Monetary Policy Surprises and the Brazilian Term Structure of Interest Rates

This paper examines the information content of COPOM decisions to change or to leave unchanged monetary policy by estimating the responses of the term structure to changes in the target for interest rates on COPOM meeting days. Within an event-study approach the evidence suggests that market participants anticipate, at least partially, monetary policy actions. Furthermore, it is found that the introduction of the floating exchange and inflation-targeting regime has had a dampening effect on interest rate surprises along the term structure.

On the Information Content of Oil Future Prices

This paper deals with the efficiency of the Brent Crude oil future contracts and tests whether futures can be used to predict realized oil spot prices. Evidence suggests that future prices up to three-months contracts on Brent Crude are unbiased predictors of future spot prices but the explanation power is not high (around 20%). Furthermore, using cointegration techniques the unbiasedness hypothesis for future prices as predictors of realized spot prices could not be rejected. When the sample is divided into sub-periods, the absence of bias in futures prices is rejected.

The Random Walk Hypothesis and the Behavior of Foreign Capital Portfolio Flows: the Brazilian Stock Market Case

In this paper the random walk hypothesis is tested for a set of daily Brazilian stock data given by the São Paulo Stock Exchange Index (IBOVESPA) in the period of 1986-1998. A rolling variance ratio test for different investment horizons was conducted, and it is concluded that prior to 1994 the random walk hypothesis is rejected but after that it cannot be rejected. Institutionally maturing markets, increasing liquidity and the openness of Brazilian markets for international capital can explain this increase of efficiency of the Brazilian stock market. An error-correction model is used to explain the relationship between the IBOVESPA and foreign portfolio inflows. Evidence suggests that the release of foreign capital control is one of the main determinants of increased efficiency in the Brazilian equity market.

Decentralized Portfolio Management

Within a mean-variance model we analyze the problem of decentralized portfolio management. We find the solution for the optimal portfolio allocation for a head trader operating in n different markets, which is called the optimal centralized portfolio. However, as there are many traders specialized in different markets, the solution to the problem of optimal decentralized allocation should be different from the centralized case. In this paper we derive conditions for the solutions to be equivalent. We use multivariate normal returns and a negative exponential function to solve the problem analytically. We generate the equivalence of solutions by assuming that different traders face different interest rates for borrowing and lending. This interest rate is dependent on the ratio of the degrees of risk aversion of the trader and the head trader, on the excess return, and on the correlation between asset returns.

Delegated Portfolio Management

In this paper, we examine optimal portfolio decisions within a decentralized framework. There are many portfolio managers choosing optimal portfolio weights in a mean-variance framework and taking decisions in a decentralized way. However, the overall portfolio may not be efficient, as the portfolio managers do not take into account the overall covariance matrix. We show that the initial endowment that portfolio managers can use within the firm in order to manage their portfolios can be used as a control variable by the top administration and redistributed within the firm in order to achieve overall efficiency.

On the information content of oil future prices

This paper deals with the efficiency of the Brent Crude oil future contracts and tests whether futures can be used to predict realized oil spot prices. Evidence suggests that future prices up to three-months contracts on Brent Crude are unbiased predictors of future spot prices but the explanation power is not high (around 20%). Furthermore, using cointegration techniques the unbiasedness hypothesis for future prices as predictors of realized spot prices could not be rejected. When the sample is divided into sub-periods, the absence of bias in futures prices is rejected

The Effects of the Brazilian ADRs Program on Domestic Market Efficiency

This paper examines the impact on Brazilian stocks following American Depositary Receipts (ADRs) listing in the U.S. stock markets. Evidence suggests that a systematic change has taken place in the post-listing period as the multivariate variance ratio statistics have significantly decreased if compared to the pre-listing period, which indicates a move toward a more efficient domestic stock market. This empirical evidence is robust to the use of dollar and local currency-denominated returns. These results add to the literature that finds evidence on changes in domestic volatility and abnormal returns around listing dates.

Is it Worth Tracking Dollar/Real Implied Volatility?

In this paper we examine the relation between dollar-real exchange rate volatility implied in option prices and subsequent realized volatility, in the period of February 1999 to June 2000. Our results are in line with recent literature, suggesting that the implied volatility obtained from a simple option-pricing model, although an upward-biased estimator of future volatility does provide information about volatility over the remaining life of the option, which is not present in past returns. Results are robust to the choice of two alternative time series models to explore information embedded in returns, a fixed volatility and a GARCH (1,1) model, even allowing for in-sample forecasts by the GARCH (1,1) model. Results are also robust to the choice of measuring realized volatility in two alternative ways.

Exchange Rate Dynamics and the Relationship between the Random Walk Hypothesis and Official Interventions

This paper examines the empirical evidence that official interventions are associated with periods of high predictability in exchange rate markets. We employ a block bootstrap methodology to build critical values for the Variance Ratio statistics and test for predictability within moving windows of fixed length sizes for major developed countries currencies. Empirical results suggest that interventions are indeed associated to periods of increase in predictability and that time varying risk premium may, at least partially, explain such results.

Testing the Expectations Hypothesis in the Brazilian Term Structure of Interest Rates

In this paper the Expectations Hypothesis (EH) is tested using cointegration techniques, for maturities ranging from 1-month to 12-months, for the Brazilian market. We found evidence suggesting that for the period 1995-2001, the cointegration implication generally seems to hold. We also found strong evidence supporting causality from short to long rates and also in the opposite direction. Empirical evidence supports the expectations theory of the term structure of interest rates. However, when using multivariate cointegration tests we reject the unbiasedness hypothesis implied in the pure EH.