Binomial Pricing and BSM Flashcards
What are factors affecting price of an option
- Current price of the underlying asset
- Time of expiration
- Strike price
- Rate of interest
- Random characteristics of the price of the underlying asset
What are the stochastic assumptions of binomial and black Scholes option
- Price is distributed lognormally where the logarithm of the future price follows the normal distribution
- Stock price follows a discrete time distribution for binomial model
- BSM follows a continuous time distribution union
- BSM and binomial option pricing are capable of derving an exact option price on arbitrage alone
What is valuation by replication
Constructing a portfolio containing the stock and diskless asset who’s payoffs are equal to the derivative at every time period and balance needs to continuously achieve this
What is the derivative of the expected payoff discounted with in a risk neutral world
Risk free rate
Why is stock expected return irrelevant
Valuing an option in the real world, the probability of up and down movements in the real world are irrelevant and this is already incorporated in the stock price
What are the assumptions of the binomial model
- Assume that there’s no arbitrage opportunities
- Portfolio has no risk
- There’s two securities: Stock and stock option
- there’s 2 possible outcomes
- Portfolio is diskless when delta is chosen so that the final value of the portfolio is the same for both alternatives
What are the assumptions of the risk neutral world
All individuals are indifferent of risk and expected return on all securities is the risk free rate
What are implications of American options
American options will be greater than European option payoff therefore it should be exercised early
What are the implications of option price
Always equal to expected payoff in a risk neutral world discounted at the risk free rate
What is delta
Ratio of change in price of the stock option to the change in the price of the underlying stock
What are the signs for delta call
Positive
What are the signs of delta put
Negative
What is Girsanov’s theorem
Moves from a world with one set of risk and expected growth rates change but volatilities stay the same
What are the assumptions on options on stock indices
- Assume that stocks of underlying assets provide a dividend yield of rate q
- Valuation of an option on stock index is similar to valuation of option on stock paying a known dividend yield
What are the assumptions for foreign currencies
Foreign currencies can be regarded as an asset providing a yield at a risk free rate of interest