Long-range correlations and nonstationarity in the Brazilian stock market

We report an empirical study of the Ibovespa index of the Sao Paulo Stock Exchange in which we detect the existence of long-range correlations. To analyze our data we introduce a rescaled variant of the usual Detrended Fluctuation Analysis that allows us to obtain the Hurst exponent through a one-parameter fitting. We also compute a time-dependent Hurst exponent H(t) using three-year moving time windows. In particular, we find that before the launch of the Collor Plan in 1990 the curve H(t) remains, in general, well above 1/2, while afterwards it stays close to 1/2. We thus argue that the structural reforms set off by the Collor Plan has lead to a more efficient stock market in Brazil. We also suggest that the time dependence of the Ibovespa Hurst exponent could be described in terms of a multifractional Brownian motion.Comment: 19 pages with 11 figures, submitted to Physica

Bayesian analysis of FIAPARCH model: an application to São Paulo stock market

In this paper, we develop a Bayesian analysis of a FIAPARCH(p,d,q) model for parameter estimation and conditional variance prediction. In order to study the inference problem we use the Metropolis-Hastings algorithm.This methodology is illustrated in a simulation study and it is applied to a set of observations concerning the returns of IBOVESPA value

Are Price Limits on Futures Markets That Cool? Evidence from the Brazilian Mercantile and Futures Exchange

This paper investigates the impact of price limits on the Brazilian futures markets using high frequency data. The aim is to identify whether there is a cool-off or a magnet effect. For that purpose, we examine a tick-by-tick data set that includes all contracts on the S�o Paulo stock index futures traded on the Brazilian Mercantile and Futures Exchange from January 1997 to December 1999. The results indicate that the conditional mean features a floor cool-off effect, whereas the conditional variance significantly increases as the price approaches the upper limit. We then build a trading strategy that accounts for the cool-off effect in the conditional mean so as to demonstrate that the latter has not only statistical, but also economic significance. The in-sample Sharpe ratio indeed is way superior to the buy-and-hold benchmarks we consider, whereas out-of-sample results evince similar performances.Cool-off effect, Futures markets, Magnet effect, Price limits, Transactions data

Interdependence and Contagion: an Analysis of Information Transmission in Latin America's Stock Markets

This paper brings evidences about the hypotheses of financial crisis contagion over Latin American stock markets in the 90's using a multivariate GARCH model. Beside the traditional volatility structure, we added a leverage term like GJR framework in order to avoid problems due to the use of conditional correlation as a measure of relationship between stock markets. The results show the existence of contagion only during the Asian (1997) and the Russian (1998) crises. The consequences of the Brazilian crisis (1999) can be identified as a result of interdependence among Latin American markets, while the crises of Mexico (1994) and Argentina (2001) show a specific mechanism of propagation. This result raises questions about the "contagion" and "interdependence" concepts' adequacy for the analysis of information transmission among stock markets.

Portfolio selection models: comparative analysis and applications to the Brazilian stock market

This paper presents a comparison of three portfolio selection models, Mean-Variance (MV), Mean Absolute Deviation (MAD), and Minimax, as applied to the Brazilian Stock Market (BOVESPA). For this comparison, we used BOVESPA data from three different 12 month time periods: 1999 to 2000, 2001, and 2002 to 2003. Each model generated three optimal portfolios for each period, with performance determined by monthly returns over the period. In general, the accumulated returns from the Minimax modeled portfolios were superior to the BOVESPA’s principal index, the IBOVESPA. The MV model was the least efficient for portfolio selection.Portfolio selection, Stock market, Brazil, Financial Economics,