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Chapter 20. Option Valuation and Strategies. Option Valuation and Strategies. Option valuation determines what an option is worth Option strategies means to use options as speculative or risk-management tools. Option Value. What determines line DE’s position?.
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Chapter 20 Option Valuation and Strategies
Option Valuation and Strategies • Option valuation • determines what an option is worth • Option strategies • means to use options as speculative or risk-management tools
Option Value • What determines line DE’s position?
Black / Scholes Option Valuation Model • Value of an option depends on • price of the stock • strike price • time to the option's expiration • variability of the stock’s return • rate of interest
Black / Scholes Model in Equation Form • V0 = Ps x F(d1) - Pe/erT x F(d2)
Black / Scholes Option Valuation Model • Except for the variability of a stock's return, all the variables are observable • The historical standard deviation of a stock's return is often used to measure the current variability of a stock's return
The Anticipated Relationships (for calls) • Higher stock price - higher valuation • Lower strike price - higher valuation • Longer term - higher valuation • Increased variability - higher valuation • Higher interest rate - higher valuation
Variability • Generally increased variability (increased risk) is associated with lower security valuationsBUT • More variability increases the likelihood the stock's price may rise • The higher stock price increases a call option's valuation
Interest Rates • Generally higher interest rates are associated with lower security valuationsBUT • Higher interest rates reduce the present value of the call option's strike price. This reduction increases the option's valuation
Black / Scholes • Black/Scholes uses a normal probability distribution • As the probability of an option being exercised rises, so does the valuation
Put-Call Parity • The values of stocks, options, and debt instruments are interrelated • Put-call parity verifies the interrelationships
Price of Stock • The price of a stock must equal • price of the call plus • present value of the strike price minus • price of the put
Put-Call Parity Equation • Ps = Pc + Pe / (1 + i) - Pp • If the two sides are not equal • an opportunity for a risk-free arbitrage exists • If price of one of the four components changes, the price change is transferred to the remaining three
Hedge Ratio • Determines the number of options necessary to offset a price movement in a stock • Is derived from the Black/Scholes valuation model
Covered Put Strategy • Short the stock and sell the put • The opposite of the "covered call" • buy the stock and sell the call • Takes advantage of the declining time premium paid for the put
Covered Put Strategy • Limited profit but unlimited potential loss
Protective Call Strategy • Short the stock and buy the call • The opposite of the "protective put" • buy the stock and the put • Protects from the price of the stock rising
The Straddle • Buy a call and a put with the same strike price • Takes advantage of • major movements in the price of the stock • uncertainty concerning the direction of change in a stock’s price
The Straddle • Buying a straddle generates profits only if the price of the stock moves sufficiently to cover the cost of the two options purchased
The Straddle • Writing a straddle is selling a call and a put with the same strike price • Is profitable if the price of the stock is stable
The Bull Spread • Requires two options with different strike prices and the same expiration date • To construct a bull spread using calls • buy the option with the lower strike price • sell the option with the higher strike price
The Bear Spread • Requires two options with different strike prices and the same expiration date • To construct a bear spread using calls • sell the option with the lower strike price • buy the option with the higher strike price
Bull and Bear Spreads • Bull and bear spreads have limited potential profits • Bull and bear spreads have limited potential for loss
Bull and Bear Spreads • Profits and losses on bull and bear spreads are mirror images
The Butterfly Spread • Requires three options with • different strike prices and • the same expiration date • Buy the one each of the options with the extreme strike prices and sell two of the options with the middle strike price
The Butterfly Spread • The process may be reversed: Sell one each of the options with the extreme strike prices and buy two of the options with the middle strike price
The Butterfly Spread • Profits and losses from the two butterfly spreads are mirror images • The butterfly spread has limited potential profits but limited potential for loss
Collars • Used when an investor desires to lock-in a large gain • Sell a call at one strike price and • Buy a put with a lower strike price
Collars • The cash inflow from the sale offsets the cost of the put • The put protects the investor from a decline in the price of the stock