Portfolio Selection with Two-Stage Preferences

We propose a model of portfolio selection under ambiguity, based on a two-stage valuation procedure which disentangles ambiguity and ambiguity aversion. The model does not imply 'extreme pessimism' from the part of the investor, as multiple priors models do. Furthermore, its analytical tractability allows to study complex problems thus far not analyzed, such as joint uncertainty about means and variances of returns.ambiguity, portfolio selection, parameter uncertainty.

Macro-finance VARs and bond risk premia: a caveat

Around the turn of the Twentieth century, US and euro area long-term bond yields experienced a remarkable decline and remained at historically low levels even in the face of rising short-term rates (the so called "conundrum"). This unusual phenomenon has been analyzed by many researchers through the lens of macro-finance VARs and no-arbitrage term structure models. A commonly found result is that the decline in long-term rates was primarily driven by an unprecedented reduction in risk premia. I show that such result might be an artefact of the class of models employed to study the phenomenon. I propose an alternative model which suggests that, although risk premia played an important role in reducing bond yields, other two equally important forces were at play, i.e. a decline in the real natural rate of interest and a structural reduction in inflation expectations. I conclude that, after accounting for permanent shifts in the expectations about the future path of short-term rates, the dynamics of risk premia observed after the turn of the century have not been unusual if considered from an historical perspective.Bond yields, forward premia, macro-finance models

The riskiness of corporate bonds

When the riskiness of an asset increases, then, arguably, some risk-averse agents that were previously willing to hold on to the asset are no longer willing to do so. Aumann and Serrano (2008) have recently proposed an index of riskiness that helps to make this intuition rigorous. We use their index to analyze the riskiness of corporate bonds and how this can change over time and across rating classes and how it compares to the riskiness of other financial instruments. We find statistically significant evidence that a number of financial and macroeconomic variables can predict time-variation in the riskiness of corporate bonds, including in ways one might not expect. For example, a higher yield-to-maturity lowers riskiness by reducing the frequency and the magnitude of negative holding-period returns.riskiness, corporate bonds, predictability

Structural change and the bond yield conundrum

In recent years, US and euro area long-term bond yields experienced a remarkable decline and remained at historically low levels even in the face of rising short-term rates. This unusual phenomenon (the so called ”conundrum”) has been the subject of numerous debates and extensive research. The most commonly held opinion is that it was primarily driven by an unprecedented reduction in risk premia. I partly counter this view by showing that, although risk premia played an important role in the ”conundrum” episode, other two equally important forces were at play, i.e. a decline in the real natural rate of interest and a structural reduction in inflation expectations. I use a small-scale macroeconometric model to provide evidence that structural changes in the economy lowered expectations about the future path of short-term policy rates and that, although risk premia did diminish, their current level is not unusual if considered from an historical perspective.

Canonical term-structure models with observable factors and the dynamics of bond risk premiums

We study the dynamics of risk premiums on the German bond market, employing no-arbitrage term-structure models with both observable and unobservable state variables, recently popularized by Ang and Piazzesi (2003). We conduct a specification analisys based on a new canonical representation for this class of models. We find that risk premiums display a considerable variability over time, are strongly counter-cyclical and bear no significant relation to inflation.term structure models, yield curve, risk premium

Bond risk premia, macroeconomic fundamentals and the exchange rate

We introduce a two-country no-arbitrage term-structure model to analyse the joint dynamics of bond yields, macroeconomic variables, and the exchange rate. The model allows to understand how exogenous shocks to the exchange rate affect the yield curves, how bond yields co-move in different countries, and how the exchange rate is influenced by the interactions between macroeconomic variables and time-varying bond risk premia. Estimating the model with US and German data, we obtain an excellent fit of the yield curves and we are able to account for up to 75 per cent of the variability of the exchange rate. We find that time-varying risk premia play a non-negligible role in exchange rate fluctuations due to the fact that a currency tends to appreciate when risk premia on long-term bonds denominated in that currency rise. A number of other novel empirical findings emerge.exchange rate, term structure, UIP

The realized equity premium has been higher than expected: further evidence.

We propose a new approach to the study of stock returns. We develop a simple model to show that, in the long run, the average rate of return on the market portfolio equals the average growth rate of income plus an average payout rate measuring the quantity of financial resources distributed or absorbed by quoted firms. We exploit this framework to calculate expected returns using U.S. stock market data.equity premium puzzle realized risk finance expected

Bayesian analysis of coefficient instability in dynamic regressions

This paper proposes a Bayesian regression model with time-varying coefficients (TVC) that makes it possible to estimate jointly the degree of instability and the time-path of regression coefficients. Thanks to its computational tractability, the model proves suitable to perform the first (to our knowledge) Monte Carlo study of the finite-sample properties of a TVC model. Under several specifications of the data generating process, the proposed model’s estimation precision and forecasting accuracy compare favourably with those of other methods commonly used to deal with parameter instability. Furthermore, the TVC model leads to small losses of efficiency under the null of stability and it is robust to mis-specification, providing a satisfactory performance also when regression coefficients experience discrete structural breaks. As a demonstrative application, we use our TVC model to estimate the exposures of S&P 500 stocks to market-wide risk factors: we find that a vast majority of stocks have time-varying risk exposures and that the TVC model helps to forecast these exposures more accurately.time-varying regression, coefficient instability

A specification analysis of discrete-time no-arbitrage term structure models with observable and unobservable factors

We derive a canonical representation for the no-arbitrage discrete-time term structure models with both observable and unobservable state variables, popularized by Ang and Piazzesi (2003). We conduct a specification analysis based on this canonical representation. We show that some of the restrictions commonly imposed in the literature, most notably that of independence between observable and unobservable variables, are not necessary for identification and are rejected by formal statistical tests. Furthermore, we show that there are important differences between the estimated risk premia, impulse response functions and variance decomposition of unrestricted models, parametrized according to our canonical representation, and those of models with overidentifying restrictions.Term structure; canonical models

Portfolio Selection with Monotone Mean-Variance Preferences.

We propose a portfolio selection model based on a class of preferences that coincide with mean-variance preferences on their domain of monotonicity, but differ where mean-variance preferences fail to be monotone.