Reference Price The reference price is at the top of the table in the Founder’s Notes each day, and is the price of SPX, SPX (previous), SPY, NDX, and QQQ at the time that the SpotGamma data was collected. The reference prices are what were last used for all metrics and models. This means if the prices of these indices have moved away significantly from the reference prices, then the metrics and models may have changed as well. If there have been violent changes in the market since the most recent update, then the location of the reference prices should be taken into account for additional clarity. Related articles SpotGamma Implied 5-Day Move Zero Gamma Combos Volatility Trigger™ Key Delta Strike