Better develop reflexes — Across all maturities, all ITM/OTM options’ delta would converge towards 50% when perceived and implied volatility intensifies. Option premium rises.
50 delta means ATM.
50 delta also means no-prediction about my option finishing ITM or OTM. When vol spikes, it becomes harder for “gamblers” to assess any given strike — will it finish ITM or OTM?
Let’s use a put for illustration. When underlier becomes very volatile,
– a previously deep OTM (hopeless) suddenly looks a useful insurance protection. eg – A ultra-low-strike put.
– a previously deep ITM (sure-win) suddenly looks “unsafe” — may finish worthless.
Rule) At expiry, underlier volatility doesn’t bother us and is treated as 0
Rule) At expiry, option delta == either 0 or 1/-1 never something else. Fully diverged
Rule) In general, 0 implied volatility means all options’ deltas == either 0 or 100%
Rule) Similarly low implied volatility means all options’ deltas are close to the 2 extremes.