NO.PZ201712110200000507
问题如下：
Based on the three economic outlook statements, a profitable long/short trade would be to:
选项：
A.go long a Canadian CDX IG and short a US CDX IG.
B.short an iTraxx Crossover and go long an iTraxx Main.
C.short electric car CDS and go long traditional car CDS.
解释：
B is correct.
Based on Outlook 1, Chan and Smith anticipate that Italy’s economy will weaken. In order to profit from this forecast, one would go short (buy protection) a high-yield Italian CDS (e.g., iTraxx Crossover) index and go long (sell protection) an investment-grade Italian CDS (e.g., iTraxx Main) index.
老师，没太理解这里的long short如何带来收益
A选项，按解析是错误的，那正确的应该是short Canadian CDX, long US CDX.
我理解的是，Canada经济相对US更差，那Canadian CDX的spread应该更大，那如果买CDX就需要pay更多的钱，相对卖US的CDX只能receive更少的钱。
这样的long/short如何带来收益呢？
