Definition
Bid-Ask Spread
The difference between the highest price a buyer is willing to pay (bid) and the lowest price a seller is willing to accept (ask) for a security. Narrower spreads indicate higher liquidity and lower transaction costs, while wider spreads suggest lower liquidity and higher trading costs.
A stock has a bid of $49.80 and an ask of $50.00, creating a bid-ask spread of $0.20 (or 0.40% of the price). An investor buying 100 shares with a market order pays $5,000 (100 × $50.00), while simultaneously selling would yield $4,980 (100 × $49.80), resulting in an immediate $20 transaction cost from crossing the spread.
The ask price is always higher than the bid price. Investors buying shares pay the ask price (higher), while selling receives the bid price (lower). Market makers profit from the spread by buying at bid and selling at ask.
How is Bid-Ask Spread tested on the exam?
- Identifying which price (bid or ask) an investor pays when buying or receives when selling
- Calculating the dollar spread and percentage spread for a given security
- Determining the transaction cost impact when crossing the spread
- Recognizing that narrower spreads indicate higher liquidity and lower trading costs
- Understanding that market makers profit from capturing the bid-ask spread
- Comparing spreads between liquid (large-cap stocks) and illiquid (small-cap, bonds) securities
Regulatory limits
Regulatory Limits
| Description | Limit | Notes |
|---|---|---|
| Typical spread for highly liquid large-cap stocks | $0.01-$0.05 (0.01%-0.10%) | Narrow spreads indicate high liquidity and active trading |
| Typical spread for less liquid small-cap stocks | $0.10-$0.50+ (0.5%-2%+) | Wider spreads indicate lower liquidity and higher transaction costs |
| Typical spread for corporate bonds | 0.25%-2%+ of price | Bond markets generally less liquid than equity markets |
ASK is Always hiGHer: Sellers ASK for MORE money than buyers BID to pay. Remember: You Buy at the ASK (pay more) and Sell at the BID (receive less). Market makers profit from the spread by being in the middle.
Practice questions
Test your understanding with the questions below. Pick an answer to reveal the explanation.
Marcus is evaluating two investment options: Stock A (large-cap technology company) with a bid of $98.50 and ask of $98.52, and Stock B (small-cap biotech company) with a bid of $15.00 and ask of $15.40. He plans to invest $10,000 in one of these stocks and may need to liquidate within 6 months. From a transaction cost perspective, which consideration is most relevant?
B is correct. The percentage spread is the critical metric for comparing transaction costs. Stock A has a 0.02% spread ($0.02 / $98.50 = 0.02%), while Stock B has a 2.67% spread ($0.40 / $15.00 = 2.67%). If Marcus buys and later sells Stock B, he would lose approximately 5.34% in round-trip transaction costs (2.67% × 2) just from crossing the spread twice, compared to only 0.04% for Stock A. This makes Stock B significantly more expensive to trade, especially for a short-term investment.
A is incorrect because dollar spread alone does not reflect the true cost impact; percentage spread relative to price is what matters. C is incorrect because transaction costs differ dramatically based on percentage spreads, not investment amount. D is incorrect because even with limit orders, liquidity and spread width matter; wider spreads make it harder to execute limit orders at favorable prices and increase implicit trading costs.
The Series 65 exam tests your ability to evaluate transaction cost impacts on investment returns, particularly for clients with shorter time horizons. Understanding that percentage spreads (not dollar spreads) determine true trading costs is critical for suitability analysis when recommending securities, especially when comparing large-cap versus small-cap investments.
When an investor places a market order to buy shares of stock, which price will they pay?
B is correct. Investors buying shares pay the ask price (also called the offer price), which is the lowest price at which sellers are willing to sell. Conversely, investors selling shares receive the bid price, which is the highest price buyers are willing to pay. This creates the bid-ask spread, with the ask always being higher than the bid.
A is incorrect because the bid price is what investors receive when selling, not what they pay when buying. C is incorrect because market orders execute at the best available price on the appropriate side of the market (bid for sells, ask for buys), not at the midpoint. D is incorrect because the last traded price is historical information and does not determine the execution price for new market orders; the current bid/ask determines execution.
The Series 65 exam tests basic market mechanics, including which price applies to buy versus sell transactions. Understanding that buyers pay the higher ask price and sellers receive the lower bid price is fundamental to explaining transaction costs and market order execution to clients.
