Professor Jeremy Siegel (The Wharton School / University of Pennsylvania) has shown that from 1802 to 2021 (220 years), US equities have a real CAGR of 6.9%. In his book Stocks for the Long Run, he demonstrates that this long term annualized growth rate has been remarkably consistent over many decades spanning wars, depressions, booms and busts. It is sometimes refered to as "The Siegel Constant". We call it SCRAGR (Siegel Compound Real Annual Growth Rate).

This website shows where the market currently stands in relation to the long term SCRAGR trendline. This can indicate an overvalued or undervalued market based on the deviation from the long-term trend.