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A
barrier option is a
path dependent option that has one of two features:
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A
knockout feature causes the option to immediately terminate if
the underlier reaches a specified barrier level, or
-
A
knock-in
feature causes the option to become effective only if the underlier first
reaches a specified barrier level.
Premiums are paid in advance. Due to the contingent nature of
the option, they tend to be lower than for a corresponding vanilla option.
Consider a knock-in call option
with a strike price of EUR 100 and a
knock-in barrier at EUR 110. Suppose the option was purchased when the underlier was at
EUR 90.
If the option expired with the underlier at EUR 103, but the underlier never
reached the barrier level of EUR 110 during the life of the option, the option
would expire worthless. On the other hand, if the underlier first rose to the
EUR 110 barrier, this would cause the option to knock-in. It would
then be worth EUR 3 when it expired with the underlier at EUR103. This is
illustrated in Exhibit 1:
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An up-and-in barrier call option expires
worthless unless the underlier value hits the barrier at some time
during the life of the option. |
The particular option in this
example is known as an "up-and-in" option because the underlier must first go
"up" to the barrier before the option knocks "in."
In all, there are eight flavors of barrier options
comprising European puts or calls having barriers that are:
up-and-in,
down-and-in,
up-and-out, or
down-and-out.
Of the eight, four either knock-in or knockout when they
are in-the-money. These are called
reverse barrier options. They can pose significant hedging
challenges for the issuer.
Alternative structures include multiple barriers or
barriers incorporated into other types of derivatives. For example,
binary
options can be structured with barriers.
Merton priced a down-and-out call option in his seminal (1973)
paper. The classic paper providing analytic pricing formulas for barriers
is Reiner and Rubinstein (1991). See Haug (1997)
for an alternative treatment of the same formulas. A shortcoming of
analytic formulas is their use of a single implied volatility. Because
barrier options are path-dependent, it is desirable to model a term
structure of implied volatilities. See Taleb (1996).
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Asian option An option whose
expiration value depends on
the average value of an underlier over a specified period.
binary
option A type of option which features a
discontinuous expiration value.
derivative instrument An instrument
which derives its value from the value of other financial
instruments. Article includes a list of vanilla and exotic derivatives.
lookback option
A path dependent option whose
payoff depends upon the maximum or minimum underlier value
achieved during the entire life of the option.
option pricing theory The
body of financial theory used by financial engineers to value options and other
derivative instruments.
path
dependence A property of certain exotic options whose terminal
value depends upon the path taken by the underlier during the life
of the option. |
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Ads by Contingency Analysis
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Haug (1997)
and Bryis et al (1998)
describes classic pricing methodologies. Chriss (1997)
includes an accessible but sophisticated treatment of barrier
option pricing. Taleb (1996)
has two chapters on barrier options, primarily from a trading and
dynamic hedging perspective. Das (2004)
provides an in-depth discussion of barriers from a trader's
perspective.
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Merton, Robert C. (1973). Theory of
rational option pricing, Bell Journal of Economics and
Management Science, 4 (1), 141-183. Available in Merton (1990).
Reiner, Eric and
Mark Rubenstein (1991). Breaking down the barriers, Risk, 4
(8), 28-35. |
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