Mid-session market 03/17: Fear returns on $2.9 trillion OpEx day

US stock market has a volatile end-of-week session as morning gamma expiration concentrated mostly at 390/3900 ~ SPY/SPX gradually disappears. OpEx impact on flow not overly significant as options on both sides nearly volatility crushed heavily over the past 4 days, with macro uncertainties forcing investors to roll hedges early to cover next week's FOMC and banking sector events.