The spread is a trading cost designed into every quote: the difference between the bid (sell) price and the ask (buy) price, paid implicitly the moment a position opens.

Spreads widen during low-liquidity hours, around major news releases, and at the daily rollover — the same windows where daily-limit breaches cluster. For evaluation traders the spread matters twice: as a per-trade cost that compounds across high-frequency styles, and as a risk factor, because a widened spread can trigger a stop-loss or push floating equity through a limit at a price no chart candle ever printed. Always check whether a program quotes raw spreads plus commission or marked-up spreads with none.