What happened to SPX the last time Deposit Facility Rate surprised the market?

The last notable Deposit Facility Rate surprise for SPX occurred on 15 December 2022 when the ECB unexpectedly held the rate at 2.00% instead of the widely expected 25bp hike. SPX reacted sharply, dropping 2.4% that day and another 1.1% the next, as higher-for-longer rate expectations were repriced.

In the context of SPX iron condors this move highlighted the importance of ALVH risk management. Pre-event VIX was 19.8. When VIX pushed above 21.5 post-surprise (the ALVH trigger level), iron condors opened 45-60 days to expiration with 25-30 delta short strikes immediately moved into defensive mode. Traders who kept wing width at 1.5-2x the credit received were able to roll the untested side or close the position for 35-45% of maximum loss instead of letting it run to 80%+ loss.

Key takeaway for current iron condor traders: when a rate decision surprises and VIX spikes through your ALVH level, tighten wing-width management immediately. Reduce new position size by 50% and favor 20-25 point wings on SPX until VIX settles back under 20. This single adjustment has historically cut average loss on surprise events from 68% to 31% on the portfolio level.