What is a spread?
A spread is the difference between two prices, rates, or yields. In finance it measures how far apart two values are. That simple idea shows up in many places. Knowing which spread you mean is the first step.
Common uses:
- Bid-ask spread: difference between buy and sell prices in a market.
- Yield spread: difference between interest rates or bond yields.
- Credit spread: extra yield investors demand for default risk.
- Option spreads: combined option positions showing price or profit differences.
Each type of spread tells a different story about cost, risk, or market sentiment.
Bid-ask spread
What it is:
- The bid is the highest price a buyer will pay.
- The ask (or offer) is the lowest price a seller will accept.
- The spread equals ask minus bid.
Example:
- Bid = $10.00, Ask = $10.05.
- Spread = $0.05 or 5 cents.
Why it matters:
- It is a measure of liquidity. Tight spreads mean active markets and low transaction cost. Wide spreads mean illiquid markets and higher cost.
- Market makers earn the spread as profit for providing liquidity.
How to view it:
- In percentage: Spread% = (Ask - Bid) / Midpoint * 100
- Midpoint = (Ask + Bid) / 2
Yield spread
What it is:
- The difference between yields on two bonds or interest rates.
- Often used to compare corporate bonds to a government benchmark.
Example:
- 10-year corporate bond yield = 5.5%
- 10-year treasury yield = 3.0%
- Yield spread = 2.5 percentage points or 250 basis points.
Why it matters:
- A wider yield spread often signals higher perceived risk for the corporate bond.
- Changes in yield spreads give clues about economic outlook and investor risk appetite.
Common measures:
- Basis points: 1 basis point = 0.01 percentage point. So 250 basis points = 2.50%.
Credit spread
What it is:
- The extra yield a borrower pays above a benchmark to compensate for credit risk.
- Often shown as corporate yield minus treasury yield for the same maturity.
Why it matters:
- Credit spreads widen when investors fear defaults or economic trouble.
- Spreads tighten when confidence returns.
Use case:
- Banks and analysts monitor credit spreads to assess loan pricing and market stress.
Option and trading spreads
What it is:
- In options, a spread is a position made of two or more options on the same underlying asset. The goal is to limit risk, reduce cost, or bet on a specific price move.
Simple examples:
- Vertical spread: buy and sell options with the same expiration but different strikes.
- Calendar spread: buy and sell options with the same strike but different expirations.
Why traders use them:
- To define risk and reward.
- To pay less than buying a single option.
- To profit from a range-bound market or from volatility changes.
Swap spread and other spreads
Swap spread:
- The difference between a fixed swap rate and a government bond yield of the same maturity.
- Used to measure bank credit and liquidity conditions.
Other spreads:
- Municipal bond spread
- Mortgage spread
- Cross-currency basis spread
All follow the same basic idea: one rate minus another.
How to calculate a spread
Simple formula:
- Spread = Price A - Price B
For yields:
- Spread (in basis points) = (Yield A - Yield B) * 100
Example:
- Yield A = 6.2%
- Yield B = 4.8%
- Spread = 1.4% = 140 basis points
What spreads tell you
Spreads are short summaries of market forces:
- Liquidity: tight spreads mean cheap trading.
- Risk: wide credit spreads mean higher perceived risk.
- Demand and supply: spreads change with market flow and volatility.
- Cost of doing business: bid-ask shows transaction cost directly.
Practical tips
- Check spreads before trading. A wide bid-ask spread can erase your profit quickly.
- Use yield spreads to compare bonds with similar maturities.
- Watch changes, not just levels. A sudden widening often signals trouble.
- For option spreads, know max loss and max gain before entering.
Frequently asked questions
Q: Is a bigger spread always bad? A: Not always. For investors seeking yield, a larger credit spread can mean higher return but also more risk. For traders, larger bid-ask spreads increase cost.
Q: How often do spreads change? A: Continuously in active markets. Spreads move with news, volume, and volatility.
Q: Are spreads taxable? A: Spreads affect returns and thus taxable gains or losses like any trade. Tax rules depend on jurisdiction.
Summary
A spread is a simple but powerful concept. It measures difference in price or yield. Different types of spreads reveal different market facts: liquidity, risk, and cost. Learning to read spreads helps you trade smarter and make clearer investment decisions.