PFE Chapter 23: Facts about option prices page 1
CHAPTER 23: OPTION PRICING FACTS
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This version: September 22, 2002
Chapter contents
Overview......................................................................................................................................... 2
22.1. Fact 1: Call price of an option >
)
0
,0Max S PV X
−
..................................................... 3
22.2. Fact 2: It’s never worthwhile to exercise a call early. ......................................................... 8
22.3. Fact 3: Put-call parity
)
00 0
Put Call PV X S=+ −.............................................................. 9
22.4. Fact 4: Bound on an American put option price:
0
,0PMaxXS>−
............................. 12
22.5. Fact 5: Bounds on European put option prices
)
0
,0PMaxPVX S
>−
...................... 12
22.6. Fact 6: You might find it optimal to early-exercise an American put on a non-dividend
paying stock .................................................................................................................................. 14
22.7. Fact 7: Option prices are convex ....................................................................................... 14
Summary....................................................................................................................................... 19
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Notice: This is a preliminary draft of a chapter of Principles of Finance by Simon Benninga
(benninga@wharton.upenn.edu
). Check with the author before distributing this draft (though
you will probably get permission). Make sure the material is updated before distributing it. All
the material is copyright and the rights belong to the author.