Faruk Selcuk

Scaling properties of foreign exchange volatility

In this paper, we investigate the scaling properties of foreign exchange volatility. Our methodology is based on a wavelet multi-scaling approach which decomposes the variance of a time series and the covariance between two time series on a scale by scale basis through the application of a discrete wavelet transformation. It is shown that foreign exchange rate volatilities follow different scaling laws at different horizons. Particularly, there is a smaller degree of persistence in intra-day volatility as compared to volatility at one day and higher scales. Therefore, a common practice in the risk management industry to convert risk measures calculated at shorter horizons into longer horizons through a global scaling parameter may not be appropriate. This paper also demonstrates that correlation between the foreign exchange volatilities is the lowest at the intra-day scales but exhibits a gradual increase up to a daily scale. The correlation coefficient stabilizes at scales one day and higher. Therefore, the benefit of currency diversification is the greatest at the intra-day scales and diminishes gradually at higher scales (lower frequencies). The wavelet cross-correlation analysis also indicates that the association between two volatilities is stronger at lower frequencies.

Differentiating intraday seasonalities through wavelet multi-scaling

It is well documented that strong intraday seasonalities may induce distortions in the estimation of volatility models. These seasonalities are also the dominant source for the underlying misspecifications of the various volatility models. Therefore, an obvious route is to filter out the underlying intraday seasonalities from the data. In this paper, we propose a simple method for intraday seasonality extraction that is free of model selection parameters which may affect other intraday seasonality filtering methods. Our methodology is based on a wavelet multi-scaling approach which decomposes the data into its low- and high-frequency components through the application of a non-decimated discrete wavelet transform. It is simple to calculate, does not depend on a particular model selection criterion or model-specific parameter choices. The proposed filtering method is translation invariant, has the ability to decompose an arbitrary length series without boundary adjustments, is associated with a zero-phase filter and is circular. Being circular helps to preserve the entire sample unlike other two-sided filters where data loss occurs from the beginning and the end of the studied sample.

Currency substitution in Turkey

Although currency substitution is a widely observed phenomenon in both developed and developing counries, most of the studies on currency substitutioin in small open economies have focused on high inflatin South American countries. This paper extends the previous analysis to a newly industrializing, high-inflation economy, namely Turkey. A vector autoregression model has beeb estimated employing the certain policy variables to investigate the dynamics of currency substitution in the economy. Dynamic impulse responses show that the residents have a preference for substitutiong foregn currencies for domestic currency because of reawl-exchange-rate depreciations. The results suggest that to stop or to reverse the on-going currency substition process a plicy aiming to increase the expected real return on domestic assets should be adopted.

On the macroeconomic impact of the August 1999 earthquake in Turkey: a first assessment

The devastating earthquake that struck the most densely populated and industrialized area of Turkey on 17 August, 1999 was one of the most damaging natural disasters during this century. This paper is a first attempt to estimate the transition path of the Turkish economy to its new equilibrium after the earthquake. An applied general equilibrium model is utilized to provide an initial assessment and to obtain the second best policy options to mitigate the negative effects of the earthquake. The analytical foundations of the model rest upon intertemporal dynamics as laid out in neoclassical growth theory. Simulation results suggest that the initial impact of the earthquake on GDP may range from −4.5% to + 0.8% of GDP, conditional upon policies followed by the government and international donors. The policy implication of the paper is that best outcomes might be reaped via a negative indirect tax (a subsidy financed by foreign aid) to individual sectors to recover their capital losses. On the other hand, an indirect tax to finance the extra fiscal spending would result in an output loss, further deepening the impact of the earthquake on the economy.

Asymmetric stochastic volatility in emerging stock markets

Daily stock market volatility in a sample of emerging market economies is investigated utilizing an asymmetric stochastic volatility (ASV) model which is estimated with Markov Chain Monte Carlo (MCMC) method. The results indicate that the ASV model captures the volatility dynamics in those stock markets successfully. Particularly, it is shown that volatility has a significant persistency and the variability of volatility is higher as compared to advanced economies. The paper also provides evidence for significant negative correlation between shocks to the stock market index and shocks to volatility, the so-called ‘leverage effect’. Furthermore, the estimation results show that the persistency in volatility and the variability of volatility are negatively related: higher variability of volatility implies lower persistency in volatility series and vice versa. In addition, persistency in volatility and the magnitude of leverage effect are negatively correlated: high persistency is associated with relatively lower leverage effect.

Currency Substitution: New Evidence from Emerging Economies

This paper provides new empirical evidence for currency substitution in different emerging market economies. Estimation results from a money-in-the-utility-function framework indicate that foreign currencies are strong substitutes for domestic currency in producing liquidity services.

The dynamics of a newly floating exchange rate: the Turkish case

In recent years, many emerging market economies have switched or are in the process of switching to a floating exchange rate regime. Most of these economies have a history of high inflation and a high level of foreign currency denominated debt. Therefore, the stability of the exchange rate and the dynamics of its volatility are more crucial than before. This paper analyses the dynamics of exchange rate in Turkey in the aftermath of recent float in February 2001. The Turkish experience is a particularly important one, and provides valuable lessons for other countries as the Central Bank is trying to simultaneously contain the volatility of exchange rate and pursue an implicit inflation targeting policy. The reported findings indicate that the Central Bank policies, accompanied with favourable external factors, were effective in taming the volatility of the exchange rate in a relatively short period of time. However, there is a significant real appreciation of the currency during the same period. Given the high level of public debt and real interest rates, the current state of the economy is very susceptible to any adverse shocks.

When Do Informed Traders Arrive in Foreign Exchange Markets

This article examines the implications of the existence of private information in the spot foreign exchange market. Our framework is a high-frequency version of a structural microstructure trade model that measures the market makers beliefs directly. We find that the underpinnings for the time-varying pattern of the probability of informed trading are rooted in the strategic arrival of informed traders on a particular hour-of-day, day-of-week, and geographic location (market). Specifically, we document that informed traders not only pick the low activity hours, but also attach the largest market weight to a particular market. The distributions of the estimated arrival rates confirm the commitment of the informed traders to strategic trading activities. In our framework, we acknowledge that an expected loss of informed trading to the market maker is a function of both the probability of informed trading and its likely impact on the price. The impact of the uninformed traders arrival on the daily foreign exchange price volatility is about twice the magnitude of the one for informed traders. These effects are in stark contrast to the findings from the hourly data that indicate dominance of informed traders. Finally, the results relate the informational content of trading to the trade size and suggest that the probability of the informed large trading is significantly higher than the probability of uninformed large trading.

The Policy Challenge at Floating Exchange Rates: Turkey's Recent Experience

This paper evaluates the developments in the Turkish economy in light of the Central Banks policies during a recent period of floating exchange rate system. It is found that the Central Bank was effective in containing volatility and reducing the average inflation rate while there was a strong recovery of the output. However, there are accumulated risks in the economy. Particularly, the extreme appreciation of the Turkish lira during this period and the record level of real interest rates give the impression that the current state of the economy is fragile. Unless the government accelerates structural reform process and pursues sound fiscal policies to reduce the public sector borrowing requirement and the debt ratio, any adverse shock to the system may trigger a reversal of fortune.

A Visual Goodness-of-Fit Test for Econometric Models

This paper designs a visual goodness-of-fit test based on the probability integral transformation of the residuals of an estimated model. We illustrate the method with histograms and correlograms of transformed series for different distributions of disturbances in simulated models. An application of the proposed test to the modeling of daily stock-market returns is also presented.