TL;DR. A credit default swap (CDS) is a contract where the buyer pays a periodic premium to a seller in exchange for a payout if a specific borrower defaults. It is essentially insurance on a bond — except, unlike insurance, you do not have to own the bond to buy it. The CDS market is centrally cleared in the United States, governed globally by the ISDA Credit Derivatives Definitions, and remains one of the most important — and most misunderstood — corners of capital markets.
What a credit default swap actually is
A CDS has two sides:
- The protection buyer pays a regular premium (quarterly, usually) to the seller.
- The protection seller agrees to make the buyer whole if a defined “credit event” happens to a third party — the reference entity.
The reference entity can be a single company (a single-name CDS) or a basket of companies (an index CDS like CDX or iTraxx). The contract specifies the reference obligations (which of the borrower’s bonds count), the notional (the face amount being protected), the maturity (typically five years for the benchmark contract), and the credit events that trigger payout.
The SEC describes a CDS as a contract whose payments are linked to changes in the credit standing of a reference entity. The Federal Reserve’s post-crisis description is similar: a bilateral derivative that transfers the credit risk of a third party from one counterparty to another.
One sentence that resolves most confusion: a CDS is a price of credit risk, expressed in basis points per year, traded in a market that is separate from the bond itself. The bond market and the CDS market usually agree about how risky a borrower is. When they disagree, that is information.
The worked example: 5-year CDS on a corporate name
Suppose Acme Industrial Co. is a real US corporate borrower. You are a portfolio manager holding $10 million of Acme’s 5-year senior unsecured bonds, and you want to hedge default risk for the next five years.
You enter into a 5-year CDS on Acme as the protection buyer with a dealer counterparty:
- Notional: $10,000,000
- Tenor: 5 years, standard March-June-September-December maturity dates
- Quoted spread: 250 basis points (2.50%) per year
- Premium: $250,000 per year, paid in roughly equal quarterly accruals of about $62,500
- Recovery assumption: 40% (the standard ISDA assumption for senior unsecured corporate debt)
While Acme is solvent, you just keep paying the premium. If Acme suffers a credit event before maturity, the contract triggers. Settlement is now almost always done through cash auction (more on that below), and the payout is roughly:
Payout ≈ Notional × (1 − Final auction price)
If Acme’s senior bonds clear the auction at 30 cents on the dollar, your payout is about $10,000,000 × (1 − 0.30) = $7,000,000, less any accrued premium you still owe. You combine that with the recovery value of the bonds themselves to get back roughly the par amount you started with. That is the hedge working.
The math: where the 250bps comes from
A rough mental model for CDS pricing is the simple credit-triangle equation taught in fixed-income textbooks:
Spread ≈ Probability of default per year × (1 − Recovery rate)
At a 250bps spread and a 40% recovery assumption, the implied annual default probability is about 250 / (1 − 0.40) = roughly 4.2% per year. That is the market’s view, not a forecast.
Standardized contracts often trade with a fixed coupon (100bps for investment grade, 500bps for high yield in the US market). The economic spread is reconciled by an upfront payment — positive or negative — so the present value of the running coupon plus the upfront equals the present value of expected default losses. The CDS Standard Model published by ISDA is the public reference for converting between quoted spread and upfront.
Single-name CDS vs. index CDS (CDX and iTraxx)
Most CDS trading volume today is in indices, not single-name contracts. The benchmarks are:
- CDX IG — 125 investment-grade North American names, equal-weighted.
- CDX HY — 100 high-yield North American names.
- iTraxx Europe Main — 125 European investment-grade names.
- iTraxx Crossover — 75 European sub-investment-grade names.
Each index is rolled to a new “series” every six months — on March 20 and September 20 — with names that fall out of eligibility replaced. The index spread is a single number that summarizes the credit market’s mood the way the VIX summarizes equity volatility.
Credit events: what actually triggers payout
Under the 2014 ISDA Credit Derivatives Definitions, the standard credit events for a corporate CDS are:
- Bankruptcy — a formal filing for insolvency or court-supervised reorganization.
- Failure to pay — a missed scheduled payment on a qualifying obligation above the payment threshold, after any grace period.
- Restructuring — a change to the terms of debt that hurts creditors (e.g., maturity extension, principal reduction, currency change). Restructuring is included in European and Asian contracts; for US single-name CDS, the market standard is “No Restructuring,” meaning restructurings do not trigger.
- Governmental Intervention — added in 2014, captures bail-in events on financial institutions where authorities write down or convert debt.
For sovereign reference entities, the menu also includes repudiation/moratorium and obligation acceleration.
The decision about whether a credit event has actually occurred is not made by either counterparty. It is made by an ISDA Credit Derivatives Determinations Committee, a panel of dealers and buy-side firms covering each region. A binding DC determination affects every contract on that reference entity.
