Deep Dive · Swaps · Lesson 5
Credit Default
Swaps
Big Idea
A credit default swap (CDS) works like insurance on a borrower. The protection buyer pays regular premiums to the protection seller; if the reference borrower has a credit event — a default — the seller compensates the buyer for the loss. Unlike other swaps, the CDS buyer pays an ongoing premium, and you do not have to own the borrower’s bond to buy one.
- The buyer pays premiums; the seller pays out only if the borrower defaults.
- It is the one swap with a real premium — and you need not own the bond to buy it.
Think of it as an insurance policy written on someone else’s debt.
Insurance on a Bond
A CDS has two roles, and they map cleanly onto an insurance policy. The buyer of protection pays a periodic premium — often quoted as an annual spread on the amount covered. The seller of protection takes those premiums and, in return, agrees to pay out if the named borrower defaults.
Premiums flow in steadily; a payout happens only if the bad event actually occurs. If the borrower keeps paying its debts, the seller simply pockets the premiums. If the borrower fails, the seller has to make the buyer whole — exactly the bargain an insurer strikes on a house or a car.
A Worked Example
Suppose you buy a CDS on $10,000,000 of a company’s debt, with a premium of 1% per year. That is $100,000 a year you pay to the seller. There are two ways the story ends.
| Outcome | What Happens |
|---|---|
| No default | You keep paying $100,000 a year and receive nothing back — like insurance that went unused. |
| Default | The seller compensates you for the loss. If the bonds are worth about 40 cents on the dollar (a 40% recovery), the loss is about 60% of $10,000,000 — so the seller pays roughly $6,000,000. |
Small, steady premiums out; a large payout only if the borrower fails.
You Do Not Need to Own the Bond
Here is where a CDS parts company with ordinary insurance. You can only insure a house you own — but you can buy a CDS on a borrower whose bonds you do not hold at all. Bought that way, purely as a view that the borrower’s health is deteriorating, it is sometimes called a naked CDS.
That flexibility cuts two ways. A CDS is a genuine hedging tool for someone who owns the bond and wants to protect it — and it is also a way to speculate on credit for someone who simply thinks a borrower will struggle. Both uses are legitimate; it is worth knowing which one you are doing.
The 2008 Story
Credit default swaps on mortgage-backed securities were central to the 2008 financial crisis. The insurer AIG had sold enormous amounts of protection it could not cover, and when defaults hit all at once, it could not pay and had to be rescued. That episode is a big reason post-crisis reforms pushed swaps toward central clearing and collateral — so that a seller’s promise is backed by more than its word.
Interactive Checks
Check 1 of 3
You are explaining the two roles in a credit default swap.
In a credit default swap, what does each side do?
Check 2 of 3
A friend assumes a CDS is only for people who hold the bond.
Do you have to own the borrower’s bond to buy a CDS on it?
Check 3 of 3
You are recalling why CDS mattered so much in 2008.
Why were credit default swaps central to the 2008 crisis?
Common Beginner Mistakes
- ❌ Thinking you must own the bond to buy a CDS. You can buy protection purely as a view on a borrower — a naked CDS.
- ❌ Treating selling protection as easy income. The premiums look free until the tail risk hits — as 2008 showed, the losses can be enormous.
- ❌ Getting the premium direction backwards. It is the buyer of protection who pays the premium, not the seller.
- ❌ Ignoring counterparty risk. The protection is only as good as the seller’s ability to actually pay when a default happens.
Quick Memory Tool
- CDS = insurance on a borrower
- The buyer pays premiums; the seller pays out on default
- The buyer need not own the bond
- Selling protection carries large tail risk (AIG, 2008)
- The protection is only as good as the seller’s ability to pay
Next Lesson
Why Use Swaps? — with the three main types covered, next we pull the uses together: reshaping exposure, hedging interest-rate, currency, and credit risk, and who relies on swaps.