## Mixed Messages from The Fed and the Bond Markets

It’s conventional opinion that the Fed will begin to raise its policy rate by the end of 2015, and continue raising rates for the next couple years. In the FT, Larry Summers argues that this will be a mistake. And he observes that bond markets don’t seem to share the conventional wisdom: “Long term bond markets are telling us that real interest rates are expected to be close to zero in the industrialised world over the next decade.”

The Summers column inspired me to take a look at bond prices and flesh out this observation. It is straightforward to calculate how much the value of a bond change in response to a change in interest rates. So by looking at the current yields on bonds of different maturities, we can see what expectations of future rate changes are consistent with profit-maximizing behavior in bond markets. [1]

The following changes shows the yields of Treasury bonds of various maturities, and the capital loss for each bond from a one-point rise in yield over the next year. (All values are in percentage points.)

 Maturity Yield as of July 2015 Value Change from 1-Point Rise 30 year 3.07 -17.1 20 year 2.77 -13.9 10 year 2.32 -8.4 5 year 1.63 -4.6 1 year 0.30 -0.0

So if the 30-year rate rises by one point over the next year, someone who just bought a 30-year bond will suffer a 17 percent capital loss.

It’s clear from these numbers that Summers is right. If, over the next couple of years, interest rates were to “normalize” to their mid-90s levels (about 3 points higher than today), long bonds would lose half their value. Obviously, no one would hold bonds at today’s yields if they thought there was an appreciable chance of that happening.

We can be more precise. For any pair of bonds, the ratio of the difference in yields to the difference in capital losses from a rate increase, is a measure of the probability assigned by market participants to that increase. For example, purchasing a 20-year bond rather than a 30-year bond means giving up 0.3 percentage points of yield over the next year, in return for losing only 14 percent rather than 17 percent if there’s a general 1-point increase in rates. Whether that looks like a good or bad tradeoff will depend on how you think rates are likely to change.

For any pair of bonds, we can calculate the change in interest rates (across the whole yield curve) that would keep the overall return just equal between them. Using the average yields for July, we get:

30-year vs 20-year: +0.094%

30-year vs. 10-year: +0.086%

30-year vs. 5-year: +0.115%

20-year vs. 10-year +0.082%

20-year vs. 5 year: + 0.082%

Treasury bonds seem to be priced consistent with an expected tenth of a percent or so increase in interest rates over the next year.

In other words: If you buy a 30 year bond rather than a 20-year one, or a 20-year rather than 10-year, you will get a higher interest rate. But if it turns out that market rates rise by about 0.1 percentage points (10 basis points) over the next year, the greater capital losses on longer bonds will just balance their higher yields. So if you believe that interest rates in general will be about 10 basis points higher a year from now than they are now, you should be just indifferent between purchasing Treasuries of different maturities. If you expect a larger increase in rates, long bonds will look overpriced and you’ll want to sell them; if you expect a smaller increase in rates than this, or a decrease, then long bonds will look cheap to you and you’ll want to buy them. [2]

A couple of things to take from this.

First, there is the familiar Keynesian point about the liquidity trap. When long rates are low, even a modest increase implies very large capital losses for holders of long bonds. Fear of these losses can set a floor on long rates well above prevailing short rates. This, and not the zero lower bound per se, is the “liquidity trap” described in The General Theory.

Second,  compare the implied forecast of a tenth of a point increase in rates implied by today’s bond prices, to the forecasts in the FOMC dot plot. The median member of the FOMC expects an increase of more than half a point this year, 2 points by the end of 2016, and 3 points by the end of 2017. So policymakers at the Fed are predicting a pace of rate increases more than ten times faster than what seems to be incorporated into bond prices.

If the whole rate structure moves in line with the FOMC forecasts, the next few years will see the biggest losses in bond markets since the 1970s. Yet investors are still holding bonds at what are historically very low yields. Evidently either bond market participants do not believe that Fed will do what it says it will, or they don’t believe that changes in policy rate will have any noticeable effect on longer rates.

And note: The belief that long rates unlikely to change much, may itself prevent them from changing much. Remember, for a 30-year bond currently yielding 3 percent, a one point change in the prevailing interest rate leads to a 17 point capital loss (or gain, in the case of a fall in rates). So if you have even a moderately strong belief that 3 percent is the most likely or “normal” yield for this bond, you will sell or buy quickly when rates depart much from this. Which will prevent such departures from happening, and validate beliefs about the normal rate. So we shouldn’t necessarily expect to see the whole rate structure moving up and down together. Rather, long rates will stay near a conventional level (or at least above a conventional floor) regardless of what happens to short rates.

This suggests that we shouldn’t really be thinking about a uniform shift in the rate structure. (Though it’s still worth analyzing that case as a baseline.) Rather, an increase in rates, if it happens, will most likely be confined to the short end. The structure of bond yields seems to fit this prediction. As noted above, the yield curve at longer maturities implies an expected rate increase on the order of 10 basis points (a tenth of a percentage point), the 10-year vs 5 year, 10 year vs 1 year, and 5 year vs 1 year bonds imply epected increases of 18, 24 and 29 basis points respectively. This is still much less than dot plot, but it is consistent with idea that bond markets expect any rate increase to be limited to shorter maturities.

In short: Current prices of long bonds imply that market participants are confident that rates will not rise substantially over the next few years. Conventional wisdom, shared by policymakers at the Fed, says that they will. The Fed is looking at a two point increase over the next year and half, while bond rates imply that it will take twenty years. So either Fed won’t do what it says it will, or it won’t affect long rates, or bondholders will get a very unpleasant surprise. The only way everyone can be right is if trnasmission from policy rate to long rates is very slow — which would make the policy rate an unsuitable tool for countercyclical policy.

This last point is something that has always puzzled me about standard accounts of monetary policy. The central bank is supposed to be offsetting cyclical fluctuations by altering the terms of loan contracts whose maturities are much longer than typical business cycle frequencies. Corporate bonds average about 10 years, home mortgages, home mortgages of course close to 30. (And housing seems to be the sector most sensitive to policy changes.) So either policy depends on systematically misleading market participants, to convince them that cyclical rate changes are permanent; or else monetary policy must work in some completely different way than the familiar interest rate channel.

[1] In the real world things are more complicated, both because the structure of expectations is more complex than a scalar expected rate change over the next period, and because bonds are priced for their liquidity as well as for their return.

[2] I should insist in passing, for my brothers and sisters in heterodoxy, that this sort of analysis does not depend in any way on “consumers” or “households” optimizing anything, or on rational expectations. We are talking about real markets composed of profit-seeking investors, who certainly hold some expectations about the future even if they are mistaken.

## Five Thoughts on Monetary Policy

1. Monetary policy may operate on (a) the quantity of bank liabilities (money); (b) the quantity of bank assets (credit); (c) the price of one or more assets relative to money (an interest rate);  and/or (d) the price of money, normally relative to some other money (an exchange rate). Which of these should be considered the most immediate target of central bank policy, both practically and conceptually, has been debated for over 200 years. All four positions are well-represented in both academic literature and central bank policymaking. For the US over the past 50 years, you could say that the center of gravity — both in policy and in the economics profession — has shifted from the quantity of credit to the quantity of money, and then from the quantity of money to the price of credit. [*] I don’t know of any good historical account of these recent shifts, but they come through dramatically if you compare contemporary articles on monetary policy, ones from 20 years ago, and ones from 50 years ago.

Lance Taylor has a good discussion of the parallel debates in the 19th century on pages 68-84 of Maynard’s Revenge, and a somewhat more technical version in chapter 3 of Reconstructing Macroeconomics. Below, I reproduce his table classifying various early monetary theorists in the four categories above, and on the orthogonal dimension of whether the money/credit system is supposed to be active or passive with respect to the economy. Obviously, confidence about the usefulness of monetary policy implies a position on the lower half of the table.

 From Lance Taylor, Reconstructing Macroeconomics

It would be foolish to debate which of these positions is the correct one — though the monetarist view that the quantity of money plays an important causal role is clearly inapplicable to modern economies. It also seems possible that we may be seeing a shift away from the focus on the price of credit, and specifically the single policy interest rate — a position that is presented in many recent textbooks as the only possible one, even though it has been dominant only since the 1990s. In general what we should be doing is recognizing the diversity of positions and exploring the historical contexts in which one or another comes to dominate.

2. Regardless of which margin it operates on, monetary policy in its modern sense typically targets a level of aggregate output. This means changing how tightly liquidity constraints bind current expenditure. In other words, how easy is it for a unit that wants to increase its spending to acquire money, either by selling additional current output, selling an asset, or issuing a new liability? So regardless of the immediate target of monetary policy, the intermediate target is liquidity. (So what’s the point? The point is liquidity. The point is liquidity. The point is liquidity.) This may seem obvious, but keeping this idea in mind helps, I think, to cut through a lot of confusion. Expansionary policy makes it easier for someone to finance increased spending relative to income. Contractionary policy makes it harder.

3. Orthodox macroeconomics confuses the issue by assuming a world of infinite liquidity, where anyone can spend as much they like in any given period, subject to an intertemporal budget constraint that their spending over the infinite future must equal their income over that same infinite future. This condition — or equivalently the transversality or no-Ponzi condition — is coherent as a property of mathematical model. But  it is meaningless as applied to observable economic behavior. The only way my spending over my whole lifetime can be limited, is if my spending in some particular period is limited. Conversely, if I can spend as much as I want over any finite horizon, then logically I can spend as much as I want over an infinite horizon too. The orthodox solution is literally to just add an assumption saying “No you can’t,” without any explanation for where this limitation comes from. In reality, any financial constraint that rules out any trajectory of lifetime spending in excess of lifetime income will rule out some trajectories in which lifetime spending is less than lifetime income as well.

