IV Rank（隐含波动率分位）

中文解释

IV Rank 会把当前隐含波动率和它自身的历史区间进行比较。高 IV Rank 表示当前 IV 接近历史区间上沿，低 IV Rank 表示更接近区间下沿。交易者常用它判断期权权利金相对历史是否偏贵或偏便宜，但 IV Rank 本身不预测方向。

English definition

IV Rank compares current implied volatility with its own historical range. A high IV Rank means current implied volatility is near the upper part of that range, while a low IV Rank means it is closer to the lower part. Traders use IV Rank to frame whether option premium looks elevated or compressed relative to recent history, but it does not predict direction by itself.

在 Nightwatch 里怎么看

Nightwatch 的 IV 波动率页提供 IV Rank，并把各到期日的隐含波动率画成一条期限结构曲线，用来判断期权现在相对自身历史是贵还是便宜。IV Rank 不预测方向。

The Nightwatch IV page shows IV Rank and plots implied volatility across expiries as a term-structure curve, to judge whether options are rich or cheap relative to their own history. IV Rank does not predict direction.