Definition
Option-Adjusted Spread measures a bond's yield spread over the Treasury curve after removing the value of embedded options (calls, puts). It allows fair comparison between bonds with and without options. OAS is calculated using option pricing models and represents the spread investors receive for credit and liquidity risk alone.
Formula
OAS = Z利差 - 期权成本（以利差表示）
Example
A callable bond yields 5.5% vs. 4% Treasuries (150bp nominal spread). Adjusting for call option, OAS is 110bp.
FAQ
What is OAS (Option-Adjusted Spread)?
A bond's spread over Treasuries adjusted for embedded options.
How do you calculate OAS (Option-Adjusted Spread)?
A common formula for OAS (Option-Adjusted Spread) is: OAS = Z利差 - 期权成本（以利差表示）
Why is OAS (Option-Adjusted Spread) important?
OAS (Option-Adjusted Spread) helps investors evaluate fixed income and make more informed decisions.