问题如下：
Wang is a fixed-income analyst in a securities firm. One of his clients based in US invests in US and German corporate bonds. Suppose the currency risk is hedged. Wang believes that over the next 12-month, the interest in US will decline relative to that of German. Besides, in the US corporate market, the difference between average credit spread of 3-year BB corporate bonds and the average credit spread of 1-year BB corporate bonds will narrow.
According to the information above, which of the following strategy should Wang recommend to his client?
选项：
解释：
A is correct.
考点：考察相对利率变动时对应的投资
解析：投资于预期收益率相对下跌的市场可以获得更多Return；Wang预测美国债券市场的收益率相对于德国债券市场的收益率下跌，因此Overweight美国市场的债券,Underweight德国市场的债券，可以获得更高的收益；因为收益率相对下跌，意味着可以获得相对的Capital gain，以增强投资收益。所以在此预期下，可以overweight US bonds，并且Underweight German bond；同时预测在美国市场，BB级债券，3年期B的Average credit Spread，和1年期BB级债券Average credit Spread之间的差距在缩小，也就是说3年期的Average credit spread相对变小，因此再此预期下，可以overweight3年期的债券，Underweight 1年期的债券，获得相对更高的收益。
还是不太明白，为什么三年期的相对spread 变小，的情况下要overweigt
是相对spread变小所以卖出价格更高？收益率更高？