More concretely, orthodox theory approaches monetary policy through the lens of a consumption loan, in which the interest rate represents not the terms on which increased expenditure today can be financed, but the terms on which expenditure today trades off against expenditure in the future. In reality, consumption loans — while they do exist — are a very small fraction of total debt. The vast majority of private loans are taken to finance assets, which are expected to be income-positive. The models you find in graduate textbooks, in which the interest rate reflects a choice between consumption now and consumption later, have zero connection with real-world interest rates. The vast majority of loans are incurred to acquire an asset whose return will exceed the cost of the loan. So the expectation is that spending in the future will be higher, not lower, as a result of borrowing today. And of course nobody in the policy world believes in consumption loans or the interest rate as an intertemporal price or the intertemporal budget constraint or any of that. (Just compare Bernanke’s article on “The Credit Channel of Monetary Policy Transmission” with Woodford’s Interest and Prices, the most widely used New Keynesian graduate textbook. These are both “mainstream” economists, but there is zero conceptual overlap.) If you are not already stuck in the flybottle of academic economics there is no reason to worry about this stuff. Interest is not the price of consumption today vs. consumption tomorrow, it’s the price of money or of liquidity.

4. The fundamental tradeoff in the financial system is between flexibility and stability. The capacity of the financial system to delink expenditure from income is the whole point of it but also why it contributes to instability. Think of it this way: The same flexibility that allows an entrepreneur to ignore market signals to introduce a new product or process, allow someone to borrow money for a project that will never pay off. In general, it’s not clear until after the fact which is which. Monetary reforms respond to this tension by simultaneously aiming at making the system more rigid and at making it more flexible. This fundamental conflict is often obscured by the focus on specific mechanisms and by fact that same person often wants both. Go back to Hume, who opposed the use of bank-credit for payments and thought a perfect circulation was one in which the quantity of money was just equal to the amount of gold. But who also praised early banks for allowing merchants to “coin their whole wealth.”

You could also think of liquidity as providing a bridge for expenditure over dips in income. This is helpful when the fall is short-term — the existence of liquidity avoids unnecessary fluctuations in spending (and in aggregate income). But it is a problem when the fall is lasting — eventually, expenditure will have to confirm, and putting the adjustment off makes it larger and more disruptive when it comes. This logic is familiar in the business press, applied in particular, in a moralizing way, to public debt. But the problem is more general and doesn’t admit of a general solution. A more flexible credit system smooths over short-term fluctuations but allows more dangerous long-term imbalances to develop. A more rigid system prevents the development of any large imbalances but means you feel every little bump right up your spine.

(EDIT: On Twitter, Steve Randy Waldman points out that the above paragraph sits uncomfortably with my rejection of the idea of consumption loans. I should probably rewrite it.)
5. Politically, the fundamental fact about monetary policy is that it is central planning that cannot speak its name. The term “natural interest rate” was introduced by Wicksell, introduced to the English-speaking world by Hayek, and reintroduced by Friedman to refer specifically to the interest rate set by the central bank. It becomes necessary to assert that the interest rate is natural only once it is visibly a political question. And this isn’t only about the rhetoric of economics: Practical monetary policy continues to be constrained by the need for the outcome of policy choices to be disguised in this way.

Mike Konczal has a good discussion of how this need to maintain the appearance of “natural”market outcomes has hamstringed policy since 2008.

Starting in December 2012, the Federal Reserve started buying \$45 billion a month of long-term Treasuries. Part of the reason was to push down the interest rates on those Treasuries and boost the economy. But what if the Fed … had picked a price for long-term securities, and then figured out how much it would have to buy to get there? Then it would have said, “we aim to set the 10-year Treasury rate at 1.5 percent for the rest of the year” instead of “we will buy \$45 billion a month of long-term Treasuries.” This is what the Fed does with short-term interest rates…

What difference would this have made? The first is that it would be far easier to understand what the Federal Reserve was trying to do over time. … The second is that it might have been easier. … the markets are unlikely to go against the Fed … the third is that if low interest rates are the new normal, through secular stagnation or otherwise, these tools will need to be formalized. …

The normal economic argument against this is that all the action can be done with the short-rate. … the real argument is political. … the Federal Reserve would be accused of planning the economy by setting long-term interest rates. So it essentially has to sneak around this argument by adjusting quantities. … As Greta R. Krippner notes in her excellent Capitalizing on Crisis, in 1982 Frank Morris of the Boston Fed argued against ending their disaster tour with monetarism by saying, “I think it would be a big mistake to acknowledge that we were willing to peg interest rates again. The presence of an [M1] target has sheltered the central bank from a direct sense of responsibility for interest rates.”

I agree with Mike: The failure of the Fed to announce a price target for long bonds is a clear sign of the political limits to monetary policy. (Keynes, incidentally, came to support fiscal policy only after observing the same constraints on the Bank of England in the 1920s.) There is a profound ideological resistance to acknowledging that monetary policy is a form of planning. For a vivid example of this ideology in the wild, just go to the FRED website and look up the Federal Funds rate. Deciding on the level of the Fed Funds rate is the primary responsibility of the Federal Reserve, it’s the job of Janet Yellen and the rest of the FOMC. But according to the official documentation, this rate is “essentially determined by the market” and merely “influenced by the Federal Reserve.” There is a profound resistance, inscribed right in the data, to the idea that interest rates are consciously chosen consciously rather than somehow determined naturally in the market.

[*] This is a better description of the evolution of monetary theory than the evolution of monetary policy. It might be more accurate to say that policy went directly from targeting the quantity of credit to the price of credit, with the transitional period of attention to monetary aggregates just window dressing.

## Are US Households Done Deleveraging?

This Tuesday, I’ll be  at Joseph Stiglitz’s event at Columbia University on finance and inequality, presenting my work with Arjun Jayadev on household debt. You can find the latest version of our paper here.

In preparation, I’ve been updating the numbers and the results are interesting. As folks at the Fed have noted, the post-2007 period of household deleveraging seems to have reached its end. Here’s what the household debt picture looks like, in the accounting framework that Arjun and I prefer.

The units are percent of adjusted household income. (We can ignore the adjustments here.) The heavy black line shows the year-over-year change in household debt-income ratios. The bars then disaggregate that change into new borrowing by households — the primary deficit — and the respective contributions of interest payments, inflation, income growth, and defaults. A negative bar indicates a factor that reduces leverage; in most years, this includes both (real) income and inflation, since by raising the denominator they reduce the debt-income ratio. A positive bar indicates a factor that increases leverage; this includes interest payments (which are always positive), and the primary deficit in years in which households are on net receiving funds from credit markets.

Here’s what we are seeing:

In 2006 and 2007, debt-income ratios rose by about 3 percent each year; this is well below the six-point annual increases earlier in the 2000s, but still substantial. In 2008, the first year of the recession, the household debt-income ratio rises by another 3 points, despite the fact that households are now paying down debt, with repayments exceeding new borrowing by nearly 8 percent of household income. This is an astonishing rate of net repayment, the greatest since at least 1931. But despite this desperate effort to deleveraging, household debt-income ratios actually rose in 2008, thanks to the sharp fall in income and to near-zero inflation — in most years, the rise in prices automatically erodes the debt-income ratio. The combination of negative net borrowing and a rising debt burden is eerily reminiscent of the early Depression — it’s a clear sign of how, absent Big Government, the US at the start of the last recession was on track for a reprise of the Depression.

Interest payments make a stable positive contribution to the debt-incoem ratio throughout this period. Debt-service payments do fall somewhat, from around 7 percent of household income in 2006 to around 5 percent in 2013. But compared with other variables important to debt dynamics, debt-service payments are quite stable in the short-term. (Over longer periods, changes in effective interest rates are a ] bigger deal.) It’s worth noting in particular that the dramatic reduction in the federal funds rate in 2007-2008 had a negligible effect on the average interest rate paid by households.

In 2009-2012, the household debt-income ratio does fall, by around 5 points per year. But note that household surpluses (i.e. negative deficits) are no larger in these years than in 2008; the difference is that we see resumed positive growth of inflation and, a bit later, real incomes, raising the denominator of the debt-income ratio. This is what failed to happen in the 1930s. Equally important, there is a sharp rise in the share of debt written off by default, exceeding 3 percent in each year, compared with a writeoff rate below one percent in all pre-recession years. Note that the checked bar and the white bar are of similar magnitudes: In other words, repayment and default contributed about equally to the reduction of household debt. If deleveraging was an important requirement for renewed economic growth then it’s a good thing that it’s still possible to discharge our debts through bankruptcy. Otherwise, there would have been essentially no reduction in debt-income ratios between 2007 and 2012. [*]

This much is in the paper. But in 2013 the story changes a bit. The household debt-income ratio rises again, for the first time since 2008. And the household balance movers into deficit, for the first time since 2007 — for the first time in six years, households are receiving more funds from the credit markets than they are paying back to them. These events are linked. While the central point of our paper is that changes in leverage cannot be reduced to changes in borrowing, for the US households in 2013, it is in fact increased borrowing that drove the rise in debt-income ratios. Inflation and income growth were basically constant between 2012 and 2013. The 5-point acceleration in the growth of the household debt-income ratio is explained by a 4.5 point rise in new borrowing by households (plus a 1.5 point fall in defaults, offset by a 1-point acceleration in real income growth).

So what do we make of this? Well, first, boringly perhaps but importantly, it’s important to acknowledge that sometimes the familiar story is the correct story. If households owe more today than a year ago, it’s because they borrowed more over the past year. It’s profoundly misleading to suppose this is always the case. But in this case it is the case. Secondly, I think this vindicates the conclusion of our paper, that sustained deleveraging is impossible in the absence of substantially higher inflation, higher defaults, or lower interest rates. These are not likely to be seen without deliberate, imaginative policy to increase inflation, directly reduce the interest rates facing households, and/or write off much more of household debt than will happen through the existing bankruptcy process. Otherwise, in today’s low-inflation environment, as soon as the acute crisis period ends leverage is likely to resume its rise. Which seems to be what we are seeing.

[*] More precisely: By our calculations, defaults reduced the aggregate household debt-income ratio by 20 points over 2008-2012, out of a total reduction of 21.5 points.

## Alvin Hansen on Monetary Policy

The more you read in the history of macroeconomics and monetary theory, the more you find that current debates are reprises of arguments from 50, 100 or 200 years ago.

