Lecture Tip: You may wish to emphasize the asymmetrical nature of
options payoffs by contrasting the positions of options buyers and options
writers. For example, call buyers hope that the value of the underlying
asset rises before their option expires. Their potential gain is unlimited,
while their loss is limited to the price paid (the premium) for the option
contract.
Call writers, on the other hand, hope that the value of the underlying
asset falls (or, at least, doesn’t rise); their gain is limited to the premium
received, while their potential (opportunity) loss is unlimited. Writers of
covered calls possess the underlying asset at the time the call is written, so
the cost of delivering the underlying asset, should it become necessary, is
known. However, the opportunity cost of having to sell the asset at a
below market price is unknown and unlimited. Writers of naked calls do
not own the underlying asset and must purchase it at the prevailing
market price if the option is exercised. Their actual potential cost (the
amount of cash they have to come up with) is unknown and unlimited. For
this reason, many people view writing naked options as much riskier than
writing covered options.
Options are a zero-sum game (ignoring transaction costs). This is because
one person gains and one person loses by the same amount. The
transaction occurs because you don’t know which you will be ex ante.
Thus, to calculate the gain or loss for a seller, you can calculate the gain or
loss for the buyer and change the sign. This makes the payoff diagrams
mirror images.
Slide 22.15 Call Option Payoffs
Slide 22.16 Put Option Payoffs
Slide 22.17 Option Diagrams Revisited
5. Option Quotes
Chicago Board Options Exchange (CBOE) – the largest organized stock
options exchange. Virtually all listed options are American options. (Even
in Europe, most options are American, not European.) An option is
described as “Firm/Expiration month/ Strike price/Type.”
Contracts are generally for 100 shares (index options provide their basis in
the quote), so a contract will cost 100*price.
Options expire on the Saturday following the third Friday of the expiration
month.
Slide 22.18 –
Slide 22.24 Option Quotes