An option to buy or sell index CDS protection. Follow payer and receiver directions, a clean spread example, and the default and delivery terms it leaves out.
Credit index option
A credit index option gives its holder the right, without the obligation, to enter a specified credit default swap index position at an agreed strike. It makes broad credit exposure conditional: a bond portfolio manager can buy the right to obtain index protection if credit conditions deteriorate, while retaining the choice to let the option expire. The premium pays for that choice.
This is an option on an index CDS contract, such as a specified CDX or iTraxx series, rather than an option on a stock-market index. The series, version and underlying CDS maturity matter alongside the option's own expiry.
Payer means buying protection
A payer option gives its holder the right to become a credit protection buyer. A receiver option gives the right to become a protection seller. Both can be bought options; “receiver” does not mean the person who sold the option.
For a spread quotation, a payer generally benefits from widening spreads, other things equal: the right to buy protection at a previously agreed level becomes more attractive when protection becomes expensive. A receiver generally benefits from tightening spreads. Buying a payer therefore takes the opposite credit direction from owning a risky bond, which usually loses value when its credit spread widens. ISDA's CDS swaption discussion sets out these directions and the protection positions created on exercise.
The quotation also matters. With a spread strike, the payer's favourable direction is up in spread. With a clean-price strike, its favourable direction is down in index price. A price quotation represents the index CDS economics under its coupon convention; it is not the option premium. The index provider's CDS Indices Primer, §5, shows the reversed price and spread moneyness comparisons. Translate the quote before calling a payer a “call” or a “put.”
The delivered index CDS can have a fixed running coupon even when the option strike is quoted as a spread. Converting that strike into an upfront amount reconciles the strike economics with the coupon. The option premium, this exercise-related upfront amount and subsequent CDS coupons are three different payments.
A deliberately clean expiry calculation
Consider a fictional payer option with these stipulated inputs:
Input
Assumption
Notional N
USD 1,000,000
Spread strike K
100 basis points per year
Spread sT at option expiry for the remaining CDS term
140 basis points per year
Risky annuity AT, held fixed
4 years
Credit events before expiry
None
A risky annuity converts an annual CDS spread into value per unit notional through discounted, credit-weighted premium accruals. Four years here is a stipulated valuation multiplier, not a guarantee that four annual payments will occur.
Under a fixed-annuity clean exercise-value approximation, the payer and receiver values are
ETpayer≈NAT(sT−K)+,ETreceiver≈NAT(K−sT)+,
where x+=max(x,0) and annual spreads are written as decimals. For the payer,
1,000,000×4×(0.014−0.010)=USD 16,000.
The receiver's clean exercise value in this same scenario is zero. One basis point is 0.0001 per year, so each basis point beyond the strike contributes USD 400 in this fixed-annuity picture. The 40-basis-point difference produces USD 16,000; using “40” directly as the decimal spread would introduce a factor-of-10,000 error.
Fictional fixed-annuity exercise values: payer rises above a 100 bp strike and reaches USD 16,000 at 140 bp; receiver rises below 100 bp. Notional is USD 1 million, risky annuity 4 years, with no pre-expiry defaults and premium excluded.
Fictional no-default expiry example. Solid payer and dashed receiver curves use the same fixed four-year risky annuity. The chart shows clean exercise value, excluding the option premium and contractual settlement adjustments.
This USD 16,000 is neither the price paid for the option today nor a fully specified index-option settlement payment. No distribution of future spreads, discounting to today or premium has been supplied. Nor is it net trading profit. Holding the annuity fixed deliberately removes its sensitivity to spreads, survival and the remaining payment schedule.
The part a spread-only picture leaves out
A credit event can occur between buying the option and exercising it. Front-end protection concerns losses over that pre-expiry interval when the option terms include them. Looking only at the spread of surviving index names can then omit part of the economics. This feature does not by itself promise an immediate cash payment when a constituent defaults.
An index option need not disappear when one constituent defaults. ISDA describes index-swaption terms that, on exercise, incorporate credit-event obligations from the period since the option was entered. It contrasts these with typical single-name swaptions that terminate following a pre-exercise credit event. The relevant dates and any knockout are contractual; a constituent default is not a universal index-option cancellation rule. ISDA, pp. 39–40.
For a concrete cleared implementation, ICE Clear Credit offers European-style index options with physical delivery. Here physical delivery means creating the underlying index CDS position. It does not mean delivering a portfolio of bonds at option expiry, and cash payments can accompany the delivered position.
ICE's settlement-payment guide distinguishes expiry before or on auction settlement from expiry after it. Its calculation accounts for the strike, the delivered index version, index factor, coupon accrual and credit-event adjustments. After auction settlement, the delivered surviving index position is accompanied by the relevant auction-loss payment, with accrual treatment reflecting the defaulted names. Thus the index factor, which scales the remaining index notional, and realised default losses are separate inputs. Multiplying the simple spread payoff by a smaller factor does not reconstruct all those cash flows. The guide also identifies differences in bilateral accrual practices.
Consequently, the option confirmation and applicable clearing terms must specify exercise procedures, delivery and any cash-settlement alternative, quote conversion and pre-expiry credit-event treatment. There is no single spread-only formula that settles every credit index option.
Pricing the choice requires another layer
A spread scenario tells us how the right responds in that scenario. An option premium additionally depends on uncertainty before expiry. Spread volatility measures variation in spreads; it is not a probability of default. A valuation model must connect its spread or price dynamics with the annuity, recovery assumptions and any default-loss adjustments required by the contract.
The reduced-form credit-risk lesson develops survival-weighted premium and protection legs, explaining the valuation ingredients behind an annuity and a par spread. Its public preview is open; full teaching requires membership. The Options primer, available with free sign-in, develops the separate distinction between exercise payoff, premium and profit. Neither calculation by itself supplies the full index-option contract model.