I’ve just been reading Perry Mehrling’s The Money Interest and the Public Interest, which  is one of the two best books I know of on this subject. (The other is Arie Arnon’s Monetary Theory and Policy Since David Hume and Adam Smith.) About a third of the book is devoted to Alvin Hansen, and it inspired me to look up some of Hansen’s writings from the 1940s and 50s. I was especially struck by this 1955 article on monetary policy. It not only anticipates much of current discussions of monetary policy — quantitative easing, the maturity structure of public debt, the need for coordination between the fiscal and monetary policy, and more broadly, the limits of a single interest rate instrument as a tool of macroeconomic management — but mostly takes them for granted as starting points for its analysis. It’s hard not to feel that macro policy debates have regressed over the past 60 years.

The context of the argument is the Treasury-Federal Reserve Accord of 1951, following which the Fed was no longer committed to maintaining fixed rates on treasury bonds of various maturities. [1] The freeing of the Fed from the overriding responsibility of stabilizing the market for government debt, led to scholarly and political debates about the new role for monetary policy. In this article, Hansen is responding to several years of legislative debate on this question, most recently the 1954 Senate hearings which included testimony from the Treasury department, the Fed Board’s Open Market Committee, and the New York Fed.

Hansen begins by expressing relief that none of the testimony raised

the phony question whether or not the government securities market is “free.” A central bank cannot perform its functions without powerfully affecting the prices of government securities.

He then expresses what he sees as the consensus view that it is the quantity of credit that is the main object of monetary policy, as opposed to either the quantity of money (a non-issue) or the price of credit (a real but secondary issue), that is, the interest rate.

Perhaps we could all agree that (however important other issues may be) control of the credit base is the gist of monetary management. Wise management, as I see it, should ensure adequate liquidity in the usual case, and moderate monetary restraint (employed in conjunction with other more powerful measures) when needed to check inflation. No doubt others, who see no danger in rather violent fluctuations in interest rates (entailing also violent fluctuations in capital values), would put it differently. But at any rate there is agreement, I take it, that the central bank should create a generous dose of liquidity when resources are not fully employed. From this standpoint the volume of reserves is of primary importance.

Given that the interest rate is alsoan object of policy, the question becomes, which interest rate?

The question has to be raised: where should the central bank enter the market -short-term only, or all along the gamut of maturities?

I don’t believe this is a question that economists asked much in the decades before the Great Recession. In most macro models I’m familiar with, there is simply “the interest rate,” with the implicit assumption that the whole rate structure moves together so it doesn’t matter which specific rate the monetary authority targets. For Hansen, by contrast, the structure of interest rates — the term and “risk” premiums — is just as natural an object for policy as the overall level of rates. And since there is no assumption that the whole structure moves together, it makes a difference which particular rate(s) the central bank targets. What’s even more striking is that Hansen not only believes that it matters which rate the central bank targets, he is taking part in a conversation where this belief is shared on all sides.

Obviously it would make little difference what maturities were purchased or sold if any change in the volume of reserve money influenced merely the level of interest rates, leaving the internal structure of rates unaffected. … In the controversy here under discussion, the Board leans toward the view that … new impulses in the short market transmit themselves rapidly to the longer maturities. The New York Reserve Bank officials, on the contrary, lean toward the view that the lags are important. If there were no lags whatever, it would make no difference what maturities were dealt in. But of course the Board does not hold that there are no lags.

Not even the most conservative pole of the 1950s debate goes as far as today’s New Keynesian orthodoxy that monetary policy can be safely reduced to the setting of a single overnight interest rate.

The direct targeting of long rates is the essential innovation of so-called quantitative easing. [2] But to Hansen, the idea that interest rate policy should directly target long as well as short rates was obvious. More than that: As Hansen points out, the same point was made by Keynes 20 years earlier.

If the central bank limits itself to the short market, and if the lags are serious, the mere creation of large reserves may not lower the long-term rate. Keynes had this in mind when he wrote: “Perhaps a complex offer by the central bank to buy and sell at stated prices gilt-edged bonds of all maturities, in place of the single bank rate for short-term bills, is the most important practical improvement that can be made in the technique of monetary management. . . . The monetary authority often tends in practice to concentrate upon short-term debts and to leave the price of long-term debts to be influenced by belated and imperfect re- actions from the price of short-term debts.” ‘ Keynes, it should be added, wanted the central bank to deal not only in debts of all maturities, but also “to deal in debts of varying degrees of risk,” i.e., high grade private securities and perhaps state and local issues.

That’s a quote from The General Theory, with Hansen’s gloss.

Fast-forward to 2014. Today we find Benjamin Friedman — one of the smartest and most interesting orthodox economists on these issues — arguing that the one great change in central bank practices in the wake of the Great Recession is intervention in a range of securities beyond the shortest-term government debt. As far as I can tell, he has no idea that this “profound” innovation in the practice of monetary policy was already proposed by Keynes in 1936. But then, as Friedman rightly notes, “Macroeconomics is a field in which theory lags behind experience and practice, not the other way around.”

Even more interesting, the importance of the rate structure as a tool of macroeconomic policy was recognized not only by the Federal Reserve, but by the Treasury in its management of debt issues. Hansen continues:

Monetary policy can operate on two planes: (1) controlling the credit base – the volume of reserve balances- and (2) changing the interest rate structure. The Federal Reserve has now backed away from the second. The Treasury emphasized in these hearings that this is its special bailiwick. It supports, so it asserts, the System’s lead, by issuing short- terms or long-terms, as the case may be, according to whether the Federal Reserve is trying to expand or contract credit … it appears that we now have (whether by accident or design) a division of monetary management between the two agencies- a sort of informal cartel arrangement. The Federal Reserve limits itself to control of the volume of credit by operating exclusively in the short end of the market. The Treasury shifts from short-term to long-term issues when monetary restraint is called for, and back to short-term issues when expansion is desired.

This is amazing. It’s not that Keynesians like Hansen  propose that Treasury should issue longer or shorter debt based on macroeconomic conditions. Rather, it is taken for granted that it does choose maturities this way. And this is the conservative side in the debate, opposed to the side that says the central bank should manage the term structure directly.

Many Slackwire readers will have recently encountered the idea that the maturities of new debt should be evaluated as a kind of monetary policy. It’s on offer as the latest evidence for the genius of Larry Summers. Proposing that Treasury should issue short or long term debt based on goals for the overall term structure of interest rates, and not just on minimizing federal borrowing costs, is the main point of Summers’ new Brookings paper, which has attracted its fair share of attention in the business press. No reader of that paper would guess that its big new idea was a commonplace of policy debates in the 1950s. [3]

Hansen goes on to raise some highly prescient concerns about the exaggerated claims being made for narrow monetary policy.

The Reserve authorities are far too eager to claim undue credit for the stability of prices which we have enjoyed since 1951. The position taken by the Board is not without danger, since Congress might well draw the conclusion that if monetary policy is indeed as powerful as indicated, nonmonetary measures [i.e. fiscal policy and price controls] are either unnecessary or may be drawn upon lightly.

This is indeed the conclusion that was drawn, more comprehensively than Hansen feared. The idea that setting an overnight interest rate is always sufficient to hold demand at the desired level has conquered the economics profession “as completely as the Holy Inquisition conquered Spain,” to coin a phrase. If you talk to a smart young macroeconomist today, you’ll find that the terms “aggregate demand was too low” and “the central bank set the interest rate too high” are used interchangeably. And if you ask, which interest rate?, they react the way a physicist might if you asked, the mass of which electron?

Faced with the argument that the inflation of the late 1940s, and price stability of the early 1950s, was due to bad and good interest rate policy respectively, Hansen offers an alternative view:

I am especially unhappy about the impli- cation that the price stability which we have enjoyed since February-March 1951 (and which everyone is justifiably happy about) could quite easily have been purchased for the entire postwar period (1945 to the present) had we only adopted the famous accord earlier …  The postwar cut in individual taxes and the removal of price, wage, and other controls in 1946 … did away once and for all with any really effective restraint on consumers. Under these circumstances the prevention of price inflation … [meant] restraint on investment. … Is it really credible that a drastic curtailment of investment would have been tolerated any more than the continuation of wartime taxation and controls? … In the final analysis, of course,  the then prevailing excess of demand was confronted with a limited supply of productive resources.

Inflation always comes down to this mismatch between “demand,” i.e. desired expenditure, and productive capacity.

Now we might say in response to such mismatches: Well, attempts to purchase more than we can produce will encourage increased capacity, and inflation is just a temporary transitional cost. Alternatively, we might seek to limit spending in various ways. In this second case, there is no difference of principle between an engineered rise in the interest rate, and direct controls on prices or spending. It is just a question of which particular categories of spending you want to hold down.

The point: Eighty years ago, Keynes suggested that what today is called quantitative easing should be a routine tool of monetary policy. Sixty years ago, Alvin Hansen believed that this insight had been accepted by all sides in macroeconomic debates, and that the importance of the term structure for macroeconomic activity guided the debt-issuance policies of Treasury as well as the market interventions of the Federal Reserve. Today, these seem like new discoveries. As the man says, the history of macroeconomics is mostly a great forgetting.

[1] I was surprised by how minimal the Wikipedia entry is. One of these days, I am going to start having students improve economics Wikipedia pages as a class assignment.

[2] What is “quantitative about this policy is that the Fed buys a a quantity of bonds, evidently in the hopes of forcing their price up, but does not announce an explicit target for the price. On the face of it, this is a strangely inefficient way to go about things. If the Fed announced a target for, say, 10-year Treasury bonds, it would have to buy far fewer of them — maybe none — since market expectations would do more of the work of moving the price. Why the Fed has hobbled itself in this way is a topic for another post.

[3] I am not the world’s biggest Larry Summers fan, to say the least. But I worry I’m giving him too hard a time in this case. Even if the argument of the paper is less original than its made out to be, it’s still correct, it’s still important, and it’s still missing from today’s policy debates. He and his coauthors have made a real contribution here. I also appreciate the Hansenian spirit in which Summers derides his opponents as “central bank independence freaks.”

