An equity curve is a chart of an account’s value over time, plotted trade by trade or day by day, showing how a strategy’s results accumulate. It is the single most information-dense picture of a trading system: slope shows profitability, smoothness shows consistency, and the dips show drawdowns.
Two strategies with identical total returns can have radically different curves — one a steady climb, the other a flat year rescued by two outlier wins. The second is far harder to trade and far more likely to be luck. Reading the curve alongside trade count and expectancy is how you separate a durable edge from a good run.
Equity curves are standard output in any serious backtest and worth maintaining for live results too, because a live curve that departs sharply from the backtested one is the earliest warning that conditions have changed or the edge was overfit.