The CDS spread compensates for credit risk above a risk-free rate and is estimated using default probabilities and recovery rates. The value to the protection buyer and the implied default probability are derived from the present value of expected payment streams.
To estimate the credit default swap (CDS) spread, take into account that the risk-free zero curve is flat at 7% per annum with continuous compounding. With a recovery rate of 30% and the default probabilities each year conditional on no earlier default at 3%, the estimated CDS spread would compensate for the credit risk above the risk-free rate. The valuation of the CDS from the protection buyer's standpoint with a CDS spread of 150 basis points involves discounting the expected loss and premium payments.
For a binary CDS, where the payoff is all or nothing, the credit spread would be adjusted to reflect this different structure. If the spread were 100 basis points, then by equating the expected loss to the premium, we could back out the implied probability of default.
To determine the value of the swap to the protection buyer and the implied default probability, the present value of payment streams is calculated considering default probabilities, recovery rates, and the given CDS spread.