
ãä»å ¥æ¿çæ¹éã®è»¢æðããJapanese Foreign Exchange Interventions, 1971-2018:Estimating a Reaction Function Using the Best ProxyãïŒå è¡ç 究解説 No.11ð2023/10/30
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ãJapanese Foreign Exchange Interventions, 1971-2018: Estimating a Reaction Function Using the Best Proxyã
Takatoshi Ito(a), Tomoyoshi Yabu(b)
(a) School of International and Public Affairs, Columbia University, and GRIPS, Tokyo
(b) Department of Business and Commerce, Keio University
Japanese Foreign Exchange Interventions, 1971-2018: Estimating a Reaction Function Using the Best ProxyÂ
December 12, 2019
Takatoshi Ito(a), Tomoyoshi Yabu(b)
(a) School of International and Public Affairs, Columbia University, and GRIPS, Tokyo
(b) Department of Business and Commerce, Keio University
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4. Patterns of intervention
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Table 4 shows the details of interventions by fiscal year (April to March): intervention frequencies (the number of months), intervention (cumulative) amounts (by fiscal year), and the average (per month) magnitude of interventions (year total divided by the number of intervention months).
This clearly shows that the frequency has declined, but also that the per-month magnitude has become larger since 1995. Prior to 1995, there were 178 months featuring intervention, amounting to 46 trillion yen in total.
Thus, average per-month intervention was 258 billion yen. After 1995, interventions occurred during 41 months, with intervention totals reaching 78 trillion yen. The average per-month intervention amount was 1.9 trillion yenâmore than 7 times the amount before 1995.
Neely (2011) described and examined the fact that interventions had become infrequent over time in major countries: frequent interventions were ceased in the UK in 1993; in the US, Germany, and Switzerland in 1995; in Canada in 1998, and in Japan in March 2004.

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Fig. 4 shows the changing ceiling and floor exchange rates for intervention over time.
The last selling rate is the yen/dollar rate when the dollar was sold by the Japanese monetary authorities, while the last buying rate is the yen/dollar rate when the dollar was bought by the Japanese monetary authorities.
The band between the two prices implies the tolerance range, or target zone, for the fluctuation of the exchange rate for the authorities.
Between 1971 and 1990, both the ceiling and floor of the tolerance band shifted gradually toward yen appreciation. The figure shows that the Japanese authorities had a moving band of symmetric interventions.
Although the band shifted over time, the floor and ceiling had a significant spread most of the time. Until 1992, interventions were symmetric, but the range had shifted, gradually allowing for a long-run trend of yen appreciation.

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The above figure shows that after 1991, the last selling rate consistently remained above 125, while the last buying rate stayed below 125.
Since the last dollar-selling intervention was in 1998, the last selling rate has not changed.
Since 1991, the last buying rate only went down toward the appreciated level, while the last selling rate only went up toward the depreciated level.
Thus, the tolerance band has widened to the range of 77.5-140.6, which is a spread of 63 yen.
Intervention became more unilateral after 1998, only changing the point of intervention on the appreciation side, mitigating the speed of yen appreciation and defending the particular level, such as 75 to 80 yen per dollar in 2010-12.

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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)
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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