Presentation on theme: "OPTIONS THE TWO BASIC OPTIONS - PUT AND CALL"— Presentation transcript:
1 OPTIONS THE TWO BASIC OPTIONS - PUT AND CALL Other options are just combinations of these.Options are “derivatives” and other derivatives mayinclude optionsThe price of an option is called a “premium” because options are equivalent to insurance and the price of insurance is called a premium.
2 CALL OPTION CONTRACTDefinition: The right to purchase 100 shares of a security ata specified exercise price (Strike) during a specific period.EXAMPLE: A January 60 call on Microsoft (at 7 1/2)This means the call is good until the third Friday of January and gives the holder the right to purchase the stock from the writer at $60 / share for 100 shares.cost is $7.50 / share x 100 shares = $750 premium oroption contract price.
3 PUT OPTION CONTRACTDefinition: The right to sell 100 shares of a security at aspecified exercise price during a specific period.EXAMPLE: A January 60 put on Microsoft (at 14 1/4)This means the put is good until the third Friday of January and gives the holder the right to sell the stock to the writer for $60 / share for 100 shares.cost $14.25 / share x 100 shares = $1425 premium.
4 INTRINSIC AND TIME VALUE An option's INTRINSIC value is its value if it were exercised immediately.An option's TIME value is its price minus its intrinsic value.Microsoft Stock Price = 53 1/4 at the time - October 1987QUESTION: Which Microsoft option has greater intrinsic value? - putQUESTION: Which Microsoft option has greater time value? - call
5 BREAK EVEN CALL BREAKEVEN The stock must rise $14.25 = ( )(premium) for the Call buyer to break even.PUT BREAKEVENThe stock must fall $7.50 = ( ) (premium)for the Put buyer to break even.QUESTION: Which Microsoft option is a better deal? - depends your expectationLook at Options Quotes:
6 HOW TO CALCULATE PROFIT OR LOSS ON OPTIONS TWO PARTSCash flows from premiumsCash flows when you close out positionsIf you close out before expiration, then option value is its market value.If you close out at expiration then:Call value = Max[0, (Stock price - Exercise price)]Put value = Max[0, (Exercise price - Stock price)]
7 EXAMPLE: Both Options on the same stock Sell a put for $4 - strike = $45Buy a call for $2 - strike = $55Assume that the stock price ends at $58premiums putcall -200option values putat expiration call 300Net
8 Assume that the stock price ends at $40 premiums put same as above call -200option value put -500at expiration callNetNote: The value of the put is actually $500 but because you sold the put, it costs you $500 to buy it back.
9 WHAT ARE YOUR PERCENT RETURNS ON THE CALL? Net investment = premium = 200Stock goes to $58Stock goes to $40The holder of opposite positions earns opposite results - zero sum. This is because options are derivative securities created by one individual (the writer (seller)) and bought by another. Original issue of stocks does not have this.
10 HOW TO CLOSE OUT A POSITION IN AN OPTION. sell (or buyback) optionexercise optionlet option expire - worthlessOPTIONS ALLOWlarge leverage but limited downsidehedge a profit
11 CALL STRATEGIES Buy option alone not sure when stock will move =>use long maturitymost leveraged - high strike priceHedgeif you own stock - sell stock - buy optionif you don't own stock - short stock - buy option with high strike priceSell optionnaked - bearish on stock - receive premium
12 PUT STRATEGIES Buy option not sure when stock moves => use long maturitymost leverage - low strike priceHedge - own stock - buy put - protect profitSell put naked - if bullish on stock
14 Illustrate complex options using (click “Examples”, then Money and Finance” then under “Derivatives Valuation” click “Option” then click “more” and select a complex option)Explain the payoff profiles.
15 USE OPTIONS TO CUT UP PRICE DISTRIBUTIONS - NOW CALLED "FINANCIAL ENGINEERING"
16 BLACK - SCHOLES MODELCRUCIAL INSIGHT - it is possible to replicate the payoff to an option by some investment strategy involving the underlying asset and lending or borrowing.We can do this because the option value and the stock value are perfectly correlated – we need to know the hedge ratio (how much the option price increase when the stock price increases).Therefore, we should be able to derive the value of an option from the asset price and the interest rate.
17 C = Call option price today r = risk-free rate THERE IS A HEDGE RATIO BETWEEN THE CALL AND STOCK THAT ALLOWS ONE TO EXACTLY REPLICATE AN OPTIONFor a simplified approach to replication one can use the Binomial Model.1. Assume thatS = Stock price todayC = Call option price todayr = risk-free rateq = the probability the stock price will increase(1-q) = probability the stock price will decreaseu = the multiplicative stock price increase(u > 1 + r > 1)d = multiplicative decrease (0 < d < 1 < 1 + r )Cu = call price if stock price increasesCd = call price if stock decreases
18 The hedge ratio specifies how one asset’s price moves for a given change in another’s. Each period the stock can take on only two values; the stock can move up to uS or down to dS.2. Construct a risk-free hedge portfolio composed of one share of stock and m call options written against the stock. This means the payoffs in the up or down moves will be the same so thatuS – mCu = dS – mCdSolve for m, the hedge ratio of calls to be written on stockm = S(u – d)/(Cu - Cd )
19 3. Because we constructed the portfolio to be risk-free, then (1 + r)(S – mC) = uS – mCuOr4. Substituting for the hedge ratio m,
20 Or to simplify let and So C = [pCu + (1 - p)Cd] / (1 + r) Here, p is called the hedging probability, also called the risk-neutral probability. The potential option payoffs Cu and Cd are multiplied by the risk neutral probabilities and the sum is discounted at the risk-free rate. (Note: the risk-neutral probability for the up (down) move is less (more) than the objective probability that would be used if we discounted the payoffs with a risk-adjusted rate (say a CAPM rate based on option beta) because the value in the numerator must be smaller if we are discounting at the smaller risk-free rate r.
