You have a long position in a digital call option -- an option that is also called cash-or-nothing -- on shares in Global Enterprises. The digital call has a strike price of USD 20 with one year remaining to expiration. Assume that the shares currently trade at USD 22 and annual return volatility of Global Enterprises shares is 15%. Which of the following sensitivities would be associated with this option? Ⅰ Delta is positive. Ⅱ Gamma is positive. Ⅲ Vega is negative. Ⅳ Vega is positive. Which statements are true? A. Ⅰ and Ⅲ B. Ⅳ only C. Ⅰ,Ⅱ and Ⅳ D. Ⅱ and Ⅲ 完全不会，请详细讲解，谢谢老师

为什么说var可以确定组合的关键风险因素？

561题完全不懂，麻烦老师给解析一下，谢谢！

老师 能不能解释下为什么D是对的？不是应该R方表示解释程度吗

老师，假设有一个每半年付50的年金，年利率是8%，三个月后就卖出了，要计算此时的clean price。我的解题方法是这样的，为什么用计算器按出来的结果跟公式算出来的结果不一样呢？我哪个数错了吗？还是我公式用错了呢？

老师，请问lending不是借出，borrowing借入嘛，借出应该是负号，借入为正号？

想请么峥老师推荐这本讲解保时捷和大众公司收购和反收购案例的书。谢谢。

439题答案选A但是流程不太懂，是买第三只债券同时卖前两只债券，还是有先后顺序？

W1+w2=1的？

X 折现两个半年？