What Is Volume-Weighted Average Price (VWAP)?
Volume-weighted average price is the ratio of the total dollar value traded in a security to the total shares traded over a given window, usually a single trading day. The formula is VWAP = Σ(price × volume) ÷ Σ(volume), computed across every trade in the period. Weighting by volume means prices where heavy trading occurred count for more than prices touched on thin volume.
Because it reflects where the bulk of the day's business actually happened, VWAP serves as the market's consensus price for the session. A stock that closes at $52 but did most of its volume near $50 has a VWAP close to $50, which tells a more complete story than the closing print alone.
How VWAP Is Calculated and Used
Suppose a stock trades 10,000 shares at $20.00, then 30,000 shares at $20.50, and finally 10,000 shares at $21.00. Total dollar volume is $200,000 + $615,000 + $210,000 = $1,025,000 across 50,000 shares, so VWAP is $20.50. Trading platforms compute this continuously intraday, and many traders watch price relative to VWAP as a gauge of buying or selling pressure.
The main institutional application is execution benchmarking. When a portfolio manager hands a large order to a trading desk, the fill is often judged against the day's VWAP, and execution algorithms are built to track it. A VWAP algorithm slices a parent order into small pieces and releases them in proportion to the stock's typical intraday volume curve, which is heaviest near the open and the close, so the order's average price lands close to the benchmark.
Why VWAP Matters
VWAP gives asset managers an objective yardstick for transaction costs. Slippage versus VWAP quantifies how much value execution added or destroyed, and over thousands of orders those basis points compound into meaningful performance. Best-execution obligations also push brokers to document how fills compared with benchmarks like VWAP and arrival price.
The benchmark has limits worth knowing for interviews. Chasing VWAP can be counterproductive for urgent orders, since an algorithm spreading a buy across the day may watch the price run away from it, and a trader who is a large share of the day's volume drags VWAP toward their own fills, flattering the comparison. VWAP is also strictly a backward-looking intraday measure, so it says little about whether the price itself was attractive.
