What Is Ask?
The ask (or offer) is the lowest price at which a seller is willing to part with an asset. On an order book, the ask side represents sell orders stacked from lowest to highest price. The best ask is the most competitive sell price available at any given moment.
How Ask Works
When a buyer places a market order, it executes against the best ask. The difference between the best bid and best ask is the spread. In liquid markets, the spread is tight (often a fraction of a percent), while illiquid markets have wider spreads that increase trading costs.
Why It Matters for Traders
Understanding the ask side of the order book reveals selling pressure. A thick wall of asks at a specific price level can act as resistance. Watching the ask depth relative to bid depth gives traders insight into short-term directional bias before price moves.