
ãä»å ¥ã«äŒŽãã³ã¹ããšå°æ¥ã®äºæž¬ðããJapanese Foreign Exchange Interventions, 1971-2018:Estimating a Reaction Function Using the Best ProxyãïŒå è¡ç 究解説 No.14ð2023/11/02
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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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5. Reaction Function
ååã®æçš¿ã§ã¯ãé åºãããããã¢ãã«(Ordered Probit Model)ãçšããŠãé貚åœå±ã®åå¿é¢æ°ãæ±ããããã»ã¹ã«ã€ããŠã¢ãŠããããããŸããð
Ito and Yabu (2007)ã¯ãç®æšçºæ¿ã¬ãŒããšä»å
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Ito and Yabu (2007)ã®é åºä»ããããããã¢ãã«ãä»äžåºŠã埩ç¿ããšããŠç¢ºèªããŠããããšã«ããŸããã
5.4. Ordered Probit Regressions
Table 6 presents the estimated results of the ordered probit model Eq. (2) for each subsample.
When these results are compared with the ones from the linearized model in section 5.3, the signs of the estimated coefficients and their significances are almost the same.
Consequently, we only discuss estimates of new parameters in the ordered probit model:µ*1 and µ*2 , which respectively represent the cost of dollarselling interventions and the cost of dollar-buying interventions.
Note that in the last two periods, there was no dollar-selling intervention at all and thus, the parameter µ*1 is not estimated in the regression.
衚6ã¯ãé åºä»ããããããã¢ãã«ã®åŒ(2)ã®æšå®çµæã瀺ããŠããŸã
åãµããµã³ãã«ã«ã€ããŠããããã®çµæãã»ã¯ã·ã§ã³ 5.3 ã®ç·åœ¢åã¢ãã«ã®çµæãšæ¯èŒãããšãæšå®ä¿æ°ã®ç¬Šå·ãšãã®æææ§ã¯ã»ãŒåãã§ãð

ãããã£ãŠãé åºä»ããããããã¢ãã«ã®æ°ãããã©ã¡ãŒã¿ãŒã®æšå®å€ã®ã¿ã説æããŸã
µ1*㚠µ2*ã¯ããããããã«å£²ãïŒåè²·ãïŒä»å
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¥ããŸã£ãããªãã£ãããããã©ã¡ãŒã¿ µ*1ã¯ååž°ã§ã¯æšå®ãããŠããªãããšã«æ³šæããŠããŸãð
In the first period, µ1* is significantly negative while µ2* is not significantly different from zero.
The monetary authorities were accordingly more inclined to buy rather than sell dollars due to the difference in cost.
This point was also raised by Hutchison (1984).
For the second period, the parameter µ2* is significantly positive. Due to international political pressure, it might have been difficult for the monetary authorities to purchase dollars to induce yen depreciation.
The parameter µ1* is significantly negative and larger in terms of absolute values than the corresponding parameter from the first period, which means that there was a higher cost for dollar-selling interventions.
Moreover, µ2* is larger than µ*1 in terms of absolute values and thus, the cost of dollar-buying interventions was higher than the cost of dollar-selling interventions.
The monetary authorities are more inclined to resist yen depreciation than yen appreciation.
The neutral band of no intervention is wider here than that of the first period.

