Save S&P 500 Excess CAPE Yield
ECY = (1 / CAPE) - US 10-year bond real yield
When the stock price gets too high, return from stocks tends to be lower than return from bonds for the next 10 years. When ECY gets low, stocks might start to decline, as seen in 2008 and 2018.
S&P 500 Excess CAPE Yield (L)2021-052.72 %
S&P 500 (R)2021-05-174,163.29