What this shows: the TradingView formula SP:SPX ÷ FRED:UNRATE ÷ FRED:UNRATE × ECONOMICS:USIRYY × ECONOMICS:USINTR ÷ usm2, evaluated month by month as typed (left-to-right, × and ÷ have equal precedence): S&P 500 level × inflation YoY (%) × Fed funds rate (%) ÷ unemployment rate (%)² ÷ US M2 money supply ($bn). The result is a dimensionless index — there is no natural unit, so levels are arbitrary and only the shape and relative changes matter. Higher values mean stocks are expensive relative to the macro mix (or unemployment/M2 are low); lower values mean the macro burden is high.

Leg mapping (TradingView → free equivalent):
SP:SPX → S&P 500 monthly close (Robert Shiller's long-run dataset, 1871+, maintained mirror)
FRED:UNRATE → FRED UNRATE (civilian unemployment rate, %)
ECONOMICS:USIRYY → FRED CPIAUCSL year-over-year % change (US inflation rate, all urban consumers)
ECONOMICS:USINTR → FRED FEDFUNDS (effective federal funds rate, %)
usm2 → FRED M2SL (US M2 money supply, seasonally adjusted, $ billions)

Reading the chart: the line is the raw formula output for each month. It spikes in tight-labour-market, high-rate, high-inflation, low-liquidity regimes and collapses when unemployment or money supply grow. Because it is a ratio of a price level to macro aggregates, it drifts over time — zoom in (scroll / shift+drag) to compare episodes on the same scale. Data may be revised.

Data: chart data (JSON) · source series (CSV) · FRED UNRATE · FRED CPIAUCSL · FRED FEDFUNDS · FRED M2SL