Bid, ask, spread, volume, and liquidity describe how easily an investment can be traded and what execution may cost. Beginners often focus on the last price, but the current quotes and available quantity can matter more when an order reaches the market.
What is the bid price?
The bid is the highest displayed price at which a buyer is currently willing to purchase. If you submit a market sell order, it generally trades against available bids. The best bid can change or disappear before your order executes.
What is the ask price?
The ask, also called the offer, is the lowest displayed price at which a seller is currently willing to sell. A market buy generally trades against available asks. The quoted ask may cover only a limited number of shares or contracts.
What is the bid-ask spread?
The spread is the difference between the best ask and best bid. If the bid is $49.90 and the ask is $50.10, the spread is $0.20. A trader buying at the ask and immediately selling at the unchanged bid would lose $0.20 per unit before commissions or taxes.
Spreads often widen when a security is thinly traded, markets are volatile, important news arrives, or trading occurs outside regular hours. Compare this cost with the charges covered in Brokerage Fees Explained.
What does volume show?
Volume is the amount traded during a period. It can help describe activity, but high historical volume does not guarantee that enough quantity is available now at the displayed price. A daily figure also hides when trading occurred.
Volume should not be read as a directional signal by itself. Every completed trade has both a buyer and a seller.
What is liquidity?
Liquidity is the ability to buy or sell without causing a large price change. A liquid market typically has a narrow spread, frequent transactions, and meaningful quantity available near the current price. An illiquid market may have a wide spread, few quotes, and sharp price movement from a modest order.
Market depth and order size
The best bid and ask show only the first quoted level. Market depth describes quantities available at additional prices. Suppose 50 shares are offered at $10 and the next 200 at $10.25. A market order for 150 shares could fill partly at each price. The resulting average is worse than the first displayed ask.
This difference between the expected and actual execution is commonly called slippage. It can increase during volatility or when an order is large relative to available liquidity.
How order choice changes the trade-off
A market order prioritizes execution but can cross a wide spread or consume several price levels. A limit order restricts the worst acceptable price but may not fill. Neither instruction creates liquidity that is not present.
Why liquidity matters for position sizing
A position can be small relative to an account yet large relative to the market. If exiting would require consuming several levels, the planned stop price may understate the real loss. Incorporate expected spread and slippage into position sizing.
Different products have different structures
Exchange-listed stocks and ETFs display quotes through market systems. Bonds may trade through dealers, and foreign exchange is largely an over-the-counter market where pricing can vary by provider. Learn more in How the Forex Market Works.
Do not assume a broker’s app displays the entire market. Quote delays, data subscriptions, venue access, and internal pricing can affect what you see.
Practical checks before trading
- Compare the current bid and ask, not only the last trade.
- Express the spread in money and as a percentage of price.
- Check recent volume and available quantity near the quote.
- Be cautious around openings, closings, news, and trading halts.
- Avoid assuming an extended-hours quote will persist.
- Use an order size the market can reasonably absorb.
- Review the completed fill price and quantity.
Frequently asked questions
Is high volume the same as high liquidity?
Not always. They are related, but current spreads and available depth also matter. Historical volume cannot guarantee present execution quality.
Who receives the spread?
The economic result depends on how the order is routed and executed. Market makers and other liquidity providers quote prices, while brokers may have different compensation arrangements. Read the broker’s execution disclosures.
Can a spread change after an order is submitted?
Yes. Quotes update continuously, and orders can be cancelled or replaced before yours reaches the venue.
Sources
This article is general education. Market structure and order handling differ across brokers, venues, products, and jurisdictions.