Formula & Calculation Mechanism
Positive readings indicate economic releases are exceeding analyst projections, reinforcing economic growth resilience. Negative readings indicate unexpected data misses.
Market Impact on US Equities & S&P 500
Surprise index turning up from negative extremes (<-30) signals economic bottoming and cyclical stock outperformance.
Historical Precedents & Bull/Bear Regimes
Oscillates in multi-month cycles as analysts adjust forecasts to reality.