rates exceed 5%, you send us a trillion dollars." That's a whole lot more pleasant than an ex-post wealth tax or default, though it accomplishes the same thing. Alas, Wall Street and wealthy bondholders have lately been bailed out by the Fed at the slightest sign of trouble so it's hard to say if such options would be paid. 

Growth. Really, the best option in my view is to work on the g part of r-g. Policies that raise economic growth over the next decades raise the Y in D/Y, lowering the debt to GDP ratio; they raise tax revenue at the same tax rates; and they lower expenditures. It's a trifecta. In my view, long-term growth comes from the supply side, deregulation, tax reform, etc. Why don't we do it? Because it's painful and upsets entrenched interests. For today's tour of logical possibilities if you think demand side stimulus raises long term growth, or if you think that infrastructure can be constructed without wasting it all on boondoggles, logically, those help to raise g as well. 

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*Start with \(\frac{dD}{dt} = rD - s.\) Then \( \frac{d}{dt}\frac{D}{Y} =  \frac{1}{Y}\frac{dD}{dt}-\frac{D}{Y^2}\frac{dY}{dt}.\)

*** 

Update: David Andolfatto writes, among other things, 

"Should we be worried about hyperinflation? Evidently not, as John does not mention it"

For these purposes, hyperinflation is equivalent to default. In fact, a large inflation is my main worry, as I think the US will likely choose default via inflation to explicit default. This series of posts is all about inflation. Sorry if that was not clear. 

also 

Is there a danger of "bond vigilantes" sending the yields on USTs skyward? Not if the Fed stands ready to keep yields low.

All the Fed can do is offer overnight interest-paying government debt in exchange for longer-term government debt. If treasury markets don't want to roll over 1 year bonds at less, than, say, 10%, why would they want to hold Fed reserves at less than 10%? If the Fed buys all the treasurys in exchange for reserves that do not pay interest, that is exactly how we get inflation. And mind the size. The US rolls over close to $10 trillion of debt a year. Is the Fed going to buy $10 trillion of debt? Who is going to hold $10 trillion of reserves, who did not want to hold $10 trillion of debt. 

In a crisis, even the Fed loses control of interest rates. 

 

Magical monetary theory full review

I read Stephanie Kelton's book, The Deficit Myth: Modern Monetary Theory and the Birth of the People’s Economy,” and wrote this review for the Wall Street Journal. Now that 30 days have passed I can post the whole thing. 

I approached this task with an open mind. What I had heard of MMT has some overlap with fiscal theory of the price level, on which I work, and I hoped to see some commonality.

I was disappointed.

The review:

Modern monetary theory, known as MMT, erupted suddenly into the public consciousness when it won the attention of high-profile politicians including Bernie Sanders and Alexandria Ocasio-Cortez and their media admirers. Its central proposition states that the U.S. federal government can and should freely print money to finance a massive spending agenda, with no concern about debt and deficits.

What is MMT? Its advocates have told us in essays, blog posts, videos and tweets what MMT says about this and that, but what is its logic and evidence? As a monetary theorist who is also skeptical of conventional wisdom, I looked forward to a definitive exposition from Stephanie Kelton’s “The Deficit Myth: Modern Monetary Theory and the Birth of the People’s Economy.”

Ms. Kelton, a professor of economics at Stony Brook University and senior economic adviser to Bernie Sanders’s presidential campaign, starts with a few correct observations. But when the implications don’t lead to her desired conclusions, her logic, facts and language turn into pretzels.

True, the federal government can spend any amount by simply printing up the needed money (in reality, creating bank reserves). True, our government need never default since it can always print dollars to repay Treasury bonds. But if the government prints up and spends, say, $10 trillion, will that not lead to inflation? Ms. Kelton acknowledges the possibility: “If the government tries to spend too much in an economy that’s already running at full speed, inflation will accelerate.”

So how do we determine if the economy is running at full speed, or full of “slack,” with unemployed people and idle businesses that extra money might put to work without inflation? Ms. Kelton disdains the Federal Reserve’s noninflationary or “natural” unemployment rate measure of slack as a “doctrine that relies on human suffering to fight inflation.” Even the recent 3.5% unemployment is heartlessly too high for her.

