问题如下：
What protection is obtained when a Treasury bond futures contract is used to hedge a bond portfolio using duration analysis? What assumptions are necessary?
选项：
解释：
The hedge protects against small parallel shifts in the zero curve. The following assumptions must be made:
the cheapest-to-deliver bond is known and movements in the rates to which the portfolio is exposed are very similar to movements in the corresponding Treasury rates.
老师你好，这块是哪的知识点？能解释一下吗谢谢