## The Rentier Would Prefer Not to Be Euthanized

Here’s another one for the “John Bull can stand many things, but he cannot stand two percent” files. As Krugman says, there’s an endless series of these arguments that interest rates must rise. The premises are adjusted as needed to reach the conclusion. (Here’s another.) But what are the politics behind it?

I think it may be as simple as this: The rentiers would prefer not to be euthanized. Under capitalism, the elite are those who own (or control) money. Their function is, in a broad sense, to provide liquidity. To the extent that pure money-holders facilitate production, it is because money serves as a coordination mechanism, bridging gaps — over time and especially with unknown or untrusted counterparties — that would otherwise prevent cooperation from taking place. [1] In a world where liquidity is abundant, this coordination function is evidently obsolete and can no longer be a source of authority or material rewards.

More concretely: It may well be true that markets for, say, mortgage-backed securities are more likely to behave erratically when interest rates are very low. But in a world of low interest rates, what function do those markets serve? Their supposed purpose is to make it easier for people to get home loans. But in a world of very low interest rates, loans are, by definition, easy to get. Again, with abundant liquidity, stocks may get bubbly. But in a world of abundant liquidity, what problem is the existence of stock markets solving? If anyone with a calling to run a business can readily start one with a loan, why support a special group of business owners? Yes, in a world where bearing risk is cheap, specialist risk-bearers are likely to go a bit nuts. But if risk is already cheap, why are we employing all these specialists?

The problem is, the liquidity specialists don’t want to go away. From finance’s point of view, permanently low interest rates are removing their economic reason for being — which they know eventually is likely to remove their power and privileges too. So we get all these arguments that boil down to: Money must be kept scarce so that the private money-sellers can stay in business.

It’s a bit like Dr. Benway in Naked Lunch:

“Now, boys, you won’t see this operation performed very often and there’s a reason for that…. You see it has absolutely no medical value. No one knows what the purpose of it originally was or if it had a purpose at all. Personally I think it was a pure artistic creation from the beginning.

“Just as a bull fighter with his skill and knowledge extricates himself from danger he has himself invoked, so in this operation the surgeon deliberately endangers his patient, and then, with incredible speed and celerity, rescues him from death at the last possible split second….

Interestingly, Dr. Benway was worried about technological obsolescence too. “Soon we’ll be operating by remote control on patients we never see…. We’ll be nothing but button pushers,” etc. The Dr. Benways of finance like to fret about how robots will replace human labor. I wonder how much of that is a way of hiding from the knowledge that what cheap and abundant capital renders obsolete, is the capitalist?

EDIT: I’m really liking the idea of Larry Summers as Dr. Benway. It fits the way all the talk when he was being pushed for Fed chair was about how great he would be in a financial crisis. How would everyone known how smart he was — how essential — if he hadn’t done so much to create a crisis to solve?

[1] Capital’s historic role as a facilitator of cooperation is clearly described in chapter 13 of Capital.

## Boulding on Interest

Kenneth Boulding, reviewing Maurice Allais’s  Économie et intérêt in 1951:

Much work on the theory of interest is hampered at the start by its unquestioned assumption that “the” rate of interest, or even some complex of rates, is a suitable parameter for use in the construction of systems of economic relationships, whether static or dynamic. This is an assumption which is almost universally accepted and yet which seems to me to be very much open to question. My reason for questioning it is that the rate of interest is not an objective magnitude… The rate of interest is not a “price”; its dimensions are those of a rate of growth, not of a ratio of exchange, even though it is sometimes carelessly spoken of as a “price of loanable funds.” What is determined in the market is not strictly the rate of interest but the price of certain “property rights.” These may be securities, either stocks or bonds, or they may be items or collections of physical property. Each of these property rights represents to an individual an expected series of future values, which may be both positive and negative. If this expected series of values can be given some “certainty equivalent” … then the market price of the property determines a rate of interest on the investment. This rate of interest, however, is essentially subjective and depends on the expectations of the individual; the objective phenomenon is the present market price

It is only the fact that the fulfilment of some expectations seems practically certain that gives us the illusion that there is an objective rate of interest determined in the market. But in strict theory there is no such certainty, even for gilt-edged bonds; and when the uncertainties of life, inflation, and government are taken into consideration, it is evident that this theoretical uncertainty is also a matter of practice. What is more, we cannot assume either that there are any “certain equivalents” of uncertain series for it is the very uncertainty of the future which constitutes its special quality. What this means is that it is quite illegitimate even to begin an interest theory by abstracting from uncertainty or by assuming that this can be taken care of by some “risk premium”; still less is it legitimate to construct a whole theory on these assumptions … without any discussion of the problems which uncertainty creates. What principally governs the desired structure of assets on the part of the individual is the perpetual necessity to hedge — against inflation, against deflation, against the uncertainty in the future of all assets, money included. It is these uncertainties, therefore, which are the principal governors of the demand and supply of all assets without exception, and no theory which abstracts from these uncertainties can claim much significance for economics. Hence, Allais is attempting to do something which simply cannot be done, because it is meaningless to construct a theory of “pure” interest devoid of premiums for risk, liquidity, convenience, amortization, prestige, etc. There is simply no such animal.

In other words: There are contexts when it is reasonable to abstract from uncertainty, and proceed on the basis that people know what will happen in the future, or at least its probability distribution. But interest rates are not such a context, you can’t abstract away from uncertainty there. Because compensation for uncertainty is precisely why interest is paid.

The point that what is set in the market, and what we observe, is never an interest rate as such, but the price of some asset today in terms of money today, is also important.

Boulding continues:

The observed facts are the prices of assets of all kinds. From these prices we may deduce the existence of purely private rates of return. The concept of a historical “yield” also has some validity. But none of these things is a “rate of interest” in the sense of something determined in a market mechanism.

This search for a black cat that isn’t there leads Allais into several extended discussions of almost meaningless and self-constructed questions… Thus he is much worried about the “fact” that a zero rate of interest means an infinite value for land, land representing a perpetual income, which capitalized at a zero rate of interest yields an infinite value… This is a delightful example of the way in which mathematics can lead to an almost total blindness to economic reality. In fact, the income from land is no more perpetual than that from anything else and no more certain. … We might draw a conclusion from this that a really effective zero rate of interest in a world of perfect foresight would lead to an infinite inflation; but, then, perfect foresight would reduce the period of money turnover to zero anyway and would give us an infinite price level willy-nilly! This conclusion is interesting for the light it throws on the complete uselessness of the “perfect foresight” model but for little else. In fact, of course, the element which prevents both prices from rising to infinity and (private) money rates of interest from falling to zero is uncertainty – precisely the factor which Allais has abstracted from. Another of these quite unreal problems which worries him a great deal is why there is always a positive real rate of interest, the answer being of course that there isn’t! …

Allais reflects also another weakness of “pure”interest theory, which is a failure to appreciate the true significance and function of financial institutions and of “interest” as opposed to “profit” – interest in this sense being the rate of growth of value in “securities,” especially bonds, and “profit” being the rate of growth of value of items or combinations of real capital. Even if there were no financial institutions or financial instruments … there would be subjective expected rates of profit and historical yields on past, completed investments. In such a society, however, given the institution of private property, everyone would have to administer his own property. The main purpose of the financial system is to separate “ownership” (i.e., equity) from “control,” or administration, that is, to enable some people to own assets which they do not control, and others to control assets which they do not own. This arrangement is necessitated because there is very little, in the processes by which ownership was historically determined through inheritance and saving, to insure that those who own the resources of society are … capable of administering them. Interest, in the sense of an income received by the owners of securities, is the price which society pays for correcting a defect in the otherwise fruitful institution of private property. It is, of course, desirable that the price should be as small as possible – that is, that there should be as little economic surplus as possible paid to nonadministering owners. It is quite possible, however, that this “service” has a positive supply price in the long run, and thus that, even in the stationary state, interest, as distinct from profit, is necessary to persuade the nonadministering owners to yield up the administration of their capital.

This last point is important, too. Property, we must always remember, is not a relationship between people and things. it is a relationship between people and people. Ownership of an asset means the authority to forbid other people from engaging in a certain set of productive activities. The “product” of the asset is how much other people will pay you not to exercise that right. Historically, of course, the sets of activities associated with a given asset have often been defined in relation to some particular means of production. But this need not be the case. In a sense, the patent or copyright isn’t an extension of the idea of property, but property in its pure form. And even where the rights of an asset owner are defined as those connected with some tangible object, the nature of the connection still has to be specified by convention and law.

According to Wikipedia, Économie et intérêt,  published in 1947, introduced a number of major ideas in macroeconomics a decade or more before the American economists they’re usually associated with, including the overlapping generations model and the golden rule for growth. Boulding apparently did not find these contributions worth mentioning. He does, though, have something to say about Allais’s “economic philosophy” which “is a curious combination of Geseel, Henry George and Hayek,” involving “free markets, with plenty of trust- and union-busting, depreciating currency, and 100 per cent reserves in the banking system, plus the appropriation of all scarcity rents and the nationalization of land.” Boulding describes this as “weird enough to hit the jackpot.” It doesn’t seem that weird to me. It sounds like a typical example of a political vision you can trace back to Proudhon and forward through the “Chicago plan” of the 1930s and its contemporary admirers to the various market socialisms and more or less crankish monetary reform plans. (Even Hyman Minsky was drawn to this strain of politics, according to Perry Mehrling’s superb biographical essay.)What all these have in common is that they see the obvious inconsistency between capitalism as we observe it around us and the fairy tales of ideal market exchange, but they don’t reject the ideal. Instead, they propose a program of intrusive regulations to compel people to behave as they are supposed to in an unregulated market. They want to make the fairy tales true by legislation. Allais’ proposal for currency depreciation is not normally part of this package; it’s presumably a response to late-1940s conditions in France. But other than that these market utopias are fairly consistent. In particular, it’s always essential to reestablish the objectivity of money.

