S&P 500 Index (SPX · index)
Overview · Option chain · Volatility · Expected-move history
Cboe delayed options data · as of 17:03 UTC · Figures derived from the full chain (28.5K contracts, 56 expirations) · IV own-history percentile appears after 60 recorded days (3 so far)
Expected move — Sep 30, 2026 (27 days)
Methodology →Read from option prices: the at-the-money straddle costs this much, so the market is pricing a move of about that size in either direction by this date. It is an estimate of movement, not a prediction of direction.
Options are pricing a move of about ±2.5% (range 7,552.01–7,943.91) by Sep 30, 2026. ATM straddle: 195.95 @ strike 7,750 · ATM IV: 11.6%.
Probability distribution
Model & assumptions →The curve shows where a lognormal model, fed with current implied volatility, puts the range of outcomes at this expiration. Shaded: the expected-move band.
| Level | vs price | P(above)Model-estimated chance the stock finishes above a level at expiration, derived from current IV under a lognormal model with stated assumptions — an estimate, not a prediction. | P(below) |
|---|---|---|---|
| 6,973.16 | -10% | 100.0% | 0.0% |
| 7,360.56 | -5% | 94.6% | 5.4% |
| 7,747.96 | +0% | 49.4% | 50.6% |
| 8,135.36 | +5% | 6.0% | 94.0% |
| 8,522.76 | +10% | 0.1% | 99.9% |
Model-estimated probabilities of finishing above/below each level at expiration — estimates under stated assumptions, not predictions.
Probability explorer
Drag the slider to any level and see the model-estimated chance the stock finishes above or below it at the selected expiration.
Horizon: Sep 30, 2026 · lognormal model, zero drift — an estimate, not a prediction. Assumptions
Expirations
Open the chain →| Expires | DTEDays to expiration, in calendar days. | Implied move | ATM IV | Open int. |
|---|---|---|---|---|
| Sep 03, 2026 | 0 | ±0.2% | 11.9% | 318.2K |
| Sep 04, 2026 | 1 | ±0.5% | 12.0% | 678.8K |
| Sep 08, 2026 | 5 | ±0.7% | 7.9% | 173.4K |
| Sep 09, 2026 | 6 | ±0.9% | 8.6% | 117.7K |
| Sep 10, 2026 | 7 | ±1.0% | 9.2% | 74.5K |
| Sep 11, 2026 | 8 | ±1.2% | 10.3% | 356.3K |
| Sep 14, 2026 | 11 | ±1.3% | 9.6% | 75.5K |
| Sep 15, 2026 | 12 | ±1.4% | 9.9% | 52.1K |
| Sep 16, 2026 | 13 | ±1.6% | 10.8% | 52.4K |
| Sep 17, 2026 | 14 | ±1.7% | 11.2% | 33.2K |
| Sep 18, 2026 | 15 | ±1.9% | 11.4% | 688.6K |
| Sep 21, 2026 | 18 | ±2.0% | 11.0% | 33.0K |
Open interest by strike — Sep 30
Where option positions are concentrated. Teal bars are calls, red bars are puts; the dashed line is the current price.
Largest open-interest concentrations (all expirations ≤ 60 days): 6,300 P · 183.0K6,000 P · 168.3K6,400 P · 135.7K6,350 P · 134.9K6,250 P · 125.5K
IV term structure
Volatility page →At-the-money implied volatility for each expiration. A hump around a date often marks a scheduled event the market is pricing.
When does open interest expire?
Implied vs realized volatility
HV from our stored daily closes (annualized); IV30 interpolated from the chain. Method
Price, last 60 sessions
Track record
Full history →Of 3 recorded snapshot-versus-outcome comparisons so far, the close landed inside the expected range 66.7% of the time.