“MMT urges us to think of slack more broadly.” OK, but how? She offers only one vaguely concrete suggestion: When evaluating spending bills, “careful analysis of the economy’s . . . slack would guide lawmakers. . . . If the CBO [Congressional Budget Office] and other independent analysts concluded it would risk pushing inflation above some desired inflation rate, then lawmakers could begin to assemble a venue of options to identify the most effective ways to mitigate that risk.” She doesn’t otherwise define slack or even offer a conceptual basis for its measurement. She just supposes that the CBO will somehow figure it out. She doesn't mention that the CBO now calculates a measure, potential GDP, which does not reveal perpetual slack. And she later excoriates the CBO for its deficit hawkishness.

Really her answer is: Don’t worry about it. She simply asserts that “there is always slack in the form of unemployed resources, including labor.”

We’re not talking about a little slack either. Ms. Kelton’s “people’s economy” starts with the full Green New Deal and moves on to a federal job for anyone, free health care, free child care, the immediate cancelation of student debt, free college, “affordable housing for all our people,” national high-speed rail, “expanded Social Security,” “a more robust public retirement system,” “middle-class tax cuts,” and more. How much does this add up to? $20 trillion? $50 trillion? She offers no numbers. How is it vaguely plausible that the U.S. has this much productive capacity lying around going to waste?

In a book about money, the inflation of the 1970s and its defeat are astonishingly absent. History starts with Franklin Roosevelt—a hero for enacting the New Deal but a villain for paying for it with payroll taxes rather than fresh dollars. Ms. Kelton praises John F. Kennedy, too. He “pressured unions and private industry, urging them to keep wage and price increases to a minimum to avoid driving inflation higher. It worked. The economy grew, unemployment fell sharply and inflation remained below 1.5 percent for the first half of the decade.”

The second half of that decade—Lyndon Johnson’s Great Society and Vietnam War spending, inflation’s breakout, Richard Nixon’s [1971] disastrous price controls—is AWOL. Did we not try MMT once and see the inflation? Did not every committee of worthies always see slack in the economy? Did not the 1970s see stagflation, refuting Ms. Kelton’s assertion that inflation comes only when there is no “slack”? Don’t look for answers in “The Deficit Myth.”

Victory over inflation under Ronald Reagan and Margaret Thatcher goes likewise unmentioned. History starts up again when Ms. Kelton excoriates Thatcher for saying that government spending has to be paid for with taxes. She insinuates, outrageously, that Thatcher deliberately lied on this point in order to “discourage the British people from demanding more from their government.”

If spending can be financed by printing money, “why not eliminate taxes altogether?” Ms. Kelton begins consistently. She criticizes Sens. Bernie Sanders and Elizabeth Warren for claiming that they need to raise taxes to pay for spending programs. But then why raise taxes? Taxes exist to decapitate the wealthy, not to fund spending or transfers: “We should tax billionaires to rebalance the distribution of wealth and income and to protect the health of our democracy.”

She offers a second answer, more subtle, and revealingly wrong. She starts well: “Taxes are there to create a demand for government currency.” This is a deep truth, which goes back to Adam Smith. Soaking up extra money with fiscal surpluses [higher taxes or less spending] is, in fact, the ultimate control over inflation. But then arithmetic fails her. To avoid inflation, all the new money must eventually be soaked up in taxes. The new spending, then, is ultimately paid for with those taxes.

What about the debt? Ms. Kelton asserts the government can wipe it out. Again, she starts correctly: The Fed could purchase all of the debt in return for newly created reserves. She continues correctly: The Fed could stop paying interest on reserves. But in conventional thinking, these steps would result in a swift inflation that is equivalent to default. Ms. Kelton asserts instead that these steps “would tend to push prices lower, not higher.” She reasons that not paying interest would reduce bondholders’ income and hence their spending.

 The mistake is easy to spot: People value government debt and reserves as an asset, in a portfolio. If the government stops paying interest, people try to dump the debt in favor of assets that pay a return and to buy goods and services, driving up prices.

What about all the countries that have suffered inflation, devaluation and debt crises even though they print their own currencies? To Ms. Kelton, developing nations suffer a “deficit” of “monetary sovereignty” because they “rely on imports to meet vital social needs,” which requires foreign currency. Why not earn that currency by exporting other goods and services? “Export-led growth . . . rarely succeeds.” China? Japan? Taiwan? South Korea? Her goal posts for “success” must lie far down field.

The problem is that “the rest of the world refuses to accept the currencies of developing countries in payment for crucial imports.” Darn right we do. Her solution: more printed money from Uncle Sam—a “global job guarantee.”