Settlement: the ISDA auction
Once a credit event is declared, settlement was historically “physical” — the buyer delivered the defaulted bond and received par. That worked when CDS notional was small relative to the bond market. By 2008, on names like Lehman or Fannie Mae, the CDS notional was a multiple of the deliverable bonds. Forcing physical settlement would have created a short squeeze on the bonds.
The market response, codified by ISDA after 2009, was a standardized cash auction:
- Major dealers submit two-sided markets on the cheapest-to-deliver bond.
- Initial bids/offers and open interest are published.
- A second round of Dutch-style bidding establishes a single clearing price.
- Every CDS contract pays out at (1 − auction price) × notional.
Below are some of the more widely-cited auction outcomes from historical credit events. These are the final auction recovery prices — the lower the price, the bigger the CDS payout.
| Reference entity | Year | Final auction price | Implied CDS payout |
|---|---|---|---|
| Lehman Brothers (senior) | 2008 | 8.625 | 91.4 cents per $1 |
| Washington Mutual (senior) | 2008 | 57.0 | 43.0 cents per $1 |
| Fannie Mae (senior) | 2008 | 91.51 | 8.5 cents per $1 |
| Hellenic Republic (Greece) | 2012 | 21.75 | 78.25 cents per $1 |
How CDS premium flows actually move
The mental model is easier with a picture. The diagram below shows the two cash-flow legs of a CDS over its life: the buyer pays the premium leg until either maturity or a credit event; the seller pays the protection leg only if a credit event occurs.
The market today: smaller, cleaner, mostly indexed
The CDS market peaked in size before the global financial crisis. The BIS semi-annual OTC derivatives statistics show that CDS notional outstanding, which exceeded $50 trillion at its 2007 peak, has trended below $10 trillion in the post-crisis era as standardization, mandatory clearing, and portfolio compression squeezed out duplicative offsetting trades. Volumes have shifted from single-name contracts to indices, and the bulk of dealer-to-dealer CDS is cleared at ICE Clear Credit or LCH’s CDSClear.
The chart below shows the rough shape of the contraction — CDS notional outstanding from its pre-crisis peak through the post-crisis steady state.
Common mistakes and where CDS misleads
- “Buying CDS is buying insurance.” Sort of. The economics rhyme, but you do not need an insurable interest, the counterparty is a dealer rather than an insurer, and the contract is governed by ISDA, not insurance law.
- “CDS spreads equal default probability.” No. Spreads embed default probability and assumed recovery and a risk premium for taking that risk. The textbook formula above is a first approximation, not a forecast.
- “If a name blows up, CDS pays par.” Only if the auction clears at zero. In practice, most senior corporate auctions clear between 30 and 70 cents.
- “Bond spreads and CDS spreads must equal.” The CDS-bond basis is rarely exactly zero. Funding cost differences, repo specialness, and balance-sheet limits on dealers all push it around.
- “Index CDS and the underlying single-name basket must equal.” The CDX skew — the gap between the index and its constituents — is a real trade, not a pricing error.
The 2008 lesson: AIG Financial Products
The single most important episode in CDS history is AIG Financial Products. According to the Financial Crisis Inquiry Commission and contemporary disclosures, AIGFP had written credit default swaps insuring roughly $441 billion of securities originally rated AAA, including about $57.8 billion of super-senior tranches backed by subprime mortgages. As collateral was reclaimed and the underlying mortgage CDOs were downgraded, AIG faced enormous mark-to-market collateral calls it could not meet.
On September 16, 2008, the Federal Reserve announced an initial $85 billion secured credit facility to AIG; the support package eventually grew to roughly $182 billion in commitments. As the Treasury’s TARP page on AIG documents, the government ultimately recouped its assistance.
What the AIG story actually shows is not that CDS is uniquely dangerous — it shows that a single counterparty taking concentrated, unhedged credit-correlation risk on opaque structured products without posting daily collateral can become systemic. The post-crisis fixes — central clearing, standardized contracts, daily variation margin, public position reporting via the DTCC repository — were designed precisely so a 2008-style blow-up cannot happen the same way again.
Related concepts and what to read next
- Investment Grade vs High Yield Bonds — CDS spreads sort credits along the same continuum as bond ratings.
- Bond Duration — CDS isolates credit risk from interest-rate risk; duration is the other half.
- Bond Convexity — nonlinearities matter for bonds the same way they matter for CDS valuation at low recovery.
- Repo and Reverse Repo — CDS-bond basis trades are funded in repo, which is why funding stress moves the basis.
Sources
- ISDA — 2014 Credit Derivatives Definitions: the master legal framework for standardized CDS contracts.
- SEC Investor.gov glossary — Credit Default Swap: regulator’s plain-English definition.
- BIS semi-annual OTC derivatives statistics: official source for CDS notional outstanding.
- ICE Clear Credit: the dominant central counterparty for cleared CDS in the US market.
- creditfixings.com: published auction results for major credit events.
- US Treasury — TARP AIG page: government accounting of the 2008 AIG support.
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.