What you will learn
- Separate benchmark-rate and issuer-spread effects.
- Recognize why liquidity and reinvestment remain uncertain.
Credit Spread
A wider spread means the market demands more compensation, which may reflect higher perceived default risk, lower liquidity or a weaker economic outlook; a narrower spread suggests the opposite. Spreads differ by issuer, rating, maturity and sector, and can be measured against different benchmarks.
If the benchmark yield stays unchanged and the spread widens, the bond's yield rises and its price falls. Spread is not the same as expected loss: it also contains a premium for bearing uncertainty and illiquidity, so it cannot be read as a default probability.
Liquidity
Several features signal liquidity: a narrow bid-ask spread, large quantities displayed near the best prices (depth), steady trading volume, and prices that recover quickly after a large order. Liquidity is not constant, since it varies by instrument, time of day and market conditions.
When liquidity is thin, orders of the same size cause larger price moves, spreads widen, and exits can take time or cost more. Stress events can dry up liquidity suddenly even in normally active markets, so volume that looks sufficient in calm periods may not be there when needed.
Correlation
The usual measure, the Pearson coefficient, equals the covariance of two return series divided by the product of their standard deviations. It should be computed on returns, not price levels, because two trending price series can look strongly correlated even when their returns are unrelated.
Correlation depends on the window and data frequency, and it is not stable: relationships estimated in calm periods often strengthen in market stress. It captures only linear co-movement, says nothing about causation, and is not beta, which also depends on relative volatility.
Worked example: A spread can offset a rate decline
Illustrative: a fictional issuer yield is 5%, comprising a 3% reference yield plus a 2 percentage-point credit spread. If the reference falls to 2.5% but the spread widens to 3 points, issuer yield becomes 5.5%. Falling reference rates therefore do not ensure a price gain. Future coupons also need to be reinvested at rates that are not known today.
Check your understanding
A reference yield is 2.8% and an illustrative credit spread is 180 basis points. What is their simple sum?
Show answer and explanation
180 basis points = 1.8 percentage points, giving 4.6%. This spread quotation alone does not quantify the probability or size of default losses.