berk chapter 20: financial options

Download Berk Chapter 20: Financial Options

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  • 1.Chapter 20 Financial Options

2. Chapter Outline

  • 20.1 Option Basics
  • 20.2 Option Payoffs at Expiration
  • 20.3 Put-Call Parity
  • 20.4 Factors Affecting Option Prices
  • 20.5 Exercising Options Early
  • 20.6 Options and Corporate Finance

3. Learning Objectives

  • Define the following terms: call option, put option, exercise price, strike price, exercising the option, expiration date, American option, European option, in-the-money, and out-of-the-money.
  • Compute the value of a call or a put option at expiration.
  • List the rights and obligations of the buyer of the option and the seller of the option.
  • Use put-call parity to solve for the call premium, the put premium, the stock price, the strike price, or the dividend.
  • Discuss the following factors that influence call and put option values: stock price, strike price, and volatility.

4. Learning Objectives (cont'd)

  • Describe arbitrage bounds for option prices.
  • Explain why it is never optimal to exercise an American call option early on a non-dividend-paying stock, and why it is sometimes optimal to exercise an American put option early.
  • Explain the use of option modeling to value equity.
  • Describe how corporate debt can be viewed as a portfolio of riskless debt and a short position in aput option.

5. 20.1 Option Basics

  • Financial Option
    • A contract that gives its owner the right (but not the obligation) to purchase or sell an asset at a fixed price as some future date
  • Call Option
    • A financial option that gives its owner the right to buy an asset

6. 20.1 Option Basics (cont'd)

  • Put Option
    • A financial option that gives its owner the right to sell an asset
  • Option Writer
    • The seller of an option contract

7. Understanding Option Contracts

  • Exercising an Option
    • When a holder of an option enforces the agreement and buys or sells a share of stock at the agreed-upon price
  • Strike Price (Exercise Price)
    • The price at which an option holder buys or sells a share of stock when the option is exercised
  • Expiration Date
    • The last date on which an option holder has the right to exercise the option

8. Understanding Option Contracts (cont'd)

  • American Option
    • Options that allow their holders to exercise the option on any date up to, and including, the expiration date
  • European Option
    • Options that allow their holders to exercise the option only on the expiration date
      • Note: The names American and European have nothing to do with the location where the options are traded.

9. Understanding Option Contracts (cont'd)

  • The option buyer (holder)
    • Holds the right to exercise the option and has along positionin the contract
  • The option seller (writer)
    • Sells (or writes) the option and has ashort positionin the contract
    • Because the long side has the option to exercise, the short side has an obligation to fulfill the contract if itis exercised.
  • The buyer pays the writer a premium.

10. Interpreting Stock Option Quotations

  • Stock options are traded on organized exchanges.
  • By convention, all traded options expire on the Saturday following the third Friday of the month.
  • Open Interest
    • The total number of contracts of a particular option that have been written

11. Table 20.1Option Quotes for Amazon.com Stock 12. Interpreting Stock OptionQuotations (cont'd)

  • At-the-money
    • Describes an option whose exercise price is equal to the current stock price
  • In-the-money
    • Describes an option whose value if immediately exercised would be positive
  • Out-of-the-money
    • Describes an option whose value if immediately exercised would be negative

13. Interpreting Stock OptionQuotations (cont'd)

  • Deep In-the-money
    • Describes an option that is in-the-money and for which the strike price and the stock price are very far apart
  • Deep Out-of-the-money
    • Describes an option that is out-ofthe-money and for which the strike price and the stock price are very far apart

14. Textbook Example 20.1 15. Textbook Example 20.1 (cont'd) 16. Alternative Example 20.1

  • Problem
    • It is December 30, 2009 and you have decided to purchase 25 February put contracts on the DJIA with an exercise price of $106.

17. Alternative Example 20.1

  • Problem (continued)
    • How much money will this purchase cost you?
    • Is this option in-the-money or out-of-the-money?

18. Alternative Example 20.1

  • Solution
    • The ask price is $3.30 per contract.
    • The total cost is:
      • 25 $3.30 100 = $8,250
    • Since the strike price exceeds the current price, ($105.49) the put option is in-the-money.

19. Options on Other Financial Securities

  • Although the most commonly traded options are on stocks, options on other financial assets, like the S&P 100 index, the S&P 500 index, the Dow Jones Industrial index, and the NYSE index, are also traded.

20. Options on Other FinancialSecurities (cont'd)

  • Hedge
    • To reduce risk by holding contracts or securities whose payoffs are negatively correlated with some risk exposure
  • Speculate
    • When investors use contracts or securities to place a bet on the direction in which they believe the market is likely to move

21. 20.2 Option Payoffs at Expiration

  • Long Position in an Option Contract
    • The value of a call option at expiration is
      • WhereSis the stock price at expiration,Kis the exercise price,Cis the value of the call option, andmaxis the maximum of the two quantities in the parentheses

22. Figure 20.1Payoff of a Call Option with a Strike Price of $20 at Expiration 23. 20.2 Option Payoffs at Expiration (cont'd)

  • Long Position in an Option Contract
    • The value of a put option at expiration is
      • WhereSis the stock price at expiration,Kis the exercise price,Pis the value of the put option, andmaxis the maximum of the two quantities in the parentheses

24. Textbook Example 20.2 25. Textbook Example 20.2 (cont'd) 26. Alternative Example 20.2

  • Problem
    • You own a put option on Dell stock with an exercise price of $17.50 that expires today.Plot the value of this option as a function of the stock price.

27. Alternative Example 20.2 (cont'd)

  • Solution
    • Let S be the stock price and P be the value of the put option.The value of the option is P= max(12.50 - S,0)

28. Short Position in an Option Contract

  • An investor that sells an option has an obligation.
    • This investor takes the opposite side of the contract to the investor who bought the option. Thus the sellers cash flows are the negative of the buyers cash flows.

29. Figure 20.2Short Positionin a Call Option at Expiration 30. Textbook Example 20.3 31. Textbook Example 20.3 (cont'd) 32. Profits for Holding an Option to Expiration

  • Although payouts on a long position in an option contract are never negative, the profit from purchasing an option and holding it to expiration could be negative because the payout at expiration might be less than the initial cost of the option.

33. Figure 20.3Profit from Holdinga Call Option to Expiration 34. Textbook Example 20.4 35. Textbook Example 20.4 (cont'd) 36. Returns for Holding an Optionto Expiration

  • The maximum loss on a purchased call option is 100% (when the option expires worthless).
  • Out-of-the money call options are more likely to expire worthless, but if the stock goes up sufficiently it will also have a much higher return than an in-the-money call option.
  • Call options have more extreme returns than the stock itself.

37. Returns for Holding an Optionto Expiration (cont'd)

  • The maximum loss on a purchased put option is 100% (when the option expires worthless).
  • Put options will have higher returns in states with low stock prices.