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phoenixOmega
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Joined: December 30th, 2007, 6:19 am

Swaption Vol Skew

February 15th, 2009, 12:16 pm

I apologize if this is too basic, but I am struggling with the volatility implied by the swaption skew and local volatility...Take for example we're looking at a 5y10y 200 bps OTM payer and the current ATMF is at 2%. Let's say the implied volatility (on a bpvol basis) backed out from someone's bid price is 80 bp vols. Does this mean that the person buying this swaption believes that when the ATMF is at 2%+200bps = 4%, that the normalized volatility will be 80 bp vols?? If not, how do I transform this implied volatility to reflect where implied volatility will be if the ATMF is at 4%....????
 
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SpeedBall
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Joined: April 30th, 2007, 9:54 am

Swaption Vol Skew

February 16th, 2009, 10:20 am

phoenixOmega,for an ATMF it is correct to assume that x bp norm implied vol means you can expect x bp of vol over the life of an option.But when looking at skew...it tells you the implied vol of Fwd+200 when ATMF = Fwd (local vol...d(vol)/d(moneyness))...when the ATMF becomes equal to Fwd + 200...your local itself will change and the skew will be different again (determined by SABR beta)For details I would recommend reading original SABR paper (Hagan et. al.)