| LOS f: Differentiate between the nominal spread, the zero-volatility spread, and the option-adjusted spread. Which of the following statements regarding the option adjusted spread (OAS) is least accurate? The option adjusted spread: 
 
 
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| A) | is the spread added to the Treasury spot rate curve that the bond would have if it were option-free. |  |  
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| B) | is the spread that accounts for non-option characteristics like credit risk, liquidity risk, and interest rate risk. |  |  
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| C) | for a putable bond is the Z-spread minus the cost of the option. |  |  
 
 
 
Since the buyer of a putable bond must pay extra for the put option, the OAS spread for a putable bond is the Z-spread plus the put option cost in percent.   |