Definition
#A Volume-Weighted Average Price computed with an exponential decay keyed to traded volume rather than elapsed time. Past trades lose weight with a half-life of approximately 4 hours of average-volume trading. Session VWAP resets at midnight UTC; EWMA VWAP does not. It accumulates across session boundaries and gives you a reference price at 00:05 UTC that Session VWAP cannot.
Formula & calculation
#Each trade updates the EWMA with a volume-decay factor α:
Calibrated so that after approximately 4 hours of average-pace trading, prior data carries half its original weight. High-volume periods accelerate that decay; low-volume periods slow it.
ewma_vwap = α × trade_price + (1 − α) × ewma_vwap_prevCalibrated so that after approximately 4 hours of average-pace trading, prior data carries half its original weight. High-volume periods accelerate that decay; low-volume periods slow it.
Units & range
$ (same units as current price). Tracks current price closely in active markets. Can diverge during thin trading or after rapid moves that outpace the decay.
Interpretation
#Use it as a cross-session price anchor. Session VWAP is unreliable in the first 30–60 minutes after midnight UTC; EWMA VWAP has no such gap.
A burst of high-volume trading pulls the EWMA toward the new price faster than a quiet move of the same magnitude. A price deviation on thin volume persists longer than one absorbed by heavy volume.
The dollar value is instrument-specific. Filter on Price vs EWMA VWAP (%) or Price vs EWMA VWAP Z-Score instead.
A burst of high-volume trading pulls the EWMA toward the new price faster than a quiet move of the same magnitude. A price deviation on thin volume persists longer than one absorbed by heavy volume.
The dollar value is instrument-specific. Filter on Price vs EWMA VWAP (%) or Price vs EWMA VWAP Z-Score instead.
Practical usage
#Reference context only. Build scanner rules on Price vs EWMA VWAP (%) or Price vs EWMA VWAP Z-Score, not on the raw dollar level.
Common mistakes
#Frequent interpretation traps and misuse patterns to avoid when applying this metric.
- Filtering on the raw dollar value across symbols. Each instrument's EWMA sits at a different price level.
- Confusing it with Session VWAP. Session VWAP resets at midnight UTC; EWMA VWAP accumulates continuously.