Put Premium
Returns the value of a European put option as
determined by the BlackScholes formula.

Syntax
(Values in boldface are required; others are
optional) 
PutPremium(UnadjustedPrice,
StrikePrice, Years, Volatility,
RiskfreeRate, DividendYield)
 UndajustedPrice:
The present price of the underlying security (i.e., the
stock price), before adjusting for future dividends.
 StrikePrice:
Also known as "exercise price", the price at which the
underlying security may be bought or sold upon exercise
of the option.
 Years: The time
in years until the option expires. For example,
for an option that expires in one month you may enter
"1/12" or ".083". For an option that expires in
fortyfive days, you may enter "45/365".
 Volatility: The
annualized estimated volatility of the underlying
security, expressed as a percentage greater than zero.
 RiskfreeRate:
The annual riskfree rate of interest which corresponds
to a time period roughly equal to the remaining life of
the option, expressed in continuous compounding terms.
If omitted,
zero is assumed.
 DividendYield:
The annualized dividend yield of the underlying
security, expressed in continuous compounding terms. If
omitted, zero is assumed.


Example 

Notes 
 American put options
differ from European put options in that the American
variety can be exercised at any time up until the
expiration date, while European options can be exercised
only on the expiration date. No exact formula
exists for valuing an American put option precisely, but
the BlackScholes value of its European cousin is
generally considered a good proxy.
 A good estimate for the
riskfree interest rate is the current yield on US
Treasury Bills having approximately the same duration as
the remaining life of the option.
 To estimate dividend
yield, multiply the most recent quarterly dividend by
four, then divide it by the stock price.

Code 
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Function Setup" page.
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