Ask

### The price you actually pay Investor.gov's definition is blunt: the ask is the lowest price at which a seller will sell. Your market buy takes it. Everything interesting about the ask happens when the size you want is bigger than the size offered there, or when that offer vanishes before your order arrives. ### Why slippage lives here The SEC's [Investor Bulletin on order types](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins-14) states plainly that the price at which a market order will be executed is not guaranteed, and that in fast markets the fill often deviates from the last-traded price or the real-time quote. FINRA adds that a market order generally executes at or near the current bid or ask during normal hours, 9:30 a.m. to 4 p.m. Eastern, and that in highly volatile markets millions of shares can trade in microseconds. Read those together and slippage stops looking like a broker trick. It is two ordinary things: the ask moving between the moment you look and the moment your order lands, and your own order eating up through the offers stacked above the best one. ### When the ask runs Brokers document the conditions openly. OANDA's spreads and margin page lists the opening and closing of markets, major geopolitical events, natural disasters and severe weather among the conditions where spreads expand beyond normal levels. A wider spread means the ask has stepped away from the bid, and a market buy pays that widening in full. - Around a news release, the ask can print far above the bid you were watching a second earlier. - At a session open there are fewer resting offers, so the same order walks further up the book. - In a thin instrument the spread is permanently wide, so the cost is structural, not occasional. ### The choice most beginners never realise they made A limit order caps the damage: FINRA notes a buy limit order can be executed only at or below the limit price. The trade-off is honest, and the SEC says it out loud: a limit order is not guaranteed to execute at all. Market orders buy certainty of fill and pay for it with uncertainty of price. Limit orders do the exact reverse. Knowing which of the two prices your order hits, and which of those two risks you just accepted, is what separates a controlled entry from a surprise.