The Side Effects of Safe Asset Creation

We present an incomplete markets model to understand the costs and benefits of increasing government debt when an increased demand for safety pushes the natural rate of interest below zero. A higher demand for safe assets causes the ZLB to bind, increasing unemployment. Higher government debt satiates the demand for safe assets, raising the natural rate, and restoring full employment. However, this entails permanently lower investment, which reduces welfare, since our economy is dynamically efficient even when the natural rate is negative. Despite this, increasing debt until the ZLB no longer binds raises welfare when alternative instruments are unavailable. Higher inflation targets instead allow for negative real interest rates and achieve full employment without reducing investment.

The Case against the New "Secular Stagnation Hypothesis"

The new “secular stagnation hypothesis” developed by Lawrence H. Summers attempts to justify why the demand stimulus applied in the aftermath of the global financial crisis failed to revive growth in a satisfactory manner. Building on previous ideas of Keynes, Hansen, and Bernanke, Summers claims that excess savings together with feeble investment drove the natural rate of interest down to zero and advanced economies into stagnation. As the US monetary policy rate is not allowed to fall below the zero bound, Summers calls for “quantitative easing” and more expansionary fiscal policy to spur investment demand. This paper refutes Summers’s hypothesis by revealing its internal inconsistencies and presenting both theoretical arguments and empirical evidence on the long-term evolution of savings, investment, productivity, and capital stock. It also estimates the natural rate of interest following the approach of Salerno (2020), which is further refined based on Rothbard’s “pure interest rate” theory. The calculation shows that the natural interest rate did not drop to zero after the global financial crisis, but has actually remained consistently and significantly above the federal funds rate and the bank loan prime rate. This not only invalidates Summers’s central claim, but confirms once more the explanatory power of the Austrian business cycle theory in relation to the main trigger of the global financial crisis and its subsequent unfinished recovery.

Mind the (Convergence) Gap: Bond Predictability Strikes Back!

We show that the difference between the natural rate of interest and the current level of monetary policy stance, which we label Convergence Gap (CG), contains information that is valuable for bond predictability. Adding CG in forecasting regressions of bond excess returns significantly raises the R2, and restores countercyclical variation in bond risk premia that is otherwise missed by forward rates. Consistent with the argument that CG captures the effect of real imbalances on the path of rates, our factor has predictive ability for real bond excess returns. The importance of the gap remains robust out-of-sample and in countries other than the United States. Furthermore, its inclusion brings significant economic gains in the context of dynamic conditional asset allocation. This paper was accepted by Gustavo Manso, finance.

Concluding Remarks on the Negative Natural Rate of Interest

The Great Divergence: The period of production T is not rising anymore. The “waiting period” Z is rising over time with the rising standard of living and rising life expectancy, and this is the case worldwide. In the interest of full employment, the public debt periodD has to compensate for this divergence: T = Z − D. Using an extrapolation procedure that we have developed and the available empirical data, we calculate total private wealth in the OECD plus China region. Net public debt already accounts for nearly half of private wealth today. COVID-19 increases the optimal steady-statepublic debt period. Both our theory and our empirical findings are increasingly confirmed by the work of other economists: for example, by Lawrence Summers’secular stagnation thesis and by the study of Jordà, Schularick and others on the secular evolution of private wealth.

The Natural Rate of Interest and the Optimal Rate of Interest in the Steady State

The “natural rate of interest” is the hypothetical, risk-free real rate of interest that would obtain in a closed economy, if net public debt were zero. It is considerably less than the optimal steady-state rate of interest, which is equal to the system’s growth rate. This holds for a very general “meta-model.” The fundamental equation of capital theory holds on the optimal steady-state path: T = Z − D, where T is the overall economic period of production, Z is the representative private “waiting period” of consumers and D is the public debt ratio. Prosperity is at least 30% lower at the natural rate of interest than at the optimal rate.