CDX and Credit Default Swaps
CDX and Credit Default Swaps
A credit default swap (CDS) is an insurance contract against default. Buyer pays an annual premium (the CDS spread). Seller covers losses if default occurs. Unlike bonds, where you're trading duration and credit and liquidity bundled together, a CDS isolates pure default risk. The CDS spread is the market's direct measure of default probability, separated from bond-specific factors.
Key takeaways
- CDS spreads are pure default probability pricing, uncontaminated by duration or liquidity effects
- A 200 basis point CDS spread implies roughly 2-3 percent annual default probability
- CDX indices track average CDS spreads for groups of issuers (e.g., investment-grade, high-yield)
- CDS and bond spreads diverge when credit deteriorates or credit concerns spike
- CDS pricing often leads bond repricing, providing early-warning signals
CDS mechanics: the insurance analogy
You hold $1 million of bonds issued by TeleCorp. Default risk concerns you. You purchase a CDS from a bank (the CDS seller). The terms:
- Premium (spread): You pay 200 basis points annually. On $1 million, that's $20,000 per year.
- Protection: If TeleCorp defaults before the maturity date, the CDS seller pays you par value ($1 million). You're restored to par even if bonds trade at 40 cents on the dollar.
- Duration: CDS typically have 5-year terms. You can buy 1-year, 3-year, 10-year CDS, depending on exposure.
The 200 basis point spread is the insurance premium. It reflects the seller's assessment of default risk. If default probability is 2 percent annually and recovery is 40 percent (so loss-given-default is 60 percent), the expected payout is 1.2 percent annually (2 percent × 60 percent). The seller charges 200 basis points, earning roughly 80 basis points of profit per year (the spread above expected loss).
In reality, spreads are higher than actuarial expected loss because sellers demand risk premium. A 200 basis point spread on a 2 percent annual default probability bond includes roughly 80 basis points of pure risk premium.
CDS vs. bond spreads: the basis
The "basis" is the difference between bond spreads and CDS spreads. Typically, bond spreads are wider because bonds include liquidity premium and option value (downgrade risk). A bond trading at 180 basis points might have a CDS spread of 140 basis points. The 40 basis point positive basis reflects liquidity and downgrade optionality in the bond, not in the CDS.
This basis relationship breaks down during stress. In 2008, when default fears spiked, CDS spreads often exceeding bond spreads. Bond holders wanted to get out desperately and couldn't, so they bid lower on bonds. CDS buyers were more willing to pay for insurance. CDS spreads blew out past bond spreads, inverting the normal basis relationship.
The basis inversion signaled panic. When basis inverts and stays inverted for weeks, it means the market is fundamentally reassessing credit. Bond holders are selling at any price, and CDS buyers are overpaying for protection.
CDX indices: average CDS pricing across cohorts
Individual CDS spreads are hard to track — there are thousands of issuers. CDX indices aggregate CDS spreads across groups:
- CDX IG: Investment-grade CDS, 125 issuers tracked, representing the median BBB- company
- CDX HY: High-yield CDS, 100 issuers, representing the median B company
- iTraxx: European equivalent of CDX, with IG and HY variants
The CDX IG index itself has a quoted spread. If CDX IG trades at 120 basis points, it means the average annual premium to insure against investment-grade default over 5 years is 120 basis points. This is a real-time, continuously-traded price.
These indices are benchmarks. Portfolio managers track CDX levels to gauge risk appetite and credit stress. When CDX IG rises from 80 to 150 basis points, it signals credit deterioration. When it falls from 150 to 80, it signals credit improvement.
CDS as early-warning system
CDS spreads often move ahead of bond prices and agency ratings. Here's why:
CDS is a pure credit bet. A CDS trader is betting purely on default, uncontaminated by duration or liquidity. When credit stress appears, a CDS trader can immediately increase exposure by buying CDS spreads. A bond trader, facing liquidity constraints and bid-ask costs, might wait or move more slowly.
Additionally, CDS trading is more leveraged. A CDS seller earning 200 basis points premium on $100 million notional is earning $200,000 annually on a small upfront capital requirement. The leverage allows larger positions on smaller capital. Traders can move the market faster.
During the 2019 Constellation Brands earnings miss and warning (beer and spirits producer), CDS spreads widened by 70 basis points in one day. Bonds widened 40 basis points. The CDS market repriced first and more aggressively. Two weeks later, rating agencies downgraded Constellation. Investors who watched CDS spreads had early warning.
Basis trading and arbitrage between CDS and bonds
When CDS and bond spreads diverge, traders exploit the difference. This is basis trading.
Example: TeleCorp bonds trade at 180 basis points spread. CDS trades at 200 basis points. The basis (bond spread minus CDS spread) is -20 basis points, meaning CDS is expensive relative to bonds.
A basis trader might:
- Buy TeleCorp bonds at 180 basis points
- Sell TeleCorp CDS at 200 basis points
- Pocket the 20 basis point annual profit if the positions are held to convergence
If the basis normalized to zero (bond spreads and CDS spreads equal), the trader profits. This forces convergence — basis traders' buying of bonds and selling of CDS tightens the spread differential.
In normal markets, basis is small (5-30 basis points) and exploited quickly by banks and hedge funds. In stressed markets, basis widens dramatically as liquidity evaporates and CDS sellers withdraw. During the COVID crash of March 2020, basis on investment-grade bonds blew out to 100+ basis points, meaning CDS were trading far above bonds as sellers demanded massive premiums to protect against default.
Pricing default probability from CDS spreads
CDS spreads can be converted directly to implied default probabilities using simple formulas.
For a 5-year CDS with 40 percent recovery:
Implied Annual Default Probability = (CDS Spread × 100) / (100 × (100 - Recovery Rate %))
With a 200 basis point (2 percent) CDS spread and 40 percent recovery:
Implied Annual Default Probability = 200 / (100 × 60) = 3.33 percent
This means the CDS market is implying roughly 3.3 percent annual default probability. Over 5 years, cumulative probability would be roughly 15 percent (simplified, without compounding).
A company with 15 percent 5-year cumulative default probability is solidly BB-rated territory. If that company is rated BBB by Moody's, the CDS market is saying the rating is too generous.
This calculation is illustrative. Actual CDS pricing includes risk premium, liquidity premium, and correlation effects. But it shows how CDS can be translated to default probability.
CDS spreads in portfolio hedging
Institutional investors use CDS to hedge credit exposure. A pension fund holding $50 million of corporate bonds might buy $50 million notional of CDS to fully hedge default risk.
The cost is the CDS spread. If spreads are 150 basis points, the cost is $75,000 annually. If spreads are 50 basis points, the cost is $25,000 annually.
This creates a natural hedge decision point. When CDS spreads are expensive (300+ basis points), hedging costs a lot, and many investors choose to accept unhedged risk. When spreads are cheap (50 basis points), hedging is affordable, and many buy protection. This buying during cheap periods and selling during expensive periods provides a natural price anchor.
Market-implied default forecasting
Next
CDS spreads provide a direct window into market-implied default probability. But they're instruments available primarily to institutional investors and sophisticated traders. The general market for credit risk also includes high-yield bonds and credit-focused mutual funds. The next article examines private credit and unrated debt — the growing market of credit that bypasses rating agencies entirely.