Lecture 9

Credit default swaps (CDS)

Mechanics

This week we turn to the next section of the course covering credit default swaps, interest rate swaps (along with FRN), and currency swaps. All these instruments are negotiated and originated OTC and dominate global financial markets on most measures of market size and activity. This week we cover credit default swaps (CDS) and the material will be very useful for your Team Project on Bill Ackman and Pershing Square.

CDS, whole new asset class

A credit default swap (CDS) is like an insurance contract in which:

Why is it called a swap?

Typically defined for 5 years

The CDS can be single-name or multi-name:

Reference events specified in a CDS include, but are not limited to:

Remark An intuitive way to think about reference events is they could potentially be anything that materially changes the ability of the reference entity to meet its original obligations of the reference assets, and which therefore would materially or significantly reduce the market value of the reference assets.

The idea of a reference event leading to a significant decline in the market value V of the reference entity’s reference assets leads to:

Payout

The payout upon the occurrence of a reference event is defined as:

Remark Most CDS are cash settled. Also, in the theoretical treatment of pricing and hedging/speculating with CDS, there is no difference between a CDS being cash settled or physically delivered.

We define the important concept of the recovery rate R:

V=RFV = RF

CDS payout=(1R)F\text{CDS payout} = (1 − R)F

Remark This payout (1R)F(1 − R)F is sometimes called the loss given default since it’s how much we’d lose on a holding of the reference asset.

The above illustrates one way in which CDS are used for hedging:

The regular, fixed “insurance premium” paid by the protection buyer to the protection seller is called the CDS coupon or spread or premium.

premium=kFd\text{premium} = kFd

with d=1/2d = 1/2 if semiannual premiums, d=1/4d = 1/4 if quarterly premiums, etc. The market convention is premiums are usually paid quarterly.

Question: Why is k called the CDS “spread”?

Why is it called a spread?

Answer: Let rr be the risk-free rate, or a reference rate such as Term SOFR or Euribor which are effectively risk-free rates. Also let yy be the yield on the reference entity’s reference asset.

Furthermore, we will indeed show that the CDS spread kk reflects the perceived credit risk of the reference entity’s reference asset:

So CDS spreads kk reflect the market’s assessment of the credit or default risk of the reference entity.

Pricing

We now turn to CDS pricing which involves determining the fair or theoretical CDS spread kk. The general principal is:

The CDS spread kk is set so that the CDS has 0 initial value to both the protection buyer and seller (like futures and forwards) so no initial exchange of money takes place at origination.

Here kk is called the breakeven CDS spread. However, note that after the GFC, even though CDS are originated and traded OTC, their terms and specifications have been standardised, and in particular CDS indices are originated with a fi xed CDS spread k and an initial exchange of money usually occurs between buyer and seller (as per the Team Project).

So far we have the following CDS notation and terminology:

For simplicity, we assume that the payout occurs at the end of the premium period in which a reference event occurs.


Example

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Risk-neutral law of finance : The price of a derivative security, including a CDS, is the present value of its (risk-neutral) expected future cashflows discounted at the risk-free rate.

From the perspective of the protection buyer:

So the value of a CDS to the protection buyer is

CDS value = PV( E [payouts]) − PV( E [premiums])\text{CDS value = PV( E [payouts]) − PV( E [premiums])}

PV of expected payouts: At time tit_i there is a payout of:

Hence, the expected payout at time tit_i is

E[payouti]=qi(1R)F\mathbb{E}[payout_i]=q_i(1-R)F

and the present value of all of the expected payouts is

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PV of expected premiums: At time tit_i there is a premium of:

E[premiumi]=sikFd\mathbb{E}[premium_i]= s_ikFd

and the present value of all of the expected premiums is

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The breakeven CDS spread k that which gives the CDS 0 initial value:

PV(E[payouts])=PV(E[premiums]),PV( E [payouts]) = PV( E [premiums]),

which we rearrange to get

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We now give an example showing how the calculate the CDS spread k.


Example cont.

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Pricing cont

We now present an example of CDS pricing in which the CDS spread is set to k = 1% (100 basis points), a common market convention. We calculate the upfront cashfl ow needed between the protection buyer and seller at the initiation of the CDS. I’ll use the same fi gures as above.


Example

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Speculation and hedging

We already mentioned an example of hedging with CDS:


Example

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So the point of this example is:

Remark

Now possibly revisit Michael Burry’s GFC CDS trade, in which he purchased CDS on mortgage backed bonds. “On May 19, 2005, Mike Burry did his fi rst subprime-mortgage deals. He bought $ 60 million of credit-default swaps from Deutsche Bank— $ 10 million each on six diff erent bonds.” The rest is history and was made into the movie The Big Short, and here’s the scene of Michael Burry negotiating to purchase CDS of various banks.

CDS spreads and risk premiums

We now provide a simple, intuitive argument for why the CDS spread k on the reference asset of a reference entity should approximately equal the reference entity’s risk premium over the risk-free rate r. Suppose you:

Then your “net YTM” is the reference asset’s YTM y you receive minus the CDS spread k you pay. Consider the two possible scenarios:

CDS Indices

We now turn to CDS indices, which are useful for your Team Project.

A CDS index such as those in the CDX or iTraxx families are tradable baskets of single-name CDS. They have specifi c rules/features:

An important aspect of CDS indices is how payouts occur:


Example

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Of interest to you for the Team Project, Bill Ackman at Pershing Square purchased the CDX NA Investment Grade, CDX NA High Yield and iTraxx Europe CDS indices to hedge his portfolio exposure.

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