做多跨式：想要什么样的价格波动

Long a straddle

You are long a straddle with a strike of $25$ .
The underlying is currently at $25$ .
The straddle costs you $5$ to enter.

What price movement are you looking for in the underlying?

解析

做多 straddle = 买入同到期同执行价的 call + put。

执行价 $K=25$ ，成本 5，因此到期盈亏平衡点为

S_T=K\pm 5 \Rightarrow 20\ \text{和}\ 30.

所以你希望标的价格大幅波动，即

\boxed{S_T<20\ \text{或}\ S_T>30}\quad\text{（波动越大越好）。}