
ãçè«ãšå®èšŒãšã®ä¹é¢ðŒããThe Effects of Japanese Foreign Exchange Intervention: GARCH Estimation and Change Point DetectionãïŒå è¡ç 究解説 No.6 2023/09/20
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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. GARCH ESTIMATION
To measure the short-term impact of foreign exchange intervention on both the level and volatility of the yen/dollar rate we use a GARCH model with exogenous intervention data in both the conditional mean and variance equations as proposed by Engle (1982), Bollerslev (1986), and Baillie/Bollerslev (1989).
Prior studies have defined volatility in different waysâlong-term movements of exchange rate prices as plotted in Figure 4 and percentage exchange rate changes, e.g. absolute or squared returns, as plotted in Figure 5 for daily data.
For instance, the Louvre-target zones between dollar, yen and German mark (established in February 1987) were intended to reduce exchange rate volatility in terms of long-term movements of exchange rate prices.11 This implies that intervention took place when the exchange rate approached a certain exchange rate (price) level.
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Similarly, Japanese foreign exchange intervention tried to prevent the yen from falling to above about 150 yen/dollar in 1998, rising above about 105 yen/dollar in 1999/2000, 117 to 120 yen/dollar in 2001, or 115 to 122 yen/dollar in spring 2003.
We interpret these attempts to smooth the long-term movements as targeting the exchange rate level. The impact of foreign exchange intervention on the exchange rate level is captured by the mean equation of our GARCH model.
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In contrast, Dominguez (1998) defines volatility as squared returns.
There are two possible directions of causality between such short-term exchange rate volatility and foreign exchange intervention.
In liberalized foreign exchange markets exchange rate volatility is high because of a large number of private foreign exchange transactions.
Ifâas observed in many countries with hard or soft peg exchange rate arrangementsâmonetary authorities want to reduce this exchange rate volatility substantially, intervention is conducted on a day-to-day basis. Exchange rate volatility triggers intervention.
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In contrast, the central banks of the large industrial countries (Federal Reserve, European Central Bank, Bank of Japan) operate under monetary policy frameworks that target and smooth short-term interest rates.
Exchange rates float freely.
To sustain the interest rate target, foreign exchange intervention can take place only infrequently and on a discretionary basis.
As per definition foreign exchange intervention remains erratic and mainly unexpected, the causation is probable to run from intervention to volatility rather than vice versa.
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