Your "fair" puts already exist in products like crude oil, FX and interest rate products where prices and interest rates can go negative, or where there's theoretically equal price range in either direction. If there's theoretically unlimited price risk in either direction (which is not the case for equities) than you'll get your equal payout given a 1 standard deviation move in either direction. Don't trade equities or indexes that have limited downside if you want equal payout in your puts. Trade crude, FX, or Bund options. I think you need to take some basic statistics courses and learn a little bit how variance, volatility, probability and price distribution work. Here's a good place to start: https://www.coursera.org/lecture/financial-engineering-1/options-pricing-aZrC4 https://www.optionseducation.org/
Example demonstrating the differrence between PUT and FairPUT, and also the fact that FairPUT is the exact mirror image of CALL: Code: S=100.00 K=100.00 s=30% t=1.0 r=0.0 q=0.0 : CALL : Value=11.923538 Delta=0.559618 MyDelta=0.500000 Gamma=0.013149 Vega=0.394479 Theta=-0.016211 Rho=0.440382 ... PUT : Value=11.923538 Delta=-0.440382 MyDelta=-0.500000 Gamma=0.013149 Vega=0.394479 Theta=-0.016211 Rho=-0.559618 ... FairPUT: Value and other params same as CALL Call, Put, and FairPut all have the same params and do cost all the same. Now let's say the options expire at spot 120: CALL : Payout=20.000000 Profit=8.076462(67.74%) PUT : Payout=0.000000 Profit=-11.923538(-100.00%) FairPUT: Payout=0.000000 Profit=-11.923538(-100.00%) Now let's say the options expire at spot 83.333333: CALL : Payout=0.000000 Profit=-11.923538(-100.00%) PUT : Payout=16.666667 Profit=4.743129(39.78%) FairPUT: Payout=20.000000 Profit=8.076462(67.74%) Do you see the difference in the payouts of PUT and FairPUT ? Spot 120 and Spot 83.333333 are same standard deviations (+/- 0.607739) apart from the strike, so both sides have the same probability to expire at these boundaries. Then of course also the payout has to be equal (to that of CALL), which indeed is the case with FairPUT, but not with PUT. As can be further seen, FairPUT is the exact mirror image of CALL. Q.E.D.
HOW CLOSE ARE THE OPTION PRICING FORMULAS OF BACHELIER AND BLACK-MERTON-SCHOLES? https://arxiv.org/pdf/0711.1272.pdf
@VolSkewTrader, you are talking BS, just stop and play somewhere else instead of disturbing this thread!
Btw, FairPUT works fine with all valid parameters for CALL and PUT, like different strikes than spot, risk-free-rate (the drift), also negative rate, dividends etc.
You just presume a normal distribution, that's it. I'm waiting for you to learn about the volatility smile and flatten vega with your "improved Fair Put"
lognormal is used for pricing the options (ie. calculating the premium), and normaldist is used for FairPUT computations. This is the correct method, as I first tried hard with the lognormal but failed b/c as soon as you add risk-free-rate and/or dividends then it doesn't work with lognormal... So, I'm convinced this method is the correct method. And regarding vola smile etc.: they are IMO still there as the pricing is still done by BSM. But I must admit I hadn't time to test especially this aspect deeper yet, but I'm confident... And: the goal was to create a mirror image of CALL for the FairPUT. So, since it works, then it has to be correct, IMO
A continuation of the above example: Code: Now let's say the options expire at spot 80: CALL : Payout=0.000000 Profit=-11.923538(-100.00%) PUT : Payout=20.000000 Profit=8.076462(67.74%) FairPUT: Payout=25.000000 Profit=13.076462(109.67%)