
ãGARCHã¢ãã«ã«ããç¹å®ðããThe Effects of Japanese Foreign Exchange Intervention: GARCH Estimation and Change Point DetectionãïŒå è¡ç 究解説 No.8 2023/09/22
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ãThe Effects of Japanese Foreign Exchange Intervention: GARCH Estimation and Change Point Detectionã
Eric Hillebrand Gunther Schnabl Discussion
Paper No.6 October 2003
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çµæžç ç©¶ãVol.54 No.2 Apr. 2003
ãEffects of the Bank of Japanâs intervention on yen/dollar exchange rate volatilityã21 November 2004
Toshiaki Watanabe (a), Kimie Harada(b)
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The Effects of Japanese Foreign Exchange Intervention: GARCH Estimation and Change Point Detection
Eric Hillebrand Department of Economics, Louisiana State University
Gunther Schnabl Department of Economics and Business Administration, Tuebingen
4.1. Specification
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This leads to the following GARCH specification:
éèšããããŒã¿ã«åºã¥ããšãããã¯GARCHã¢ãã«ã«ããç¹å®ãå°ããŸã
以äžã«ããã®å
è¡ç ç©¶ã§åãäžããããŠããGARCHã¢ãã«(1)~(3)åŒã®æ§é ãå®åŒåããŸãð
以äžã§ã¯ããã®ã¢ãã«ã«å¯Ÿãã説æãããŠããããšã«ããŸã
In equation (1) rt denotes the logarithmic returns of the yen/dollar spot exchange rate (conditional mean) as plotted in the upper left panel of Figure 3.
The exchange rate is assumed to be influenced by official foreign currency transactions I.
The deviation of the exchange rate from a certain bliss point increases the probability of foreign intervention as suggested by Figure 4 and shown by Frenkel, Pierdzioch and Stadtmann (2003a).
It precedes unambiguously the exchange rate changes measured at 5 p.m. Greenwich time, as Japanese foreign exchange intervention is performed in the Japanese markets and US intervention is negligible.
GARCHã¢ãã«ãæ§æããåŒ (1) ã®rtã¯ãå³3ã®å·Šäžã®ããã«ã«ãããããããŠããå/ãã«ã®ã¹ãããçºæ¿ã¬ãŒã (æ¡ä»¶ä»ãå¹³å) ã®å¯Ÿæ°ãªã¿ãŒã³ã瀺ããŠããŸã

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¥é¡ïŒ Iã®åœ±é¿ãåãããšæ³å®ããŠããŸã
ãŸããå³4ã§ããFrenkelãPierdziochãStadtmann(2003a)ãã«ãã£ãŠç€ºãããŠããããã«ãçºæ¿ã¬ãŒããç¹å®ã®è³é«ç¹(bliss point)ããä¹é¢ãããšãå€åœä»å
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As proposed by Bonser-Neal and Tanner (1996) we include the daily returns of Japanese and US stock marketsâNikkei 300 and DOW Jones Industrialâas exogenous variables to control for the impact of disturbances in other asset markets.
We do not include any dummies for the announcement of interest rate changes, since prior estimations with dummies did not yield any significant results.
In contrast to Dominguez (1998) and Baillie and Osterberg (1997) we do not include dummy variables for the day of the week and holidays for the sake of brevity.
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è¡ç ç©¶ã§ã¯ãBonser-NealãšTanner(1996)ãææ¡ããããã«ãä»ã®è³ç£åžå Žã«ãããæ··ä¹±ã®åœ±é¿ãå¶åŸ¡ããããã®å€ç倿°ãšããŠãæ¥æ¬ãšç±³åœã®æ ªåŒåžå Ž (æ¥çµ300ãšDOWãžã§ãŒã³ãºå·¥æ¥)ã®æ¥ã
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Dominguez(1998)ããã³Baillieããã³Osterberg(1997)ãšã¯å¯Ÿç §çã«ãç°¡æœã«ããããã«ãææ¥ãšäŒæ¥ã®ãããŒå€æ°ã¯å«ããŠããŸããð
In equation (2) the disturbances εt are modelled as normally distributed conditional on the information set âŠt-1 available at time t-1, with zero mean and variance ht.
Equation (3) models the volatility of the yen/dollar exchange rate as plotted in the lower left panel of Figure 3.
The variance ht depends on past disturbances εt-i, the lagged variance ht-j, the absolute official foreign currency intervention |It|, and the volatility in the Japanese and US share markets defined as the squares of daily returnsâ  Nikkei_t^2 and DOW_t^2.
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