MATH 4514 Financial Economics in Actuarial Science Lecture Note 2 Binomial Tree Pricing Model | The Hong Kong University of Science and Technology
ntroduction
In Chapter 1, we have examined various properties of option
...
MATH 4514 Financial Economics in Actuarial Science Lecture Note 2 Binomial Tree Pricing Model | The Hong Kong University of Science and Technology
ntroduction
In Chapter 1, we have examined various properties of option prices and
the application of options in risk management. It remains to obtain the
pricing formula of options. As mentioned earlier, future price movement of
asset price will significantly affect the options price.
As an example, we consider 1-year European call option with strike price
$51 and consider the following two scenarios:
$48
๐บ๐ = $๐๐
๐1 = $41
Now
(Time 0)
Maturity
(Year ๐)
๐1 = $48
The option will be exercised when
๐บ๐ = $๐๐ (yield a profit of $4). So
the option price will be positive.
$48
๐1 = $50
๐1 = $46
Now
(Time 0)
Maturity
(Year ๐)
๐1 = $48
The option is never exercised at maturity
date and the options price is simply ๐.3 MATH4514 Financial Economics in Actuarial Science
Lecture Note 2: Binomial Tree Pricing Model
In order to derive the pricing formula of options, it is essential to develop a
mathematical model to simulate the future price movement of the asset
price. In this chapter, we shall introduce a binomial tree pricing model
which is the simplest model to model the asset price movement. The
model can be described as follows:
time
0 ๐
โฎ โฎ โฎ
(Period 0) (Period 1) (Period 2) (Period ๐)
ฮ๐ก
The time horizon
แพ0, ๐แฟ is divided into
๐ periods.
Given ๐๐ก, the asset price
either move up to ๐ข๐๐ก and
๐๐๐ก in the next period4 MATH4514 Financial Economics in Actuarial Science
Lecture Note 2: Binomial Tree Pricing Model
Based on this binomial tree model, our goal is to develop a pricing theory
under this model:
๏ท We will study how to price an option (or other derivatives) using no
arbitrage pricing principle and replication technique.
๏ท We will also develop another equivalent pricing approach, which is
known as risk-neutral valuation principle. The principle states that the
option price at time 0 (or at any time ๐ก < ๐) can be expressed as the
present value of expected option payoff (or value) at future time ๐:
๐0 = ๐0(๐0) = ๐โ๐๐๐ผ๐แพ๐๐(๐๐)|๐0แฟ.
๏ท We will also study how to calculate the prices for American options
and path-dependent options.
In addition, we will also study how to construct a binomial tree model
using historical path of asset prices (i.e. model calibration).
๏ท Cox-Ross-rubinstein (CIR) model
๏ท Forward tree model (also called standard binomial tree mode
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