She also advises small and poor countries to cut themselves off from international commerce. They should develop “efficient hydroponic and aquaponics food production” and install “solar and wind farms” rather than import cheap food and oil. They should refuse international investment, with the “classical form of capital controls” under Bretton Woods as an ideal. “We share only one planet,” she writes, yet apparently that planet must have hard national borders.

By weight, however, most of the book is not about monetary theory. It’s rather a recitation of every perceived problem in America: the “good jobs deficit,” the “savings deficit,” the “health-care deficit,” the “infrastructure deficit,” the “democracy deficit” and—of course —the “climate deficit.” None of this is original or relevant. The desire to spend is not evidence of its feasibility.

Much of “The Deficit Myth” is a memoir of Ms. Kelton’s conversion to MMT beliefs and of her time in the hallways of power. She criticizes Democrats, including President Obama and his all-star economic team, for their thick skulls or their timidity to state her truth in public. Republicans, such as former House Speaker Paul Ryan, are just motivated by dark desires to keep the people down and enrich big corporations and wealthy fat cats. President Trump’s tax cuts are a “crime.” How insightful.

In a revealing moment, Ms. Kelton admits that “MMT can be used to defend policies that are traditionally more liberal . . . or more conservative (e.g., military spending or corporate tax cuts).” Well, if so, why fill a book on monetary theory with far-left wish lists? Why insult and annoy any reader to the right of Bernie Sanders’s left pinkie?

Writing the book to “defend” an immense left-wing spending agenda destroys her argument. If you could only feel her singular empathy for the downtrodden, if you could, as she does, view the federal budget as a “moral document,” if you could just close your eyes and need it to be true as much as she does, your “Copernican moment” will arrive, and logic and evidence will no longer trouble you.

That effect is compounded by her refusal to abide by the conventional norms of economic and public-policy discourse. She cites no articles in major peer-reviewed journals, monographs with explicit models and evidence, or any of the other trappings of economic discourse. The rest of us read and compare ideas. Ms. Kelton does not grapple with the vast and deep economic thinking since the 1940s on money, inflation, debts, stimulus and slack measurement. Each item on Ms. Kelton’s well-worn spending wish list has raised many obvious objections. She mentions none.

Skeptics have called it “magical monetary theory.” They’re right.

****

Update. To "jabmorris" and "rob." How could you possibly know if I have or have not read the book? As a matter of fact, I read every word of it. You offer a false accusation of impropriety, that you could not possibly know anything about, instead of a shred of fact or logic. This seems about par for the course in MMT land.

New "Fiscal theory of the price level" draft.

I posted a new draft of The fiscal theory of the price level, a slowly emerging book manuscript. It's heavily revised through Chapter 6.

Chapter 5 has a much better treatment of sticky price models. The mechanics of writing new-Keynesian + fiscal theory models are really easy. Invitation: there is a great paper-writing recipe in here! Chapter 6 includes empirical work, also ripe for extension. Both chapters summarize recent papers  A fiscal theory of monetary policy with partially repaid long term debt and The fiscal roots of inflation.

I've clarified and emphasized a point that's been floating around but not clearly enough: governments who borrow (deficits) do convince markets that they will subsequently repay debts (surpluses) at least in part. The surplus process has an s-shape, not an AR(1) shape. If governments do not do so, then they cannot raise revenue from bond sales, and they cannot finance deficits by selling debt.  The evident fact that they do both is some of the strongest evidence for an s-shaped surplus process. Much fiscal theory analysis, apparent rejections, and puzzles come down to ruling out this (with hindsight) simple fact, and also forgetting some lessons of 1980s time-series econometrics.

The book draft is up to solicit comments, which I welcome, best by private email. The links take you to a new website. I discourage browsing around for the moment as it is heavily under construction. I can't access my Booth website anymore, so a new one is coming but slowly.

Update: LAL, yes, thanks. (I can't seem to post comments on my own blog, so I have to answer here.)

Perpetuities, debt crises, and inflation

My brief exchange with Markus Brunnermeier at the end of a Covid-19 talk  attracted some attention, and merits a more detailed intervention. Gavin Davies at FT made some comments (more later) as did the Economist.

My proposal to fund the US with perpetuities comes from a paper, here. (Sorry regular readers for the repeated plug.)  The rest is standard fiscal theory of the price level, spread over too many papers to give one more plug.