æåã®æé(1971/8~1981/11)ã§ã¯ãÎŒ1*ã¯å€§å¹
ã«è² ã§ãããÎŒ2*ã¯ãŒããšå€§ããç°ãªããŸãã
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ãã®ç¹ã¯ Hutchison (1984) ã«ãã£ãŠãæèµ·ãããŠããŸã
ç¶ããŠã2çªç®ã®æé(1981/12~1995/5)ã§ã¯ããã©ã¡ãŒã¿ãŒ µ2*ã¯å€§å¹
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åœéçãªæ¿æ²»çå§å(international political pressure)ããããéèââåœå±ãåå®ãèªå°ãããã«è²·ãïŒå売ãïŒãããã®ã¯é£ããã£ãã®ãããããªããšããèå¯ãã§ããŸãïŒâ»è¿é£çª®ä¹åæ¿çã«ããåŒå®³ãªã©ãèæ
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ãŸããã©ã¡ãŒã¿ µ1* ã¯å€§å¹
ã«ãã€ãã¹ã§ããã第1æéã®å¯Ÿå¿ãããã©ã¡ãŒã¿ããã絶察å€ââã倧ãããªã£ãŠããããšãèªã¿åããŸã
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¥ãªãã®äžç«åž¯å(The neutral band of no intervention)ã¯ãããã§ã¯æåã®æéãããåºããªã£ãŠããããšãããããŸãð
For the third period, both parameters µ1* and µ2* are significantly different from zero.
Moreover, µ1* is larger than µ2* in terms of absolute values and thus, the cost of dollar-selling interventions was larger than the cost of dollar-buying interventions.
The monetary authorities were more inclined to prevent yen appreciation than yen depreciation, and the neutral band of no intervention was even wider than that of the second period.
Note that µ2* is lower than the corresponding parameter for the second period, which means that the cost of dollar-buying interventions becomes lower in this period.
3çªç®ã®æé(1995/6~2002/12)ã§ã¯ããã©ã¡ãŒã¿ãŒ µ1*ãšÂµ2*ã®äž¡æ¹ããŒããšã¯å€§ããç°ãªããŸãð
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For the fourth period, µ2* is not significantly different from zero.
Therefore, there is no evidence of a neutral band, which means that there was no international political pressure from other countries when the monetary authorities intervened in the foreign exchange market.
As Taylor (2006), who served as the Under Secretary of the Treasury for International Affairs during the George W. Bush administration, documented, the US Treasury has been critical of interventions but approved Japanese interventions during this period in order to show support for the quantitative easing policy adopted by the Bank of Japan. (See Taylor, 2006 for details).
In fact, Watanabe and Yabu (2013) found that when yen-selling interventions supplied yen funds to the market, the Bank of Japan offset 60% of the yen funds through market operations, while the remainder remained in the market for a while.
4 çªç®ã®æéã§ã¯ãÎŒ2* ã¯ãŒããã倧ããå€ãããŸããããããã£ãŠãä»å ¥ãªãã®äžç«åž¯å(The neutral band of no intervention)ã®èšŒæ ã¯ãªããããã¯é貚åœå±ãå€åœçºæ¿åžå Žã«ä»å ¥ãããšãã«ä»åœããã®åœéæ¿æ²»çå§åããªãã£ãããšãæå³ããŸã

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¥ã«ã¯æ¹å€çã ã£ãã®ã§ããããã®æéäžãæ¥æ¬éè¡ãæ¡çšããéçç·©åæ¿ç(the quantitative easing policy)ã«å¯ŸããŠç±³åœãžã®æ¯æã瀺ãããã«æ¥æ¬ã®ä»å
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¥ã«ãã£ãŠåžå Žã«åè³éãäŸçµŠããããšããæ¥éã¯åžå Žèª¿ç¯ãéããŠåè³éã®60%ãçžæ®ºããæ®ãã¯ãã°ããåžå Žã«çãŸã£ãããšïŒïŒéäžèåä»å
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On the other hand, for the fifth period, µ2* has the largest value of 8.405. Hence, its neutral band was the widest among all subsamples. This is because interventions took place only on rare occasions, such as when the yen appreciated sharply due to the Great East Japan Earthquake in March 2011 and when the yen/dollar rate appreciated to 75 yen per dollar, setting a historical record in August 2011.
Therefore, the monetary authorities were not able to intervene in the market due to international political pressure, except in cases when it was clear that excess volatility and disorderly movements in the yen/dollar rate would damage economic and financial stability.
In contrast to the results in the linear regression, this period has higher explanatory power (pseudo R^2) than other periods.
This is due to the fact that the model is now rich enough to predict zero intervention by introducing a neutral band of no intervention.
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