Volume is the number of shares (or contracts) traded in a period — the bars along the bottom of most charts. Price tells you where the market went; volume tells you how much conviction was behind it. A move on heavy volume means many participants agreed to trade at those prices; the same move on thin volume can be a few orders pushing an illiquid tape.
How it's read
The classic adage is "volume confirms price": a breakout on rising volume is taken more seriously than one on falling volume, and a spike in volume often marks moments of capitulation or excitement. Volume also matters for a very practical reason — liquidity. A thinly-traded name is expensive to get in and out of, which quietly eats returns (a real cost we model as trading costs).
How we use it — and don't
On your portfolio view we show price and volume side by side, so you can see conviction behind a move at a glance — that's a convenience, not a trade trigger. Our strategies don't fire off volume spikes; they're built on documented return effects (trend, momentum, low-volatility) and account for liquidity through realistic costs. Why we insist on that discipline is in how to read a backtest.
Educational material — not investment advice.