Finally, in a review full of good lines, I particularly like this one:

Allais’s work is another demonstration that mathematics and economics, though good complements, are very imperfect substitutes. Mathematics can manipulate parameters once formulated and draw conclusions out which were already implicit in the assumptions. But skills of the mathematician are no substitute for the proper skill of the economist, which is that of selecting the most significant parameters to go into the system.

## Where Do Interest Rates Come From?

What determines the level of interest rates? It seems like a simple question, but I don’t think economics — orthodox or heterodox — has an adequate answer.

One problem is that there are many different interest rates. So we have two questions: What determines the overall level of interest rates, and what determines the spreads between different interest rates? The latter in turn we can divide into the question of differences in rates between otherwise similar loans of different lengths (term spreads), differences in rates between otherwise similar loans denominated in different currencies, and all the remaining differences, grouped together under the possibly misleading name risk spreads.

In any case, economic theory offers various answers:

1. The orthodox answer, going back to the 18th century, is that the interest rate is a price that equates the desire to save with the desire to borrow. As reformulated in the later 19th century by Bohm-Bawerk, Cassel, etc., that means: The interest rate is the price of goods today relative to goods tomorrow. The interest rate is the price that balances the gains from deferring consumption with our willingness to do so. People generally prefer consumption today to consumption in the future, and because it will be possible to produce more in the future than today, so the interest rate is (normally) positive. This is a theory of all transactions that exchange spending in one period for spending (or income) in another, not specifically a theory of the interest rate on loans.

The Wicksell variant of this, which is today’s central-bank orthodoxy, is that there is a well-defined natural interest rate in this sense but that for some reason markets get this one price wrong.

2. An equally old idea is that the interest rate is the price of money. In Hume’s writings on money and interest, for instance, he vacillates between this and the previous story. It’s not a popular view in the economics profession but it’s well-represented in the business world and among populists and monetary reformers,. In this view, money is just another input to the production process, and the interest rate is its price. A creditor, in this view, isn’t someone deferring consumption to the future, but someone who — like a landlord — receives an income thanks to control of a necessary component of the production process. A business, let’s say, that needs to maintain a certain amount of working capital in the form of money or similarly liquid assets, may need to finance it with a loan on which it pays interest. Interest payments are in effect the rental price of money, set by supply and demand like anything else. As I say, this has never been a respectable view in economic theory, but you can find it in more empirical work, like this paper by Gabriel Chodorow-Reich, where credit is described in exactly these terms as an input to current production.

3. Keynes’ liquidity-preference story in The General Theory. Here again the interest rate is the price of money. But now instead of asking how much the marginal business borrower will pay for the use of money, we ask how much the marginal wealth owner needs to be compensated to give up the liquidity of money for a less-liquid bond. The other side of the market is given by a fixed stock of bonds; evidently we are dealing with a short enough period that the flow of new borrowing can be ignored, and the bond stock treated as exogenously fixed. With no new borrowing, the link from the interest rate is liked to the real economy because it is used to discount the expected flow of profits from new investment — not by business owners themselves, but by the stock market. It’s an oddly convoluted story.

4. A more general liquidity-preference story. Jorg Bibow, in a couple of his essential articles on the Keynesian theory of liquidity preference, suggests that many of the odd features of the theory are due to Keynes’ decision to drop the sophisticated analysis of the financial system from The Treatise on Money and replace it with an assumption of an exogenously fixed money stock. (It’s striking that banks play no role in in the General Theory.) But I’m not sure how much simpler this “simplification” actually makes the story, or whether it is even logically coherent; and in any case it’s clearly inapplicable to our modern world of bank-created credit money. In principle, it should be possible to tell a more general version of the liquidity preference story, where, instead of wealth holders balancing the income from holding a bond against the liquidity from holding “money,” you have banks balancing net income against incremental illiquidity from simultaneously extending a loan and creating a deposit. I’m afraid to say I haven’t read the Treatise, so I don’t know how much you can find that story there. In any case it doesn’t seem to have been developed systematically in later theories of endogenous money, which typically assume that the supply of credit is infinitely elastic except insofar as it’s limited by regulation.

5. The interest rate is set by the central bank. This is the orthodox story when we turn to the macro textbook. It’s also the story in most heterodox writers. From Wicksell onward, the whole discussion about interest rates in a macroeconomic context is about how the central bank can keep the interest rate at the level that keeps current expenditure at the appropriate level, and what happens if it fails to do so. It is sometimes suggested that the optimal or “natural” interest rate chosen by the central bank should be the the Walrasian intertemporal exchange rate — explicitly by Hayek, Friedman and sometimes by New Keynesians like Michael Woodford, and more cautiously by Wicksell. But the question of how the central bank sets the interest rate tends to drop out of view. Formally, Woodford has the central bank set the interest rate by giving it a monopoly on lending and borrowing. This hardly describes real economies, of course, but Woodford insists that it doesn’t matter since central banks could control the interest rate by standing ready to lend or borrow unlimited amounts at thresholds just above and below their target. The quite different procedures followed by real central banks are irrelevant. [1]

A variation of this (call it 5a) is where reserve requirements bind and the central bank sets the total quantity of bank credit or money. (In a world of bind reserve requirements, these will be equivalent.) In this case, the long rate is set by the demand for credit, given the policy-determined quantity. The interbank rate is then presumably bid up to the minimum spread banks are willing to lend at. In this setting causality runs from long rates to short rates, and short rates don’t really matter.

6. The interest rate is set by convention. This is Keynes’ other theory of the interest rate, also introduced in the General Theory but more fully developed in his 1937 article “Alternative Theories of the Rate of Interest.” The idea here is that changes in interest rates imply inverse changes in the price of outstanding bonds. So from the lenders’ point of view, the expected return on a loan includes not only the yield (as adjusted for default risk), but also the capital gain or loss that will result if interest rates change while the loan is still on their books. The longer the term of the loan, the larger these capital gains or losses will be. I’ve discussed this on the blog before and may come back to it in the future, but the essential point is that if people are very confident about the future value of long rates (or at least that they will not fall below some floor) then the current rate cannot get very far from that future expected rate, no matter what short rates are doing, because as the current long rate moves away from the expected long rate expected capital gains come to dominate the current yield. Take the extreme case of a perpetuity where market participants are sure that the rate will be 5% a year from now. Suppose the short rate is initially 5% also, and falls to 0. Then the rate on the perpetuity will fall to just under 4.8% and no lower, because at that rate the nearly 5% spread over the short rate just compensates market participants for the capital loss they expect when long rates return to their normal level. (Obviously, this is not consistent with rational expectations.) These kinds of self-stabilizing conventional expectations are the reason why, as Bibow puts it, “a liquidity trap … may arise at any level of interest.” A liquidity trap is an anti-bubble, if you like.

What do we think about these different stories?

I’m confident that the first story is wrong. There is no useful sense in which the interest rate on debt contracts — either as set by markets or as target by the central bank — is the price of goods today in terms of goods tomorrow. The attempt to understand interest rates in terms of the allocation across time of scarce means to alternative ends is a dead end. Some other intellectual baggage that should overboard with the “natural” rate of interest are the “real”rate of interest, the idea of consumption loans, and the intertemporal budget constraint.

But negative criticism of orthodoxy is too easy. The real work is to make a positive case for an alternative. I don’t see a satisfactory one here.

The second and third stories depend on the existence of “money” as a distinct asset with a measurable, exogenously fixed quantity. This might be a usable assumption in some historical contexts — or it might not — but it clearly does not describe modern financial systems. Woodford is right about that.

The fifth story is clearly right with respect short rates, or at least it was until recently. But it’s incomplete. As an empirical matter, it is true that interbank rates and similar short market rates closely follow the policy rate. The question is, why? The usual answer is that the central bank is the monopoly supplier of base money, and base money is used for settlement between banks. This may be so, but it doesn’t have to be. Plenty of financial systems have existed without central banks, and banks still managed to make payments to each other somehow. And where central banks exist, they don’t always have a monopoly on interbank settlement. During the 19th century, the primary tool of monetary policy at the Bank of England was the discount rate — the discount off of face value that the bank would pay for eligible securities (usually trade credit). But if the discount rate was too high — if the bank offered too little cash for securities — private banks would stop discounting securities at the central bank, and instead find some other bank that was willing to give them cash on more favorable terms. This was the problem of “making bank rate effective,” and it was a serious concern for 19th century central banks. If they tried to raise interest rates too high, they would “lose contact with the market” as banks simply went elsewhere for liquidity.

Obviously, this isn’t a problem today — when the Fed last raised policy rates in the mid-2000s, short market rates rose right along with it. Or more dramatically, Brazil’s central bank held nominal interest rates around 20 percent for nearly a decade, while inflation averaged around 8 percent. [2] In cases like these, the central bank evidently is able to keep short rates high by limiting the supply of reserves. But why in that case doesn’t the financial system develop private substitutes for reserves? Mervyn King blandly dismisses this question by saying that “it does not matter in principle whether the disequilibrium in the money market is an aggregate net shortage or a net surplus of funds—control of prices or quantities carries across irrespective of whether the central bank is the monopoly supplier or demander of its own liabilities.” [3] Clearly, the central bank cannot be both the monopoly supplier and the monopoly demander of reserves, at least not if it wants to have any effect on the rest of the world. The relevant question — to which King offers no answer — is why there are no private substitutes for central bank reserves. Is it simply a matter of legal restrictions on interbank settlements using any other asset? But then why has this one regulatory barrier remained impassable while banks have tunneled through so many others? Anyway, going forward the question may be moot if reserves remain abundant, as they will if the Fed does not shrink its balance sheet back to pre-crisis levels. In that case, new tools will be required to make the policy rate effective.

The sixth story is the one I’m most certain of. First, because it can be stated precisely in terms of asset market equilibrium. Second, because it is consistent with what we see historically. Long term interest rates are quite stable over very long periods. Third, it’s consistent with what market participants say: It’s easy to find bond market participants saying that some rate is “too low” and won’t continue, regardless of what the Fed might think. Last, but not least from my point of view, this view is clearly articulated by Keynes and by Post Keynesians like Bibow. But while I feel sure this is part of the story, it can’t be the whole story. First, because even if a conventional level of interest rates is self-stabilizing in the long run, there are clearly forces of supply and demand in credit markets that push long rates away from this level in the short run. This is even more true if what convention sets is less a level of interest rates, than a floor. And second, because Keynes also says clearly that conventions can change, and in particular that a central bank that holds short rates outside the range bond markets consider reasonable for long enough, will be able to change the definition of reasonable. So that brings us back to the question of how it is that central banks are able to set short rates.

