Estimating SPY Expected-Move Bands from VIX and VWAP

Summary

This indicator estimates price bands around daily or weekly VWAP using implied volatility as a proxy for expected movement. For SPY, it uses VIX as the volatility input; it also maps several individual-stock volatility indexes and allows a configurable volatility source when data is unavailable. The calculation converts the volatility reading into a one-standard-deviation move using a 30-day horizon scaled to a daily amount, then plots multiple bands above and below VWAP, including optional half-step levels.

The document presents the bands as a visualization of options-implied expectations, not as observed future outcomes or guaranteed price limits. It says the indicator is most meaningful for SPY, though it may be applied to instruments strongly correlated with SPY. The displayed levels are selectively shown near price to reduce chart clutter, and the VWAP period can be changed between day and week. No backtest or evidence on the realized frequency of band touches is provided.

Key ideas

• The indicator derives a daily move estimate from implied volatility and plots deviations around VWAP.
• VIX serves as the default volatility proxy for SPY, while selected stocks can use their own volatility indexes.
• Users can change the VWAP period, volatility source, band styling, and visibility of intermediate levels.
• The bands express an implied estimate and do not guarantee where prices will trade.
• The author identifies SPY as the primary use case and provides no performance validation.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.