A municipal bond is quoted with a bid of $98.75 and an ask of $99.50. An investor purchases $100,000 face value of these bonds and sells them one month later at the same quoted prices. What is the total transaction cost from crossing the bid-ask spread (ignoring commissions)?
C is correct. Calculate the round-trip transaction cost:
1. Spread = Ask - Bid = $99.50 - $98.75 = $0.75 per $100 face value
2. Per-bond spread = $0.75 (bonds are quoted per $100 face)
3. Number of bonds = $100,000 / $100 = 1,000 bonds
4. One-way spread cost = 1,000 × $0.75 = $750
5. Round-trip cost = $750 (buy at ask, sell at bid crosses the spread once, creating a $750 loss)
Actually, let me recalculate: When buying, investor pays ask ($99.50 per $100) = $99,500 total. When selling immediately at bid ($98.75 per $100) = $98,750 total. Loss = $99,500 - $98,750 = $750.
A ($375) incorrectly calculates half the spread. B ($500) uses an incorrect spread calculation. D ($1,500) incorrectly doubles the round-trip cost.
The Series 65 exam includes calculations involving transaction costs from bid-ask spreads. Understanding how to calculate both the dollar spread and its impact on portfolio returns is essential for evaluating trading costs, particularly in less liquid markets like municipal bonds where spreads can be substantial.
All of the following statements about bid-ask spreads are accurate EXCEPT
C is correct (the EXCEPT answer). The bid price is NOT higher than the ask price; it is always LOWER. The ask (offer) price is always higher than the bid price, creating the spread. This statement reverses the fundamental relationship between bid and ask.
A is accurate: Narrow spreads (e.g., $0.01-$0.05 for large-cap stocks) indicate high liquidity, active markets, and low transaction costs, while wide spreads indicate illiquidity. B is accurate: Market makers provide liquidity by simultaneously posting bid and ask prices, profiting from the spread by buying at the lower bid and selling at the higher ask. D is accurate: The bid-ask spread represents an implicit transaction cost that reduces investor returns, especially for frequent traders or short-term investors who cross the spread multiple times.
The Series 65 exam tests your complete understanding of market mechanics and liquidity. Knowing that the ask is always higher than the bid, and understanding why (market makers need compensation for providing liquidity), is fundamental to explaining transaction costs and trading strategies to clients.
An investment adviser is comparing two ETFs for a client who trades frequently. ETF X (large-cap S&P 500 index) has an average bid-ask spread of 0.01%, while ETF Y (emerging markets small-cap) has an average spread of 0.50%. Which of the following statements are accurate?
1. ETF X likely has higher daily trading volume than ETF Y
2. The wider spread for ETF Y compensates market makers for higher inventory risk
3. A client making 10 round-trip trades per year would pay more in spread costs with ETF Y
4. Both ETFs will have identical transaction costs since they are both exchange-traded
B is correct. Statements 1, 2, and 3 are accurate.
Statement 1 is TRUE: ETF X's narrow 0.01% spread indicates high liquidity and active trading, which requires high trading volume. Large-cap S&P 500 ETFs like SPY trade hundreds of millions of shares daily, while emerging markets small-cap ETFs have much lower volume.
Statement 2 is TRUE: Market makers face greater inventory risk (price volatility, difficulty hedging positions) with emerging markets small-cap securities, so they require wider spreads as compensation for providing liquidity in less liquid markets.
Statement 3 is TRUE: Calculate round-trip spread costs: ETF X = 0.01% × 2 × 10 = 0.20% annually, while ETF Y = 0.50% × 2 × 10 = 10.00% annually in spread costs alone. ETF Y costs 50 times more in transaction costs.
Statement 4 is FALSE: Even though both are exchange-traded, their transaction costs differ dramatically due to spread width. Being exchange-traded does not guarantee identical transaction costs; liquidity and spread width vary significantly across ETFs based on underlying holdings.
The Series 65 exam tests your ability to evaluate multiple factors affecting transaction costs and ETF suitability. Understanding that spread width reflects liquidity, compensates market makers for risk, and materially impacts frequent traders is critical for making appropriate investment recommendations, especially when comparing broad-market versus niche or international ETFs.
What concepts relate to Bid-Ask Spread?
This term is part of this cluster :
Where does Bid-Ask Spread appear on the Series 65 exam?
This term is tested in the following Series 65 exam topics: