Does anyone have Implied Volatility AFL (reverse Black Scholes using Newton Raphson)?
you can check the Black scholes AFL as given below , right click on parameter to set Implied Volatility etc
//------------------------------------------------------------------------------
//
// Black Scholes Option Pricing returns the Fair Value of call and put
// options.
//
//------------------------------------------------------------------------------
StockPrice = Param(“stockPrice”,81,1,200,1); //Stock Price
Timedays = Param(“DaysToExpire”,30,1,300,1); //Time to expiry ( days to exp/365 )
StrikePrice = Param(“StrikePrice”,75,1,300,1); //strike Price of Option to evaluate
InterestRate= Param(“InterestRate”,0.06,0.01,0.11,0.001); //prevailing interest rate
VKnown =Param(“Volatility”,0.30,0.10,0.50,0.001);//You can insert Known volatility here , Implied Volatility.
x = (ln(stockPrice/strikePrice) + (interestrate + Vknown*Vknown/2)timedays)/(Vknownsqrt(timedays));
P = 0.2316419;
bb1 = 0.31938153;
bb2 = -0.3565638;
bb3 = 1.78147794;
bb4 = -1.821256;
bb5 = 1.33027443;
pi = 3.141592654; // PI
A2 = 1/sqrt(2pi);
A3 = exp(-(x^2)/2);
y= a2a3;
A4 = exp(-interestratetimedays);
t1 = 1/(1+ Px);
A5=(bb1t1)+(bb2t1^2) +( bb3t1^3)+(bb4t1^4)+(bb5t1^5);
/***********************************************************/
//Standard Normal Distribution Function of ( x )
N = 1- y *A5 ;
/***********************************************************/
// Solves for ( X1 )
X1=x-Vknownsqrt(TIMEdays);
y1=1/sqrt(2pi);
N0=exp(-(x1^2)/2);
T2=1/(1+ PX1);
A6=(bb1t2)+(bb2t2^2) +( bb3t2^3)+(bb4t2^4)+(bb5t2^5);
A7=exp(-interestratetimedays);
y2=y1*n0;
//
/ Standard Normal Distribution Function OF ( x1 )/
/*/
N2= 1-y2 * A6;
/************ CALL OPTION FAIR VALUE************/
Call = stockPrice * N - strikePrice * A4 * N2;
/************ PUT OPTION FAIR VALUE*************/
Put = Call - stockprice + strikeprice*A7;
Filter = 1;
SetOption(“nodefaultcolumns”,1);
AddColumn(stockPrice,“AssetP”,2.2);
AddColumn(strikeprice,“StrikeP”,1.2);
AddColumn(InterestRate100,“InterestRate%”,1.2);
AddColumn(VKnown100,“Volatility%”,1.2);
AddColumn(timedays,"DaysToExpire ",1);
AddColumn(Call,“Call FV”,1.2);
AddColumn(put,“Put FV”,1.2);
//Notes
/* AA window
- Select current symbol ( could be any stock, output is not associated
with the current stock).- n last quotations
- n = 1
- Use the Parameters button to make user selections
- Click explore */