通貨切り下げ競争は無意味？
通貨切り下げ競争をすれば流動性が高まり景気回復するというのは、金本位制の話であって、現代では無意味、とクルーグマンが言っている。
例えば、日本が円を売りドルを買うとする。アメリカはドルを売ってユーロを買う。欧州はユーロを売って円を買う。これでは同じ量のお金が世界をぐるぐる回るだけなので、何の効果もない。
クルーグマンは、為替市場への介入は流動性同士を取引しているだけなので、世界中の流動性が増えるわけではないことを指摘している。しかし、自国通貨を売って得た外貨で外国の正の金利がついた債券を買えば、金融緩和になるから効果がある。と言っている。それはそうだ。
で、自国の長期債を購入しないのに外国の長期債を購入するわけないじゃないか、と言っている。
しかし、それぞれの国は内貨を売って得た外貨で外国の長期債とか買ってますよね。金融緩和していることになるんじゃないのかな。
それは日本や中国だけの話か。
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http://krugman.blogs.nytimes.com/2010/10/04/a-note-on-currency-wars/
＜I’ve seen a number of people — most recently, Yglesias — suggesting that mutual attempts by major economies to depreciate their currencies could be really helpful right now. The intuition seems clear: it gets countries printing money; and there’s also the historical argument by Eichengreen that competitive devaluation in the 1930s was actually quite helpful.
But I don’t think this argument really works — at least not as phrased. The hypothesized currency war in which the Fed buys euros and the ECB buys dollars might not do any harm, but it probably wouldn’t help, either.
Why? In the 1930s, competitive devaluation mattered largely because a number of countries were still on the gold standard, and were keeping interest rates well above the zero lower bound in an attempt to preserve their gold reserves. Devaluation relaxed this constraint by making the gold worth more in domestic currency, and hence was expansionary.
Today there’s nothing like that, and rates are pretty much at zero. And in that case, it’s hard to see what mutual intervention accomplishes. Suppose the Fed buys a bunch of euros, and the ECB a bunch of dollars. Suppose also that they do the usual thing and hold the newly acquired reserves in short-term debt — Treasury bills. Then the net effect is just as if each central bank had done a conventional open-market operation in its own T-bills.
And the whole point of the liquidity trap literature is that such conventional open-market operations have no effect — they just swap one zero-rate asset, monetary base, for another, short-term government debt. So the currency interventions accomplish nothing.
It would be different if the central banks acquired long-term assets instead; then we’re talking about quantitative easing through the back door. But I see no reason to believe that central banks reluctant to buy domestic long-term debt will be more willing to buy foreign long-term debt.
So a wave of mutual currency purchases would be harmless but also pointless.＞
例えば、日本が円を売りドルを買うとする。アメリカはドルを売ってユーロを買う。欧州はユーロを売って円を買う。これでは同じ量のお金が世界をぐるぐる回るだけなので、何の効果もない。
クルーグマンは、為替市場への介入は流動性同士を取引しているだけなので、世界中の流動性が増えるわけではないことを指摘している。しかし、自国通貨を売って得た外貨で外国の正の金利がついた債券を買えば、金融緩和になるから効果がある。と言っている。それはそうだ。
で、自国の長期債を購入しないのに外国の長期債を購入するわけないじゃないか、と言っている。
しかし、それぞれの国は内貨を売って得た外貨で外国の長期債とか買ってますよね。金融緩和していることになるんじゃないのかな。
それは日本や中国だけの話か。
*********************************************************
http://krugman.blogs.nytimes.com/2010/10/04/a-note-on-currency-wars/
＜I’ve seen a number of people — most recently, Yglesias — suggesting that mutual attempts by major economies to depreciate their currencies could be really helpful right now. The intuition seems clear: it gets countries printing money; and there’s also the historical argument by Eichengreen that competitive devaluation in the 1930s was actually quite helpful.
But I don’t think this argument really works — at least not as phrased. The hypothesized currency war in which the Fed buys euros and the ECB buys dollars might not do any harm, but it probably wouldn’t help, either.
Why? In the 1930s, competitive devaluation mattered largely because a number of countries were still on the gold standard, and were keeping interest rates well above the zero lower bound in an attempt to preserve their gold reserves. Devaluation relaxed this constraint by making the gold worth more in domestic currency, and hence was expansionary.
Today there’s nothing like that, and rates are pretty much at zero. And in that case, it’s hard to see what mutual intervention accomplishes. Suppose the Fed buys a bunch of euros, and the ECB a bunch of dollars. Suppose also that they do the usual thing and hold the newly acquired reserves in short-term debt — Treasury bills. Then the net effect is just as if each central bank had done a conventional open-market operation in its own T-bills.
And the whole point of the liquidity trap literature is that such conventional open-market operations have no effect — they just swap one zero-rate asset, monetary base, for another, short-term government debt. So the currency interventions accomplish nothing.
It would be different if the central banks acquired long-term assets instead; then we’re talking about quantitative easing through the back door. But I see no reason to believe that central banks reluctant to buy domestic long-term debt will be more willing to buy foreign long-term debt.
So a wave of mutual currency purchases would be harmless but also pointless.＞
