Vivian Z. Yue

Global Yield Curve Dynamics and Interactions: A Dynamic Nelson-Siegel Approach

The popular Nelson-Siegel (1987) yield curve is routinely fit to cross sections of intra-country bond yields, and Diebold and Li (2006) have recently proposed a dynamized version. In this paper we extend Diebold-Li to a global context, modeling a potentially large set of country yield curves in a framework that allows for both global and country-specific factors. In an empirical analysis of term structures of government bond yields for the Germany, Japan, the U.K. and the U.S., we find that global yield factors do indeed exist and are economically important, generally explaining significant fractions of country yield curve dynamics, with interesting differences across countries.

A Solution to the Default Risk-Business Cycle Disconnect

Models of business cycles in emerging economies explain the negative correlation between country spreads and output by modeling default risk as an exogenous interest rate on working capital. Models of strategic default explain the cyclical properties of sovereign spreads by assuming an exogenous output cost of default with special features, and they underestimate debt-output ratios by a wide margin. This paper proposes a solution to this default risk-business cycle disconnect based on a model of sovereign default with endogenous output dynamics. The model replicates observed V-shaped output dynamics around default episodes, countercyclical sovereign spreads, and high debt ratios, and it also matches the variability of consumption and the countercyclical fluctuations of net exports. Three features of the model are key for these results: (1) working capital loans pay for imported inputs; (2) imported inputs support more efficient factor allocations than when these inputs are produced internally; and (3) default on the foreign obligations of firms and the government occurs simultaneously.

Exchange Rate Policy and Sovereign Bond Spreads in Developing Countries

This paper empirically analyzes how exchange rate policy affects the issuance and pricing of international bonds for developing countries. We find that countries with less flexible exchange rate regimes pay higher sovereign bond spreads and are less likely to issue bonds. Quantitatively, changing a free-floating regime to a fixed regime decreases the likelihood of bond issuance by 4.6% and increases the bond spread by 1.3% on average. Furthermore, countries with real exchange rate overvaluation have higher bond spreads and higher bond issuance probabilities. Moreover, such positive effects of real exchange rate overvaluation tend to be magnified for countries with fixed exchange rate regimes. Our results suggest that choosing a less flexible exchange rate regime in general leads to higher borrowing costs for developing countries, especially when their currencies are overvalued.

Export dynamics in large devaluations

We study the source and consequences of sluggish export dynamics in emerging markets following large devaluations. We document two main features of exports that are puzzling for standard trade models. First, given the change in relative prices, exports tend to grow gradually following a devaluation. Second, high interest rates tend to suppress exports. To address these features of export dynamics, we embed a model of endogenous export participation due to sunk and per period export costs into an otherwise standard small open economy. In response to shocks to productivity, the interest rate, and the discount factor, we find the model can capture the salient features of export dynamics documented. At the aggregate level, the features giving rise to sluggish exports lead to more gradual net export reversals, sharper contractions and recoveries in output, and endogenous stagnation in labor productivity.

A Model of the Twin Ds: Optimal Default and Devaluation

This paper characterizes jointly optimal default and exchange-rate policy in a small open economy with limited enforcement of debt contracts and downward nominal wage rigidity. Under optimal policy, default occurs during contractions and is accompanied by large devaluations. The latter inflate away real wages thereby avoiding massive unemployment. Thus, the Twin Ds phenomenon emerges endogenously as the optimal outcome. By contrast, under fixed exchange rates, optimal default takes place in the context of large involuntary unemployment. Fixed-exchange-rate economies are shown to have stronger default incentives and therefore support less external debt than economies with optimally floating rates.

A General Equilibrium Model of Sovereign Default and Business Cycles

Emerging markets business cycle models treat default risk as part of an exogenous interest rate on working capital, while sovereign default models treat income fluctuations as an exogenous endowment process with ad-hoc default costs. We propose instead a general equilibrium model of both sovereign default and business cycles. In the model, some imported inputs require working capital financing; default triggers an efficiency loss as these inputs are replaced by imperfect substitutes; and default on public and private obligations occurs simultaneously. The model explains several features of cyclical dynamics around defaults, countercyclical spreads, high debt ratios, and key business cycle moments.

Liquidity Backstops and Dynamic Debt Runs

Liquidity backstops have important implications for financial stability. In this paper, we provide a microfoundation for the important role of liquidity backstops in mitigating runs (or, conversely, the role of the lack of liquidity backstops in exacerbating runs) based on a dynamic model of debt runs. We focus on the municipal bond markets for variable rate demand obligations (VRDOs) and auction rate securities (ARS). The different experiences in these markets during the recent financial crisis of 2007–09 provide a natural experiment to identify the value of a liquidity backstop in mitigating runs. Through structural estimation of the model, we show that the value of a liquidity backstop is about 14.5 basis points per annum. The results in this paper shed light on one central difference between shadow banks and traditional banks in terms of their differential access to public liquidity backstops.