I think the fundamental answer lies behind door number 4. I think there should be a way of describing interest rates as the price of liquidity, where liquidity refers to the capacity to honor one’s promises, and not just to some particular asset. In this sense, the scarce resource that interest is pricing is trust. And monetary policy then is at root indistinguishable from the lender of last resort function — both are aspects of the central bank’s role of standing in as guarantor for commitments within the financial system.  You can find elements of this view in the Keynesian literature, and in earlier writers going back to Thornton 200-plus years ago. But I haven’t seen it stated systematically in way that I find satisfactory.

UPDATE: For some reason I brought up the idea of the interest rate as the price of money without mentioning the classic statement of this view by Walter Bagehot. Bagehot uses the term “price of money” or “value of money” interchangeably with “discount rate” as synonyms for the interest rate. The discussion in chapter 5 of Lombard Street is worth quoting at length:

Many persons believe that the Bank of England has some peculiar power of fixing the value of money. They see that the Bank of England varies its minimum rate of discount from time to time, and that, more or less, all other banks follow its lead, and charge much as it charges; and they are puzzled why this should be. ‘Money,’ as economists teach, ‘is a commodity, and only a commodity;’ why then, it is asked, is its value fixed in so odd a way, and not the way in which the value of all other commodities is fixed?

There is at bottom, however, no difficulty in the matter. The value of money is settled, like that of all other commodities, by supply and demand… A very considerable holder of an article may, for a time, vitally affect its value if he lay down the minimum price which he will take, and obstinately adhere to it. This is the way in which the value of money in Lombard Street is settled. The Bank of England used to be a predominant, and is still a most important, dealer in money. It lays down the least price at which alone it will dispose of its stock, and this, for the most part, enables other dealers to obtain that price, or something near it. …

There is, therefore, no ground for believing, as is so common, that the value of money is settled by different causes than those which affect the value of other commodities, or that the Bank of England has any despotism in that matter. It has the power of a large holder of money, and no more. Even formerly, when its monetary powers were greater and its rivals weaker, it had no absolute control. It was simply a large corporate dealer, making bids and much influencing—though in no sense compelling—other dealers thereby.

But though the value of money is not settled in an exceptional way, there is nevertheless a peculiarity about it, as there is about many articles. It is a commodity subject to great fluctuations of value, and those fluctuations are easily produced by a slight excess or a slight deficiency of quantity. Up to a certain point money is a necessity. If a merchant has acceptances to meet to-morrow, money he must and will find today at some price or other. And it is this urgent need of the whole body of merchants which runs up the value of money so wildly and to such a height in a great panic….

If money were all held by the owners of it, or by banks which did not pay an interest for it, the value of money might not fall so fast. … The possessors would be under no necessity to employ it all; they might employ part at a high rate rather than all at a low rate. But in Lombard Street money is very largely held by those who do pay an interest for it, and such persons must employ it all, or almost all, for they have much to pay out with one hand, and unless they receive much with the other they will be ruined. Such persons do not so much care what is the rate of interest at which they employ their money: they can reduce the interest they pay in proportion to that which they can make. The vital point to them is to employ it at some rate…

The fluctuations in the value of money are therefore greater than those on the value of most other commodities. At times there is an excessive pressure to borrow it, and at times an excessive pressure to lend it, and so the price is forced up and down.

The relevant point in this context is the explicit statement that the interest, or discount, rate is set by the supply and demand for money. But there are a couple other noteworthy things. First, the concept of supply and demand is one of monopolistic competition, in which lenders are not price takers, but actively trade off markup against market share. And second, that the demand for money (i.e. credit) is highly inelastic because money is needed not only or mainly to purchase goods and services, but first and foremost to meet contractual money commitments.

[1] See Perry Mehrling’s useful review. Most of the text of Woodford’s textbook can be downloaded for free here. The introduction is nontechnical and is fascinating reading if you’re interested in this stuff.

[2] Which is sort of a problem for Noah Smith’s neo-Fisherite view.

[3] in the same speech, King observes that “During the 19th century, the Bank of England devoted considerable attention to making bank rate ‘effective’.” His implication is that central banks have always been able to control interest rates. But this is somewhat misleading, from my point of view: the Bank devoted so much attention to making its rate “effective” precisely because of the occasions when it failed to do so.

## Liquidity Preference and Solidity Preference in the 19th Century

So I’ve been reading Homer and Sylla’s History of Interest Rates. One of the many fascinating things I’ve learned, is that in the market for federal debt, what we today call an inverted yield curve was at one time the norm.

From the book:

Three small loans floated in 1820–1821, principally to permit the continued redemption of high rate war loans, provide an interesting clue to investor preference… These were:

\$4.7 million “5s of 1820,” redeemable in 1832; sold at 100 = 5%.
“6s of 1820,” redeemable at pleasure of United States; sold at 102 = 5.88%.
“5s of 1821,” redeemable in 1835; sold at 1051⁄8 =4.50%, and at 108 = 4.25%.

The yield was highest for the issue with early redemption risk and much lower for those with later redemption risks.

Nineteenth century government bonds were a bit different from modern bonds, in that the principal was repaid at the option of the borrower; repayment is usually not permitted until a certain date. [1] They were also sold with a fixed yield in terms of face value — that’s what the “5” and “6” refer to — but the actual yield depended on the discount or premium they were sold at. The important thing for our purposes is that the further away the earliest possible date of repayment is, the lower the interest rate — the opposite of the modern term premium. That’s what the passage above is saying.

The pattern isn’t limited to the 1820-21 bonds, either; it seems to exist through most of the 19th century, at least for the US. It’s the same with the massive borrowing during the Civil War:

In 1864, although the war was approaching its end, it had only been half financed. The Treasury was able to sell a large volume of bonds, but not at such favorable terms as the market price of its seasoned issues might suggest. Early in the year another \$100 million of the 5–20s [bonds with a minimum maturity of 5 years and a maximum of 20] were sold and then a new longer issue was sold as follows:

1864—\$75 million “6s”  redeemable in 1881, tax-exempt; sold at 104.45 = 5.60%.

The Treasury soon made an attempt to sell 5s, which met with a lukewarm reception. In order to attract investors to the lower rate the Treasury extended the term to redemption from five to ten years and the maturity from twenty to forty years

1864—\$73 million “5%, 10–40s of 1864,” redeemable 1874, due in 1904, tax-exempt; sold at 100 = 5%.

Isn’t that striking? The Treasury couldn’t get investors to buy its shorter bonds at an acceptable rate, so they had to issue longer bonds instead. You wouldn’t see that story today.

The same pattern continues through the 1870s, with the new loans issue to refinance the Civil War debt. The first issue of bonds, redeemable in five to ten years sold at an interest rate of 5%; the next issue, redeemable in 13-15 years sold at 4.5%; and the last issue, redeemable in 27-29 years, sold at 4%. And it doesn’t seem like this is about expectations of a change in rates, like with a modern inverted yield curve. Investors simply were more worried about being stuck with uninvestable cash than about being stuck with unsaleable securities. This is a case where “solidity preference” dominates liquidity preference.

One possible way of explaining this in terms of Axel Leijonhufvud’s explanation of the yield curve.

The conventional story for why long loans normally have higher interest rates than short ones is that longer loans impose greater risks on lenders. They may not be able to convert the loan to cash if they need to make some payment before it matures, and they may suffer a capital loss if interest rates change during the life of the loan. But this can’t be the whole story, because short loans create the symmetric risk of not knowing what alternative asset will be available when the loan matures. In the one case, the lender risks a capital loss, but in the other case they risk getting a lower income. Why is “capital uncertainty” a greater concern than “income uncertainty”?

The answer, Leijonhufvud suggests, lies in

Keynes’ … “Vision” of a world in which currently active households must, directly or indirectly, hold their net worth in the form of titles to streams that run beyond their consumption horizon. The duration of the relevant consumption plan is limited by the sad fact that “in the Long Run, we are all dead.” But the great bulk of the “Fixed Capital of the modem world” is very long- term in nature and is thus destined to survive the generation which now owns it. This is the basis for the wealth effect of changes in asset values.

The interesting point about this interpretation of the wealth effect is that it also provides a price-theoretical basis for Keynes’ Liquidity Preference theory. … Keynes’ (as well as Hicks’) statement of this hypothesis has been repeatedly criticized for not providing any rationale for the presumption that the system as a whole wants to shed “capital uncertainty” rather than “income uncertainty.” But Keynes’ mortal consumers cannot hold land, buildings, corporate equities, British consols, or other permanent income sources “to maturity.” When the representative, risk-averting transactor is nonetheless induced by the productivity of roundabout processes to invest his savings in such income sources, he must be resigned to suffer capital uncertainty. Forward markets will therefore generally show what Hicks called a “constitutional weakness” on the demand side.

I would prefer not to express this in terms of households’ consumption plans. And I would emphasize that the problem with wealth in the form of long-lived production processes is not just that it produces income far into the future, but that wealth in this form is always in danger of losing its character as money. Once capital is embodied in a particular production process and the organization that carries it out, it tends to evolve into the means of carrying out that organization’s intrinsic purposes, instead of the capital’s own self-expansion. But for this purpose, the difference doesn’t matter; either way, the problem only arises once you have, as Leijonhufvud puts it, “a system ‘tempted’ by the profitability of long processes to carry an asset stock which turns over more slowly than [wealth owners] would otherwise want.”

