Christelle Lecourt

Testing for jumps in conditionally Gaussian ARMA-GARCH models, a robust approach

Financial asset prices occasionally exhibit large changes. To deal with their occurrence, observed return series are assumed to consist of a conditionally Gaussian ARMA-GARCH type model contaminated by an additive jump component. In this framework, a new test for additive jumps is proposed. The test is based on standardized returns, where the first two conditional moments of the non-contaminated observations are estimated in a robust way. Simulation results indicate that the test has very good finite sample properties, i.e. correct size and high proportion of correct jump detection. The test is applied to daily returns and detects less than 1% of jumps for three exchange rates and between 1% and 3% of jumps for about 50 large capitalization stock returns from the NYSE. Once jumps have been filtered out, all series are found to be conditionally Gaussian. It is also found that simple GARCH-type models estimated using filtered returns deliver more accurate out-of sample forecasts of the conditional variance than GARCH and Generalized Autoregressive Score (GAS) models estimated from raw data.

Does Transparency in Central Bank Intervention Policy Bring Noise to the FX Market? The Case of the Bank of Japan

This paper empirically investigates the induced effect of a more and less transparent central bank intervention (CBI) policy on rumors that can emerge. Using the case of Japan, we estimate a dynamic-probit model that explains the main determinants of false reports (i.e. falsely reported interventions) and anticipative rumors (i.e. rumors about future interventions) with reference to the intervention strategy adopted by the central bank for actual and oral interventions, and the uncertainty climate of the market captured by two volatility measures. Our results suggest that the induced effect of a transparent CBI policy on market rumors critically depends on the type of speeches made by officials.

The intra-day impact of communication on euro-dollar volatility and jumps

In this paper, we examine the intra-day effects of verbal statements and comments on the FX market uncertainty using two measures: continuous volatility and discontinuous jumps. Focusing on the euro-dollar exchange rate, we provide empirical evidence of how these two sources of uncertainty matter in measuring the short-term reaction of exchange rates to communication events. Talks significantly trigger large jumps or extreme events for approximately an hour after the news release. Continuous volatility starts reacting prior to the news, intensifies around the release time and stays at high levels for several hours. Our results suggest that monetary authorities generally tend to communicate with markets on days when uncertainty is relatively severe, and higher than normal. Disentangling the US and Euro area statements, we also find that abnormal levels of volatility are mostly driven by the communication of the Euro area officials rather than US authorities.

How Transparent is the Intervention Exchange Rate Policy of the Bank of Japan

In this paper a new approach relying on news wire reports is used to capture all the transparency elements in the exchange rate intervention policy of the Bank of Japan during the period 1991-2004. As suggested by Enoch (1998), we distinguish three types of transparency: ex ante transparency, represented by oral interventions suggesting a potential future intervention; real time transparency proxied by news reports of interventions; and ex post transparency where the central bank confirms or explains its interventions after the event. We also consider the effect of a more or less transparent intervention policy on the markets perceptions and the rumours that it can bring out. We find that the transparency of the Bank of Japans intervention policy varied greatly over time, with three distinct periods. We also find that less transparency in the exchange rate intervention policy induces more false or uncertain reports of interventions, but too much transparency can generate anticipative rumours.

Do jumps mislead the FX market

This paper investigates the link between jumps in the exchange rate process and rumours of central bank interventions. Using the case of Japan, we analyse specifically whether jumps trigger false reports of intervention (i.e. an intervention is reported when it did not occur). Intraday jumps are extracted using a non-parametric technique recently proposed by Lee and Mykland in 2008 and by Andersen et al. in 2007, and later modified by Boudt et al. in 2011. Rumours are identified by using a unique database of Reuters and Dow Jones newswires. Our results suggest that a significant number of jumps on the YEN/USD have been falsely interpreted by the market as being the result of a central bank intervention. The paper has policy implications in terms of central bank interventions. We show that in times where the central bank is known to intervene, some investors may attach a lot of weight to central bank interventions as a source of exchange rate movement, leading to a false ‘intervention explanation’ for observed jumps.