Definition
The ask is the lowest price a seller is currently willing to accept. When you buy with a market order, you pay the ask.
Example
“The ask was sitting at $12.40 and kept getting hit every time momentum traders bought the breakout.”
Detailed Explanation
Every quote you see has two sides: the bid (what buyers will pay) and the ask (what sellers want). The gap between them is the spread, and it's an immediate cost that comes out of every trade. When you place a market buy order, you're saying "fill me at whatever the ask is right now" — which is why chasing a fast-moving stock with market orders can get expensive quickly.
On Level 2, you can watch the ask stack in real time. A thin ask — just a few hundred shares offered — can evaporate in seconds during a momentum move, causing price to jump rapidly. A heavy ask, sometimes called a "wall," can stall a breakout and act as a magnet that sellers keep defending. Smart traders read the ask side to gauge how much supply is standing between current price and the next level.
The ask also shifts based on broader conditions. In pre-market or after-hours trading, the ask often sits much wider from the bid because liquidity is thin and sellers want compensation for the extra risk of execution. Always check the spread before hitting a market order in low-volume conditions.