The temptation of long-lived production processes is inescapable in modern economies, and explains the constant search for liquidity. But in the pre-industrial United States? I don’t think so. Long-lived means of production were much less important, and to the extent they did exist, they weren’t an outlet for money-capital. Capital’s role in production was to finance stocks of raw materials, goods in process and inventories. There was no such thing, I don’t think, as investment by capitalists in long-lived capital goods. And even land — the long-lived asset in most settings — was not really an option, since it was abundant. The early United States is something like Samuelson’s consumption-loan world, where there is no good way to convert command over current goods into future production. [2] So there is excess demand rather than excess supply for long-lasting sources of income.

The switch over to positive term premiums comes early in the 20th century. By the 1920s, short-term loans in the New York market consistently have lower rates than corporate bonds, and 3-month Treasury bills have rates below longer bonds. Of course the organization of financial markets changed quite a lot in this period too, so one wouldn’t want to read too much into this timing. But it is at least consistent with the Leijonhufvud story. Liquidity preference becomes dominant in financial markets only once there has been a decisive shift toward industrial production by long-lived firm using capital-intensive techniques, and once claims on those firms has become a viable outlet for money-capital.

* * *

A few other interesting points about 19th century US interest rates. First, they were remarkably stable, at least before the 1870s. (This fits with the historical material on interest rates that Merijn Knibbe has been presenting in his excellent posts at Real World Economics Review.)

Second, there’s no sign of a Fisher equation. Nominal interest rates do not respond to changes in the price level, at all. Homer and Sylla mention that in earlier editions of the book, which dealt less with the 20th century, the concept of a “real” interest rate was not even mentioned.

As you can see from this graph, none of the major inflations or deflations between 1850 and 1960 had any effect on nominal interest rates. The idea that there is a fundamentals-determined “real” interest rate while the nominal rate adjusts in response to changes in the price level, clearly has no relevance outside the past 50 years. (Whether it describes the experience of the past 50 years either is a question for another time.)

Finally, there is no sign of “crowding out” of private by public borrowing. It is true that the federal government did have to pay somewhat higher rates during the periods of heavy borrowing (and of course also political uncertainty) in the War of 1812 and the Civil War. But rates for other borrowers didn’t budge. And on the other hand, the surpluses that resulted in the redemption of the entire debt in the 1830s didn’t deliver lower rates for other borrowers. Homer and Sylla:

Boston yields were about the same in 1835, when the federal debt was wiped out, as they were in 1830; this reinforces the view that there was little change in going rates of long-term interest during this five- year period of debt redemption.

If government borrowing really raises rates for private borrowers, you ought to see it here, given the absence of a central bank for most of this period and the enormous scale of federal borrowing during the Civil War. But you don’t.

[1] It seems that most, though not all, bonds were repaid at the earliest possible redemption date, so it is reasonably similar to the maturity of a modern bond.

[2] Slaves are the big exception. So the obvious test for the argument I am making here would be to find the modern pattern of term premiums in the South. Unfortunately, Homer and Sylla aren’t any help on this — it seems the only local bond markets in this period were in New England.

## The Interest Rate, the Interest Rate, and Secular Stagnation

In the previous post, I argued that the term “interest rate” is used to refer to two basically unrelated prices: The exchange rate between similar goods at different periods, and the yield on a credit-market instrument. Why does this distinction matter for secular stagnation?

Because if you think the “natural rate of interest,” in the sense of the credit-market rate that brings aggregate expenditure to a desired level in some real-world economic situation, should be the time-substitution rate that would exist in a model that somehow corresponds to that situation, when the two are in fact unrelated — well then, you are going to end up with a lot of irrelevant and misleading intuitions about what that rate should be.

In general, I do think the secular stagnation conversation is a real step forward. So it’s a bit frustrating, in this context, to see Krugman speculating about the “natural rate” in terms of a Samuelson-consumption loan model, without realizing that the “interest rate” in that model is the intertemporal substitution rate, and has nothing to do with the Wicksellian natural rate. This was the exact confusion introduced by Hayek, which Sraffa tore to pieces in his review, and which Keynes went to great efforts to avoid in General Theory. It would be one thing if Krugman said, “OK, in this case Hayek was right and Keynes was wrong.” But in fact, I am sure, he has no idea that he is just reinventing the anti-Keynesian position in the debates of 75 years ago.

The Wicksellian natural rate is the credit-market rate that, in current conditions, would bring aggregate expenditure to the level desired by whoever is setting monetary policy. Whether or not there is a level of expenditure that we can reliably associate with “full employment” or “potential output” is a question for another day. The important point for now is “in current conditions.” The level of interest-sensitive expenditure that will bring GDP to the level desired by policymakers depends on everything else that affects desired expenditure — the government fiscal position, the distribution of income, trade propensities — and, importantly, the current level of income itself. Once the positive feedback between income and expenditure has been allowed to take hold, it will take a larger change in the interest rate to return the economy to its former position than it would have taken to keep it there in the first place.

There’s no harm in the term “natural rate of interest” if you understand it to mean “the credit market interest rate that policymakers should target to get the economy to the state they think it should be in, from the state it in now.”And in fact, that is how working central bankers do understand it. But if you understand “natural rate” to refer to some fundamental parameter of the economy, you will end up hopelessly confused. It is nonsense to say that “We need more government spending because the natural rate is low,” or “we have high unemployment because the natural rate is low.” If G were bigger, or if unemployment weren’t high, there would be a different natural rate. But when you don’t distinguish between the credit-market rate and time-substitution rate, this confusion is unavoidable.

Keynes understood clearly that it makes no sense to speak of the “natural rate of interest” as a fundamental characteristic of an economy, independent of the current state of aggregate demand:

In my Treatise on Money I defined what purported to be a unique rate of interest, which I called the natural rate of interest — namely, the rate of interest which, in the terminology of my Treatise, preserved equality between the rate of saving (as there defined) and the rate of investment. I believed this to be a development and clarification of Wicksell’s “natural rate of interest”, which was, according to him, the rate which would preserve the stability if some, not quite clearly specified, price-level.

I had, however, overlooked the fact that in any given society there is, on this definition, a different natural rate of interest for each hypothetical level of employment. And, similarly, for every rate of interest there is a level of employment for which that rate is the “natural” rate, in the sense that the system will be in equilibrium with that rate of interest and that level of employment. Thus it was a mistake to speak of the natural rate of interest or to suggest that the above definition would yield a unique value for the rate of interest irrespective of the level of employment. I had not then understood that, in certain conditions, the system could be in equilibrium with less than full employment.

I am now no longer of the opinion that the concept of a “natural” rate of interest, which previously seemed to me a most promising idea, has anything very useful or significant to contribute to our analysis. It is merely the rate of interest which will preserve the status quo; and, in general, we have no predominant interest in the status quo as such.

EDIT: In response to Nick Edmonds in comments, I’ve tried to restate the argument of these posts in simpler and hopefully clearer terms:

Step 1 is to recognize that in a model like Samuelson’s, “interest rate” just means any contract that allows you to make a payment today and receive a flow of income in the future. It would be the exact same model, capturing the exact same features of the economy, if we wrote “profit rate” or “house price-to-rent ratio” instead of “interest rate.” Any valid intuition the model gives us, applies to ALL asset yields, not just to the the credit-instrument yields that we call “interest rates” in every day life.

Step 2 is to think about the other factors that enter into real-world asset yields, besides the intertemporal exchange rate Samuelson is interested in — risk, liquidity, carrying costs and depreciation, and expected capital gains. Since all real-world asset yields incorporate at least one of these factors, none correspond exactly to Samuelson’s intertemporal interest rate.

Step 3 is to realize that not only are credit-instrument yields not exactly the Samuelson “interest rate,” they aren’t even approximately it. The great majority of credit market transactions we see in real economies are not exchanges of present income for future income, but exchanges of two different claims on future income. So the intertemporal interest rate enters on both sides and cancels out.

At that point, we have established that the “interest rate” the monetary authority is targeting is not the “interest rate” Samuelson is writing about.

Step 4 is then to ask, what does it mean to say that some particular credit-market interest rate is the “natural” one? That is where the dependence on fiscal policy, income distribution, etc. come in. But those factors are not part of the argument for why the credit-market rate is not even approximately the intertemporal rate.

## The Interest Rate and the Interest Rate

We will return to secular stagnation. But we need to clear some ground first. What is an interest rate?

Imagine you are in a position to acquire a claim on a series of payments  in the future. Since an asset is just anything that promises a stream of payments in the future, we will say you are thinking of buying of an asset. What will you look at to make your decision?

First is the size of the payments you will receive, as a fraction of what you pay today. We will call that the yield of the asset, or y. Against that we have to set the risk that the payments may be different from expected or not occur at all; we will call the amount you reduce your expected yield to account for this risk r. If you have to make regular payments beyond the purchase of the asset to receive income from it (perhaps taxes, or the costs of operating the asset if it is a capital good) then we also must subtract these carrying costs c. In addition, the asset may lose value over time, in which case we have to subtract the depreciation rate d. (In the case of an asset that only lasts one period — a loan to be paid back in full the next period, say — d will be equal to one.) On the other hand, owning an asset can have benefits beyond the yield. In particular, an asset can be sold or used as collateral. If this is easy to do, ownership of the asset allows you to make payments now, without having to waiting for its yield in the future. We call the value of the asset for making unexpected payments its liquidity premium, l. The market value of long-lasting assets may also change over time; assuming resale is possible, these market value changes will produce a capital gain g (positive or negative), which must be added to the return. Finally, you may place a lower value on the payments from the asset simply because they take place in the future; this might be because your needs now are more urgent than you expect them to be then, or simply because you prefer income in the present to income in the future. Either way, we have to subtract this pure time-substitution rate i.

So the value of an asset costing one unit (of whatever numeraire) will be 1 + y – r – c – d + l + g – i.

(EDIT: On rereading, this could use some clarification:

Of course all the terms can take on different (expected) values in different time periods, so they are vectors, not scalars. But if we assume they are constant, and that the asset lasts forever (i.e. a perpetuity), then we should write its equilibrium value as: V = Y/i, where Y is the total return in units of the numeraire, i.e. Y = V(y – r – c + l + g) and i is the discount rate. Divide through both sides by V/i and we have i = y – r – c + l + g. We can now proceed as below.)

