Here is a an analysis of inflation-adjusted monthly closing prices for the S&P 500 from 1905 to now with selected price cycle charts and analysis tables included. Price data from ONLINE DATA ROBERT SHILLER.

Log Adjusted Closing Prices (Splits & Dividends) are particularly useful for multi-year periods of analysis.

Cycle Threshold Sensitivity (%) Min Swing values define the minimum percentage price change required to reverse a trend line or plot a new pivot point. It filters out minor market noise by ignoring moves smaller than the chosen threshold. Smaller swing values generate more price cycles than larger values.

This calculator was generated in part by Gemini-3.