21 Example: Suppose that a stock’s price is S=100 and it can increase by 100% or decrease by 50%. If the risk-free rate is 8% and the exercise price for the call is $125, find the price of the call and the hedge ratio.u = 2, d = 0.5, r = .08Cu = Max [0, 200 – 125] = 75Cd = Max [0, 50 – 125] = 0m = S(u – d)/(Cu - Cd ) = 100(2 – .5)/(75 - 0) = 2
22 Here, the option price moves half as much as the stock’s Here, the option price moves half as much as the stock’s. Therefore, if you own one share of the stock in this example, you can hedge, that is, eliminate your risk, by selling two calls.To see how hedging works, form a hedged portfolio by buying one share and selling 2 options and find its risk-free end-of-period value. (Why is this risk-free?)Stock goes:Down UpOwn the stockSold 2 options
23 Find the present value of the portfolio’s end value by discounting at the risk-free rate. In this case, 50/(1+.08)=46.30.You borrow this amount of money and add (S – 46.30) = (100 – 46.30) = $53.70 of your own money to buy one share. This leveraged position in the stock should give the same return as owning two calls.To see this note that in one year you pay off the loan and you will have[= (1+.08)] if stock goes to 200or [= (1+.08)] if the stock goes to 50.
24 Set the present value of the hedged portfolio equal to its discounted risk-free value and solve for C.Here, S - 2 C = C = => C=26.85.
25 GET THE PUT VALUE - PUT/CALL PARITY FORMULA Put Price = C - S + E/(1 + risk-free rate)tFor this case:Put = /( )1 = 42.6.This model shows that, to get an option value, ones needs to know thecurrent stock priceoption’s exercise pricerisk-free rateoption maturitystock price volatility.
26 BLACK-SCHOLES MODEL - A NEARLY EXACT OPTION PRICING MODEL C0 = P0N(d1) - E e-rt N(d2)where Price of Stock = P0Exercise price = ERisk free rate = rTime until expiration in years = tNormal distribution function = N( )Exponential function (base of natural log) = e
27 Note: Here the hedge ratio is represented by N(d1) and N(d2) where:where Standard deviation of stocks return = sNatural log function = ln
28 NOTE: the call price is a weighted average of the stock price and the present value of the exercise price (replicating strategy – buy N(d1) shares and sell N(d2) bonds).The weights are cumulative probabilities of a normal distribution. These probabilities are sometimes described as “risk-adjusted” probabilities. For each (d), we have the term ln(P0/E) which is the percent by which the stock price exceeds the exercise price (i.e. is in the money). Clearly, if the stock price exceeds the exercise price by a large percentage, the more likely the option will be valuable (i.e. exercised) at expiration. But note that ln(P0/E) is divided by so that the probability is adjusted for the stock’s risk and the time to expiration. A call on a risky stock (relatively large ) in the money by a given percent has less probability of staying in the money.
29 TO GET THE VALUE OF THE CALL, C0 EXAMPLE: ASSUMEPrice of Stock P0 = 36Exercise price E = 40Risk free rate r = .05time period 3 mo. t = .25Std Dev of stock return s = .50Substitute into d1 and d2.
30 Substitute d1, d2 and other variables in the main equation C0 = 36N(-.25) - 40e-.05(.25)N(-.50)Look up in the normal table for d to get N(d).here N(d1) = N(-.25) = .4013and N(d2) = N(-.50) =.3085Substitute in the main equation
31 USE PUT CALL PARITY FORMULA TO GET PUT PRICE To see why this holds, look at the stock price distribution and how the put gives you the left tail of the distribution. Then see that shorting the stock and buying the call leaves you with the same left tail. Or see that payoff at time t=0 is equal on both sides no matter what price is.EXAMPLE - use info above - you need the call price= = 5.76
32 BUYING A CALL OPTION IS LIKE BUYING STOCK USING MARGIN MONEY BUYING A PUT IS LIKE SELLING A STOCK SHORT AND INVESTING (LENDING) PROCEEDS.One difference is that with an option, the most you can lose is 100%.With margin you can lose more.The attraction of an option is this limited lossfeature - this is why a premium is paid.The more volatile the stock the more valuable thisfeature is. (see futuresource.com –S&P volatility term structure).
33 HOW MARGIN WORKS EXAMPLES: USING MARGIN MONEY - ignore interest Assume: Required margin = 60%Stock Price = 75Investment = 30,000Buy without margin borrowingHow many shares can you buy? - 30,000/75 = 400Suppose price goes to 100
34 Suppose price goes to 40Buy with margin borrowing - M = investable funds= your funds/margin rateHow much do you have to invest counting margin borrowing?M = 30,000/.60 = 50,000=> you borrow 20,000 and buy 50,000/75 = 667 shares
35 Suppose price goes to 100Note: Remember your investment at risk is still just 30,000- must pay back 20,000 marginSuppose price goes to 40Selling short and having to put up 60% margin gives the same returns but opposite signs.
36 A stock is an option on the value of the firm if there is debt in the capital structure. the value of the debt is the strike price. shareholders exercise their option to own the firm if the firm's value exceeds to value of debt, otherwise, they default and give the firm to the debtholders.Initial Values Firm Value FallsFirm value 10mm 3mmDebt value 5mm 3mmEQUITY value 5mm 0mm