In equilibrium, you should be just indifferent between purchasing and not purchasing this asset, so we can write:

y – r – c – d + l + g – i = 0, or

(1) y = r + c + d – l – g + i

So far, there is nothing controversial.

In formal economics, from Bohm-Bawerk through Cassel, Fisher and Samuelson to today’s standard models, the practice is to simplify this relationship by assuming that we can safely ignore most of these terms. Risk, carrying costs and depreciation can be netted out of yields, capital gains must be zero on average, and liquidity is assumed not to matter or just ignored. So then we have:

(2) y = i

In these models, it doesn’t matter if we use the term “interest rate” to mean y or to mean i, since they are always the same.

This assumption is appropriate for a world where there is only one kind of asset — a risk-free contract that exchanges one good in the present for 1 + i goods in the future. There’s nothing wrong with exploring what the value of i would be in such a world under various assumptions.

The problem arises when we carry equation (2) over to the real world and apply it to the yield of some particular asset. On the one hand, the yield of every existing asset reflects some or all of the other terms. And on the other hand, every contract that involves payments in more than one period — which is to say, every asset — equally incorporates i. If we are looking for the “interest rate” of economic theory in the economic world we observe around us, we could just as well pick the rent-price ratio for houses, or the profit rate, or the deflation rate, or the ratio of the college wage premium to tuition costs. These are just the yields of a house, of a share of the capital stock, of cash and of a college degree respectively. All of these are a ratio of expected future payments to present cost, and should reflect i to exactly the same extent as the yield of a bond does. Yet in everyday language, it is the yield of the bond that we call “interest”, even though it has no closer connection to the interest rate of theory than any of these other yields do.

This point was first made, as far as I know, by Sraffa in his review of Hayek’s Prices and Production. It was developed by Keynes, and stated clearly in chapters 13 and 17 of the General Theory.

For Keynes, there is an additional problem. The price we observe as an “interest rate” in credit markets is not even the y of the bond, which would be i modified by risk, expected capital gains and liquidity. That is because bonds do not trade against baskets of goods. They trade against money. When we see a bond being sold with a particular yield, we are not observing the exchange rate between a basket of goods equivalent to the bond’s value today and baskets of goods equivalent to its yield in the future. We are observing the exchange rate between the bond today and a quantity of money today. That’s what actually gets exchanged. So in equilibrium the price of the bond is what equates the expected returns on the two assets:

(3) y_B – r_B + l_B + g_B – i = l_M – i

(Neither bonds nor money depreciate or have carrying costs, and money has no risk. If our numeraire is money then money also cannot experience capital gains. If our numeraire was a basket of goods instead, then -g would be expected inflation, which would appear on both sides and cancel out.)

What we see is that i appears on both sides, so it cancels out. The yield of the bond is given by:

(4) y_B  = r_B – g_B + (l_M – l_B)

The yield of the bond — the thing that in conventional usage we call the “interest rate” — depends on the risk of the bond, the expected price change of the bond, and the liquidity premium of money compared with the bond. Holding money today, and holding a bond today, are both means to enable you to make purchases in the future. So the intertemporal substitution rate i does not affect the bond yield.

(We might ask whether the arbitrage exists that would allow us to speak of a general rate of time-substitution i in real economies at all. But for present purposes we can ignore that question and focus on the fact that even if there is such a rate, it does not show up in the yields we normally call “interest rates”.)

This is the argument as Keynes makes it. It might seem decisive. But monetarists would reject it on the grounds that nobody in fact holds money as a store of value, so equation (3) does not apply. The bond-money market is not in equilibrium, because there is zero demand for money beyond that needed for current transactions at any price. (The corollary of this is the familiar monetarist claim that any change in the stock of  money must result in a proportionate change in the value of transactions, which at full employment means a proportionate rise in the price level.) From the other side, endogenous money theorists might assert that the money supply is infinitely elastic for any credit-market interest rate, so l_M is endogenous and equation (4) is underdetermined.

As criticisms of the specific form of Keynes’ argument, these are valid objections. But if we take a more realistic view of credit markets, we come to the same conclusion: the yield on a credit instrument (call this the “credit interest rate”) has no relationship to the intertemporal substitution rate of theory (call this the “intertemporal interest rate.”)

Suppose you are buying a house, which you will pay for by taking out a mortgage equal to the value of the house. For simplicity we will assume an amortizing mortgage, so you make the same payment each period. We can also assume the value of housing services you receive from the house will also be the same each period. (In reality it might rise or fall, but an expectation that the house will get better over time is obviously not required for the transaction to take place.) So if the purchase is worth making at all, then it will result in a positive income to you in every period. There is no intertemporal substitution on your side. From the bank’s point of view, extending the mortgage means simultaneously creating an asset — their loan to you — and a liability — the newly created deposit you use to pay for the house. If the loan is worth making at all, then the expected payments from the mortgage exceed the expected default losses and other costs in every period. And the deposits are newly created, so no one associated with the bank has to forego any other expenditure in the present. There is no intertemporal substitution on the bank’s side either.

(It is worth noting that there are no net lenders or net borrowers in this scenario. Both sides have added an asset and a liability of equal value. The language of net lenders and net borrowers is carried over from models with consumption loans at the intertemporal interest rate. It is not relevant to the credit interest rate.)

If these transactions are income-positive for all periods for both sides, why aren’t they carried to infinity? One reason is that the yields for the home purchaser fall as more homes are purchased. In general, you will not value the housing services from a second home, or the additional housing services of a home that costs twice as much, as much as you value the housing services of the home you are buying now. But this only tells us that for any given interest rate there is a volume of mortgages at which the market will clear. It doesn’t tell us which of those mortgage volume-interest rate pairs we will actually see.

The answer is on the liquidity side. Buying a house makes you less liquid — it means you have less flexibility if you decide you’d like to move elsewhere, or if you need to reduce your housing costs because of unexpected fall in income or rise in other expenses. You also have a higher debt-income ratio, which may make it harder for you to borrow in the future. The loan also makes the bank less liquid — since its asset-capital ratio is now higher, there are more states of the world in which a fall in income would require it to sell assets or issue new liabilities to meet its scheduled commitments, which might be costly or, in a crisis, impossible. So the volume of mortgages rises until the excess of housing service value over debt service costs make taking out a mortgage just worth the incremental illiquidity for the marginal household, and where the excess of mortgage yield over funding costs makes issuing a new mortgage just worth the incremental illiquidity for the marginal bank. (Incremental illiquidity in the interbank market may — or may not — mean that funding costs rise with the volume of loans, but this is not necessary to the argument.)

Monetary policy affects the volume of these kinds of transactions by operating on the l terms. Normally, it does so by changing the quantity of liquid assets available to the financial system (and perhaps directly to the nonfinancial private sector as well). In this way the central bank makes banks (and perhaps households and businesses) more or less willing to accept the incremental illiquidity of a new loan contract. Monetary policy has nothing to do with substitution between expenditure in the present period and expenditure in some future period. Rather, it affects the terms of substitution between more and less liquid claims on income in the same future period.

Note that changing the quantity of liquid assets is not the only way the central bank can affect the liquidity premium. Banking regulation, lender of last resort operations and bailouts also change the liquidity premium, by chaining the subjective costs of bank balance sheet expansion. An expansion of the reserves available to the banking system makes it cheaper for banks to acquire a cushion to protect themselves against the possibility of an unexpected fall in income. This will make them more willing to hold relatively illiquid assets like mortgages. But a belief that the Fed will take emergency action prevent a bank from failing in the event of an unexpected fall in income also increases its willingness to hold assets like mortgages. And it does so by the same channel — reducing the liquidity premium. In this sense, there is no difference in principle between monetary policy and the central bank’s role as bank supervisor and lender of last resort. This is easy to understand once you think of “the interest rate” as the price of liquidity, but impossible to see when you think of “the interest rate” as the price of time substitution.

It is not only the central bank that changes the liquidity premium. If mortgages become more liquid — for instance through the development of a regular market in securitized mortgages — that reduces the liquidity cost of mortgage lending, exactly as looser monetary policy would.

The irrelevance of the time-substitution rate i to the credit-market interest rate y_B becomes clear when you compare observed interest rates with other prices that also should incorporate i. Courtesy of commenter rsj at Worthwhile Canadian Initiative, here’s one example: the Baa bond rate vs. the land price-rent ratio for residential property.

Both of these series are the ratio of one year’s payment from an asset, to the present value of all future payments. So they have an equal claim to be the “interest rate” of theory. But as we can see, none of the variation in credit-market interest rates (y_B, in my terms) show up in the price-rent ratio. Since variation in the time-substituion rate i should affect both ratios equally, this implies that none of the variation in credit-market interest rates is driven by changes in the time-substitution interest rate. The two “interest rates” have nothing to do with each other.

(Continued here.)

EDIT: Doesn’t it seem strange that I first assert that mortgages do not incorporate the intertemporal interest rate, then use the house price-rent ratio as an example of a price that should incorporate that rate? One reason to do this is to test the counterfactual claim that interest rates do, after all, incorporate Samuelson’s interest rate i. If i were important in both series, they should move together; if they don’t, it might be important in one, or in neither.

But beyond that, I think housing purchases do have an important intertemporal component, in a way that loan contracts do not. That’s because (with certain important exceptions we are all aware of) houses are not normally purchased entirely on credit. A substantial fraction of the price is paid is upfront. In effect, most house purchases are two separate transactions bundled together: A credit transaction (for, say, 80 percent of the house value) in which both parties expect positive income in all periods, at the cost of less liquid balance sheets; and a conceptually separate cash transaction (for, say, 20 percent) in which the buyer foregoes present expenditure in return for a stream of housing services in the future. Because house purchases must clear both of these markets, they incorporate i in way that loans do not. But note, i enters into house prices only to the extent that the credit-market interest rate does not. The more important the credit-market interest rate is in a given housing purchase, the less important the intertemporal interest rate is.

This is true in general, I think. Credit markets are not a means of trading off the present against the future. They are a means of avoiding tradeoffs between the present and the future.