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Derivatives & Risk Management




                    Notes


                                      Task  Consider a European call option on a stock when there are ex-dividend dates in two
                                     months and five months. The dividend on each ex-dividend date is expected to be $ 0.5.
                                     The current price is $ 40, the exercise price is $40, the stock price volatility is 30% per
                                     annum, the risk free rate of interest is 9% per annum,  and the time to maturity is six
                                     months.

                                   Self Assessment

                                   State the following are true or false:
                                   11.  In finance, the binomial options pricing model provides a generalisable numerical method
                                       for the valuation of options.
                                   12.  The Black and Scholes Model was first proposed by Cox, Ross and Rubinstein (1979).
                                   13.  The fundamental insight of Black and Scholes is that the put option is implicitly priced if
                                       the stock is traded.
                                   14.  The Black-Scholes formula is a mathematical formula for the theoretical value of so-called
                                       European put and call stock options that may be derived from the assumptions of the
                                       model.
                                   15.  The binomial tree represents different possible paths that may be followed by the stock
                                       price over the life of the option.


                                   8.4 Summary

                                      The price of an option contract is that amount which is paid by the option buyer to the
                                       option seller. This is otherwise, known as option premium.

                                      The different factors or determinants which effect option prices are Current Stock Price,
                                       Exercise Price, Volatility, Risk free Interest Rates, Cash Dividends and Time to Expiration.
                                      To better understand the significance and option pricing techniques, we have to go through
                                       two important models of option valuation like Black-Scholes model and Binomial model.
                                      This unit also discusses at large the Put-Call  parity under the 'with dividend' and 'no
                                       dividend' model.
                                      Put-call parity is a classic application of arbitrage-based pricing – it does not instruct us on
                                       how to price either put or call options, but it gives us an iron law linking the two prices.

                                      The put-call parity states  that the difference in price between  a call-option and a  put-
                                       option with the same terms should equal the price of the underlying asset less the present
                                       discounted value of the exercise price.
                                      In finance, the binomial options pricing model provides a generalisable numerical method
                                       for the valuation of options.

                                      The binomial model was first proposed by Cox, Ross and Rubinstein (1979).
                                      The Black-Scholes model, often simply called Black-Scholes, is a model of the varying
                                       price over time of financial instruments, and in particular stock options.








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