There are three main points.  First, inflation is not about money anymore -- the choice of money vs. bonds. Money -- reserves -- pay interest, so reserves are just very short-term government bonds. Inflation is about the the overall demand for government debt. That demand comes from the likelihood of the debt  being repaid, and the rate of return people require to hold debt.

Second, if we have inflation, the mechanism will be very much like a run or debt crisis. Our government rolls over very short term debt. Roughly every two years on average, the government must find new lenders to pay off the old lenders. If new lenders sniff trouble they refuse to roll over the debt and we're suddenly in big trouble. This is what happened to Greece. It's what happened to Lehman Bros. In our case, our government can redeem debt with non-interest-paying reserves, resulting in a large inflation rather than an explicit default.

2a, a run is always unpredictable. If you knew there would be a roll-over crisis next year, you would dump your government bonds this year, and the run would be on. There is a whiff of multiple equilibrium too. Our debt is nicely sustainable at 1% interest. If interest rates go up to 5%, we suddenly have north of $1 trillion additional deficits, which are not sustainable. The government  is like a family who, buying a home, got the 0.1% adjustable rate mortgage rather than the 1% (government debt prices) fixed rate mortgage because it seemed cheaper. Then rates go up. A lot.

Sure demand is high for US government debt, rates are low, and there is no inflation. But don't count on trends to continue just because they are trends. How long does high demand last? Ask Greece. Ask an airline.

Third, for this reason, I argue the US should quickly move its debt to extremely long maturities. The best are perpetuities -- bonds that pay a fixed coupon forever, and have no principal payment. When the day of surpluses arrives, the government repurchases them at market prices. By replacing 300 ore more separate government bonds with three (fixed rate, floating rate, and indexed perpetuities), treasury markets would be much more liquid. Perpetuities never need to be rolled over. As you can imagine the big dealer banks hate the idea, and then wander off to reasons that make MMT sound like bells of clarity. That they would lose the opportunity to earn the bid/ask spread off the entire stock of US treasury debt as it is rolled over might just contribute.

But we don't have to wait for perpetuities. 30 year bonds would be a good start. 50 year bonds better. The treasury could tomorrow swap floating for fixed payments.

Then we would be like the family that got the 30 year fixed mortgage. Rates go up? We don't care. By funding long, the US could eliminate the possibility of a debt crisis, a rollover crisis, a sharp inflation for a generation. 

Magical Monetary Theory

I read Stephanie Kelton's book, The Deficit Myth: Modern Monetary Theory and the Birth of the People’s Economy,” and wrote this review for the Wall Street Journal. As usual I have to wait 30 days to post the whole thing here.

I approached this task with an open mind. What I had heard of MMT has some overlap with fiscal theory of the price level, on which I work, and I hoped to see some commonality.

I was disappointed. Short version:

"Ms. Kelton...starts with a few correct observations. But when the implications don’t lead to her desired conclusions, her logic, facts and language turn into pretzels." 

Full version in 30 days, if you can't find a way around WSJ paywall.

New paper: fiscal theory of monetary policy

A second new paper: "A fiscal theory of monetary policy with partially repaid long-term debt."

By "fiscal theory of monetary policy" I mean a model with standard DSGE ingredients, including inertemporal optimization and market clearing, monetary policy described by interest rate targets, price or other frictions, but closed by fiscal theory, "active" fiscal policy rather than "active" monetary policy.

I aim to build a standard simple but somewhat realistic model of this sort, a parallel to the three equation textbook model that has been part of the new-Keynesian tool kit since the 1990s. I keep the model as simple and standard as possible, so the effect of the innovations one the fiscal side are clearer.

Two parts of the specification are central. First, long-term debt allows the model to produce a negative response of inflation to interest rates. Long-term debt also allows a fiscal shock to result in a protracted inflation, which slowly devalues long term bonds, rather than a price level jump.

Second, and most important, the paper writes down a process for fiscal surpluses in which today's deficits are partially repaid by tomorrow's surpluses. Look quickly at the surplus response functions in my last post. When the government runs a deficit, it reliably runs subsequent surpluses that partially repay some of the accumulated debt. The surplus is not an AR(1)! It has an s-shaped response function.

So if you want a realistic fiscal theory model, you need a surplus with an s-shaped response function, but you need to keep "active" fiscal policy. This combination is the central innovation of the paper.