Flip From AI Rally Chase to Bubble Fear Spurs Options Demand

No matter which way the S&P 500 Index goes after a tumultuous month, options volatility looks to be headed higher.

The benchmark snapped a three-week run of gains, pushing for a time on Friday the Cboe Volatility Index well above 20, a sign of growing market stress. The pullback in stocks reversed an acceleration to a record high that saw an increase in spot up, vol up days — when share prices and volatility move in tandem, as opposed to the typical inverse relationship between the two.

A number of factors supported volatility flare-ups in mid-October and last week. ...