Definition

Volume

The number of shares that changed hands during an interval. Volume is the weight behind a price move: the same price change means different things on heavy versus thin participation, and averages computed without it treat both alike.

Formula

Volume = shares traded during the interval (sum of trade sizes)

Drivers — what actually moves it

Participation: more traders active in the interval — earnings days and index rebalances concentrate it.
Liquidity structure: float size and where the ticker trades set the baseline level; compare a ticker to its own history, not to other tickers.
Event flow: news, filings, and index events cluster volume — a spike usually has a cause worth finding in the filings.

Where it comes from

Market data construct (not a filing concept). Reported per trade by venues and aggregated by the data source per interval. Share COUNTS in filings (outstanding, float) are different concepts — those are XBRL-tagged.

Sector caveats — where this breaks

Volume across venues is consolidated differently by different sources — cross-source comparisons need the same consolidation basis.

Candlestick OHLC

Educational use only — not investment advice. Figures come from public SEC filings; Echelon teaches you to analyze data, it never recommends buying or selling any security.