What’s at stake: Former Chairman of the Federal Reserve and new blogger Ben Bernanke has generated many discussions this week by challenging the secular stagnation idea. Bernanke argues, in particular, that the stagnationists have failed to properly take into account how capital flows can mitigate or even eliminate the problems generated by secular stagnation at home.









What’s at stake: Former Chairman of the Federal Reserve and new blogger Ben Bernanke has generated many discussions this week by challenging the secular stagnation idea. Bernanke argues, in particular, that the stagnationists have failed to properly take into account how capital flows can mitigate or even eliminate the problems generated by secular stagnation at home.

The global secular stagnation hypothesis

Ben Bernanke writes that secular stagnation requires that the returns to capital investment be permanently low everywhere, not just in the home economy. All else equal, the availability of profitable capital investments anywhere in the world should help defeat secular stagnation at home. The foreign exchange value of the dollar is one channel through which this could work: If US households and firms invest abroad, the resulting outflows of financial capital would be expected to weaken the dollar, which in turn would promote US exports. Increased exports would raise production and employment at home, helping the economy reach full employment.

Ben Bernanke writes that many of the factors cited by secular stagnationists (such as slowing population growth) may be less relevant for other countries. Currently, many major economies are in cyclically weak positions, so that foreign investment opportunities for US households and firms are limited. But unless the whole world is in the grip of secular stagnation, at some point attractive investment opportunities abroad will reappear. If that’s so, then any tendency to secular stagnation in the US alone should be mitigated or eliminated by foreign investment and trade.

Paul Krugman writes that international capital mobility makes a liquidity trap in just one country less likely, but it by no means rules that possibility out. You might think that you can’t have a liquidity trap in just one country, as long as capital is mobile. As long as there are positive-return investments abroad, capital will flow out. This will drive down the value of the home currency, increasing net exports, and raising the Wicksellian natural rate. But this isn’t right if the weakness in demand is perceived as temporary. For in that case the weakness of the home currency will also be seen as temporary: the further it falls, the faster investors will expect it to rise back to a “normal” level in the future. And this expected appreciation back toward normality will equalize expected returns after a decline in the home currency that is well short of being enough to raise the natural rate of interest all the way to its level abroad.

Tyler Cowen writes that it’s the wrong comparison of interest rates and the wrong metric of expected currency appreciation. Rather than looking at real interest rate differentials, take the market’s implied prediction for the euro to be the forward-futures exchange rates. These futures rates match the differences in nominal rates on each currency across the relevant time horizons. Those equilibrium relationships hold true with or without secular stagnation, whether in one country or in “n” countries, and from those relationships you cannot derive the claim that expected currency movements offset cross-border differences in real rates of return. The best way to speak of the non-ss countries, for international economics, is that their corporate sectors offer nominal expected rates of return which are relatively high, compared to their nominal government bond rates. Once you see this as the correct terminology, it is obvious that capital still will flow outwards to the non-ss countries, even with expected exchange rate movements.

Negative interest rates in theory and practice

Ben Bernanke writes that if the real interest rate were expected to be negative indefinitely, almost any investment is profitable. For example, at a negative (or even zero) interest rate, it would pay to level the Rocky Mountains to save even the small amount of fuel expended by trains and cars that currently must climb steep grades. It’s therefore questionable that the economy’s equilibrium real rate can really be negative for an extended period. Bernanke concedes that there are some counterarguments to this point; for example, because of credit risk or uncertainty, firms and households may have to pay positive interest rates to borrow even if the real return to safe assets is negative. Also, Eggertson and Mehrotra (2014) offers a model for how credit constraints can lead to persistent negative returns.

Larry Summers writes that negative real rates are a phenomenon that we observe in practice if not always in theory. The essence of secular stagnation is a chronic excess of saving over investment. Ben Bernanke grudgingly acknowledges that there are many theoretical mechanisms that could give rise to zero rates. To name a few: credit markets do not work perfectly, property rights are not secure over infinite horizons, property taxes that are explicit or implicit, liquidity service yields on debt, and investors with finite horizons.

Secular stagnation vs. global savings glut: the policy implications

Matt O’Brien writes that even though secular stagnation and the global saving glut are distinct economic stories, it’s easy to confuse them since they look the same. Output is below potential and interest rates are low in both, which is just another way of saying that people want to save more than they want to invest. Secular stagnation says it’s because there isn’t enough demand for investment, while the global saving glut says, yes, it’s because there’s too much supply of savings. Now why does it matter which it is? Well, as Bernanke points out, different problems have different solutions. Secular stagnation means the economy is broken and the government needs to fix it by giving us more inflation and more infrastructure spending. But the global saving glut means the economy wouldn’t need any fixing if governments would stop breaking it by manipulating their currencies down to run bigger and bigger surpluses and amass bigger and bigger piles of dollars.

Ben Bernanke writes that there is some similarity between the global saving glut and secular stagnation ideas. An important difference, however, is that stagnationists tend to attribute weakness in capital investment to fundamental factors, like slow population growth, the low capital needs of many new industries, and the declining relative price of capital. In contrast, with a few exceptions, the savings glut hypothesis attributes the excess of desired saving over desired investment to government policy decisions, such as the concerted efforts of the Asian EMEs to reduce borrowing and build international reserves after the Asian financial crisis of the late 1990s.

Ben Bernanke writes that of course, there are barriers to the international flow of capital or goods that may prevent profitable foreign investments from being made. But if that’s so, then we should include the lowering or elimination of those barriers as a potentially useful antidote to secular stagnation in the US. Matt O’Brien writes that we used to have a global saving glut caused by other country’s policy decisions, but now we have a global saving glut caused by other country’s secular stagnation. If that’s right, then it’s not going to be enough to browbeat countries that aren’t spending a lot into spending more.

Ryan Avent writes secular stagnation creates a dilemma. The ageing societies of the rich world want rapid income growth and low inflation and a decent return on safe investments and limited redistribution and low levels of immigration. Well you can’t have all of that. The rich world could address the imbalance within its economies while simultaneously addressing the geographic imbalance by allowing much more immigration. Investing in people in developing countries in hard and risky. But if those people wanted to come to America and were allowed to, then lots of things change. Investing in those people would not then require that money be sent abroad, to a different financial system in a different currency overseen by a different government. If the savings are in rich countries and the most productive investments are in poor ones, then the savings can move or the investments can move.