Standard daily price range estimate for SPX options strike placement
Definition
The projected daily price range for SPX calculated from VIX. Used alongside EDR for strike selection and risk assessment in all SPX Mastery strategies. The Expected Move represents a one-standard-deviation range — meaning SPX statistically stays within this range approximately 68% of trading days.
Formula / Rules
EM ≈ SPX × (VIX / 100) / √252
Example: SPX = 5,800, VIX = 16.57 → EM ≈ $60.6 (±$60.6 for the day)
How It Works
The Expected Move serves as the baseline range estimate before EDR refinement. It is calculated from current SPX price and VIX, divided by the square root of 252 (trading days). EDR then applies multipliers (0.8–2.0) to this baseline to produce tier-specific strike recommendations. The EM is checked as part of the pre-close scan: if EDR × SPX produces a tight expected range and VIX is below 15, aggressive High-tier Iron Condors are appropriate. If EDR is elevated (> 0.94% of SPX), the Temporal Theta Martingale forward-roll trigger is activated.
Expected Move ≈ SPX Price × (VIX / 100) ÷ √252. For example, at SPX 5,800 and VIX 16.57, the daily EM is approximately ±$60.6. This represents the one-standard-deviation daily range statistically expected 68% of trading days.
APA Citation
Clark, R. (2025). SPX Mastery: Iron Condor Command – Daily Cash from Market-Close Trades. Diva Dog Press.
RC
Russell Clark, FNP-C
Author of SPX Mastery series · Founder of VixShield
Last updated:
· Source: VixShield Trading Glossary — From SPX Mastery by Russell Clark
⚠️ Not financial advice. This definition is educational content from the SPX Mastery book series by Russell Clark (VixShield). Past performance is not indicative of future results. Trading options involves substantial risk of loss and is not appropriate for all investors. Always paper trade before risking real capital.