Core terms
Anchored VWAP
VWAP calculated from a start point the trader chooses, such as the open, a news time or a prior high, instead of the session start.
The formula is the same as session VWAP; only the starting bar changes. Anchoring at a news release, for example, gives the average price paid by everyone who traded since the news. Different anchors give different lines, and each line answers a different question.
Because the anchor is chosen, it is easy to pick one after the fact that "fits" the chart. To study anchored VWAP, fix the anchoring rule (for example, "the first 1-minute bar after a halt resumes") before looking at outcomes, and count each anchoring rule separately.
What traders should verify
Write the anchoring rule in the plan. Do not compare counts across different anchors as if they were one setup.
Do not conflate
Trader usage; there is no official definition. Anchors chosen after seeing the chart are a form of hindsight.
Primary source
Trader usage: there is no official definition, and platforms and tools may calculate it differently.