Anchored VWAP vs VWAP
Anchored volume-weighted average price and the session version run the identical calculation. The only difference is where the sum begins — a fixed session boundary in one case, an event you select in the other — and that choice is the whole of the technique.
Anchored volume-weighted average price and the ordinary session version are the same arithmetic. Price times volume, accumulated, divided by accumulated volume. The only thing that differs is where the accumulation starts — and that single choice is what separates them.
What each one is
Session VWAP starts at the session open and resets each day. Everybody watching that instrument sees the same line, because the start is fixed by the exchange rather than by anybody’s judgement. VWAP covers the calculation.
The anchored version starts wherever you put it. A results release, a gap, a swing low, the day a policy changed. Anchored VWAP covers that variant.
Neither is smoothing price. Both are averages weighted by how much traded at each price, which makes them a rough measure of what participants collectively paid since the start point.
Where they differ
Where the sum begins. One resets on a schedule; the other begins at an event. Everything below follows from that.
Who else sees it. The session line is identical on every screen, which makes it partly self-fulfilling — orders cluster at a level a great many people are watching. Your anchor is yours alone, so it carries no crowding effect at all.
How fast it moves. A session line early in the day is set by a handful of bars and moves quickly. An anchor set months ago has accumulated so much volume that a single day barely shifts it.
Where the judgement sits. The session version has none, which is a strength and a limitation. The anchored one is entirely a judgement about which event mattered.
Where they agree
The formula is identical. Neither has a parameter to tune; there is no period, no smoothing constant and no source option. Once the start is fixed the line is determined.
Both weight by volume rather than by time, so a heavy bar moves them more than a quiet one — which is the property that separates either from an ordinary moving average.
And neither contains a stop. Both draw a line and neither says where an idea is wrong. On this site’s shared series the ninetieth percentile bar range is 1.101, and a stop inside that band is noise on either.
Which one to use
Use the session version for intraday work. It is the reference other participants are trading against, and that crowding is a genuine, if modest, effect — the same argument that makes standard pivot points worth more than an unusual variant.
Use the anchored version when a specific event is what matters. A results release, a policy change, the low a move began from. The session boundary is arbitrary in those cases; the event is not.
Use the anchored version for anything held longer than a day, because a line that resets every morning cannot describe a position measured in weeks.
And when you cannot name why you put the anchor there, use the session version. An anchor without a stated event is a line placed where the chart looked right, which is fitting rather than analysis.
Where the anchored version goes wrong
The anchor gets moved until the line works. Nothing stops you, the chart improves visibly each time, and the finished line passes through points you already knew mattered.
And a poor volume feed undermines both. In a fragmented market the reported volume covers part of the trading, so the weighting is partial — which affects the session version too, and is easy to forget because the line looks equally confident either way.
The original data
Of the 24,971 unique videos in research/search-study-corpus.jsonl, 1 compares the two directly in
the title, at 106,773 views. Separately, the anchored version appears in 29 titles at a median of
14,972 across 26 channels, and the session version in 323 at 6,568 across 204. The counts come from
site/rank_compare.py and site/corpus_count.py.
29 videos at 14,972 against 323 at 6,568. A tenth of the coverage and more than twice the audience per video — which is the signature of a variant people seek out after the standard version has not given them what they wanted.
The answer to the question on that chart depends on when you placed the anchor. Set before the move, it is a reference; set afterwards because the fit looked good, it is a line drawn through points already known to matter — and the two are indistinguishable once drawn.
When it fails
The failure is the anchor chosen for its fit, and the resulting chart is genuinely convincing. You try a swing low; the line runs slightly wrong. You try the gap two weeks earlier; now it catches three reactions cleanly. That version gets kept. What has happened is a parameter search over start dates, scored on how well the output matches history — and the line will keep working on the bars it was fitted to and stop working on the ones it was not.
The second failure is an anchor with no stated event. It is a fitted date.
A third is using the session version for a multi-day position. It resets each morning.
A fourth is expecting the anchored line to have crowding behind it. Only yours sees it.
A fifth is taking a stop from either line. Neither contains one.
And a sixth is trusting the weighting on a partial volume feed. It affects both equally.
Related
Anchored VWAP covers the variant and how to place an anchor. VWAP covers the session calculation. And volume-weighted moving average is the neighbouring idea with a fixed lookback instead of a start point.
The anchor is the whole technique and it is also the trap. Placed on a bar I picked because price later respected it, I have drawn a line through a point I already knew mattered. Placed on a results release, before knowing what happens next, it is a genuine reference.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.