I am currently trying to price and option chain for dividend paying stocks (american style exercise). I am able to calculate the Net Present Value (NPV) of dividends until maturity and then apply Black's approximation to compute the value of the call option.
However, when now trying to apply the same procedure to price Put options, I obtain inconsistent results.
My question is: assuming Black's approximation is a good way to price Call options with discrete dividends being paid, how should I proceed to get a similar approximation for the Puts?
In all the great books I only find reference to pricing the calls.
Thank you for your help in advance!