Hi All,I am facing a peculiar problem.Put Call parity is the basic premise of black scholes pricing. Where call plus bond is equal to put plus stock.From which we can derive that when S = K*exp(-rt) then Call price = Put price. So when Strike is equal to Forward Stock price .. call price should be equal to put price.We have implemented Garman Kohlagan for currency option pricing.. and our implementation does not exhibit the above behaviourthe price of ATMF call is marginally higher than that of ATMF put. I find it a bit disturbing but have not been able to pin down a plausible reason. Could somebody please suggest whether this is the observed case or am i making some very obvious stupid mistake.Thanks and Regards,Jugal

What do you think ? Do you think no one has spotted this "arbitrage" in all the years that the GK formula has been around ? Or do you think you are making a stupid mistake ?