NO.PZ2023041102000017
问题如下：
Thibodeaux notes that current account trends influence the path of exchange rates over time through several mechanisms
“Of the three mechanisms that economists identify, I have the most confidence in the one that assumes there are long-run limits on current account deficits.”
The mechanism about which Thibodeaux is most confident as an explanation for the long-run equilibrium value of exchange rates is best described as the:
选项：
A.debt sustainability channel. B.flow supply/demand channel. C.portfolio balance channel.解释：
A is correct. Thibodeaux prefers the debt sustainability channel as a means to assess the long-run equilibrium value of exchange rates. According to this mechanism, there should be some upper limit on the ability of countries to run persistently large current account deficits. If a country runs a large and persistent current account deficit over time, eventually it will experience an untenable rise in debt owed to foreign investors. If such investors believe that the deficit country’s external debt is rising to unsustainable levels, they are likely to reason that a major depreciation of the deficit country’s currency will be required at some point to ensure that the current account deficit narrows significantly and that the external debt stabilizes at a level deemed sustainable.
B is incorrect. The flow supply/demand channel mechanism focuses on the fact that purchases and sales of internationally traded goods and services require the exchange of domestic and foreign currencies in order to arrange payment for those goods and services. Such shifts in currency demand should exert upward pressure on the value of the surplus nation’s currency and downward pressure on the value of the deficit nation’s currency.
C is incorrect. The portfolio balance channel assumes that current account imbalances shift financial wealth from deficit nations to surplus nations. Countries with trade deficits will finance their trade with increased borrowing. This behavior may lead to shifts in global asset preferences, which in turn could influence the path of exchange rates.
题干中“Of the three mechanisms that economists identify, I have the most confidence in the one that assumes there are long-run limits on current account deficits.”
应该是关于Macroeconomic balance approach的表述，但为什么最后选择External sustainability approach呢？
