The term structure of S&P 100 model-free volatilities

We develop an improved method to obtain the model-free volatility more accurately despite the limitations of a finite number of options and large strike price intervals. Our method computes the model-free volatility from European-style S&P 100 index options over a horizon of up to 450 days, the first time that this has been attempted, as far as we are aware. With the estimated daily term structure over the long horizon, we find that (i) changes in model-free volatilities are asymmetrically more positively impacted by a decrease in the index level than negatively impacted by an increase in the index level; (ii) the negative relationship between the daily change in model-free volatility and the daily change in index level is stronger in the near term than in the far term; and (iii) the slope of the term structure is positively associated with the index level, having a tendency to display a negative slope during bear markets and a positive slope during bull markets. These significant results have important implications for pricing and hedging index derivatives and portfolios.     

What is the impact of wealth shocks on asset allocation?

I test the assumption of constant relative risk aversion using U.S. macroeconomic data and analyse the role of wealth shocks in generating transitory changes in asset portfolio composition. I show that the risky asset share exhibits cyclical behavior and it is significantly (and positively) affected by unexpected variation in wealth. Therefore, the empirical evidence suggests that risk aversion is counter-cyclical. I also find that the portfolio share of housing wealth falls when the agent is faced with a positive wealth shock, i.e. housing is a hedge against unfavorable wealth fluctuations. Finally, considering a variety of wealth definitions, the results show that: (i) wealth effects are stronger for direct holdings of risky assets than for indirect holdings, which highlights that investors do not typically trade some assets such as pension or mutual funds; (ii) although significant, wealth effects on asset allocation are mainly temporary as agents quickly rebalance the asset portfolio composition (i.e. there is weak evidence of inertia or slow adjustment in asset allocation); and (iii) changes in expected returns partially explain the variation in risky asset allocation.     

Portfolio allocation and the investment horizon: a multiscaling approach

A new approach is proposed for analysing portfolio allocation over various time scales. This new approach is based on wavelet analysis, which decomposes a given time series on a scale-by-scale basis. Empirical results indicate that, as the investment horizon lengthens, a greater weighting should be allocated to stocks. An explanation for this result is that the mean-reverting property of stock returns causes investors to perceive that stocks are less risky than bonds and T-bills at longer time scales compared with shorter time scales. When we include the effect of risk aversion, it is found that the higher the risk aversion, the less the Sharpe ratio, indicating that a more conservative investor prefers a smoother consumption stream.     

An empirical re-examination of the dividend–investment relation

Modigliani and Miller show that, in perfect capital markets, the optimal investment decisions of a firm are not affected by how these investments are financed. Miller and Modigliani further imply that, under the assumption of perfect capital markets, a firm's investment decisions are not affected by its dividend decisions, although dividend decisions may or may not be influenced by investment decisions. Fama and Miller label this result the separation principle. Most recent studies of the separation principle that take into account the existence of market imperfections report sharply contradictory results. This paper tests for linear and nonlinear causality between dividends and investments using both firm-specific and aggregate data for a sample of 417 firms over the 1962 to 2004 period. In general, linear causality tests support the separation principle, whereas nonlinear causality test results contradict the separation principle by revealing strong bi-directional linkages between dividends and investments.     

投资者保护与收益质量:国际比较研究

本文主要利用实证和国际比较的方法研究了外部投资者保护对上市公司收益质量的影响,以及我国投资者保护和收益质量在国际上所处的水平,并对如何通过提高投资者保护水平以提高上市公司收益质量提出了建议.     

When does low interconnectivity cause systemic risk?

We analysed a systemic liquidity crisis by using a unique money market data-set in which the coded identity of the counterparties of each trade is known. Contrary to recent findings, we did not observe a positive relationship between interconnectivity and systemic risk. We have concluded that our conflicting findings can be related to the degree of market concentration on the borrowing side of the funding market. High level of concentration in the borrowing side led to lower interconnectivity but higher systemic risk prior to the crisis. We conclude that measures of market heterogeneity should be used to generalize the relationship between systemic risk and interconnectivity.