The original column has been published in Dutch on July 18 at DFT.nl / Goeroes / Opties 2.0 – deel 3. De waardering van opties
Valuing Options?
In our previous article of 27 June,
"Options ... what are they again?", you read about the basic features
and concepts of options. From the various options classes to the different expiration
cycles and the value of options. Today we’ll tell you more about the valuation
of options.
Options Value:
An option’s value depends on a
number of fixed basic attributes, in addition to a number of variable
parameters. The fixed attributes include:
 Option Type; Call or Put
 Expiration Date
 Exercise price
Option Type; Call or Put
The option type is always fixed. In
Amsterdam we can choose from Call and Put options.
Call options are worth more at a
higher underlying asset price.
Put options are worth less at a higher
underlying asset price.
Expiration Date
The expiration date of an option is also
fixed.
In the case of monthly options, the
expiration date is normally the third Friday of the month. For weekly options,
it is every Friday.
In the case of American style
options, those with an expiration date that is further away are worth more, or
at least the same, as options with an expiration date that is closer.
This doesn’t apply to European style
options. An expected dividend can, in some cases, lead to a lower value for an
option with an expiration date that is further away.
Exercise Price
The exercise price (strike price) of
an option is fixed.
Call options with a higher strike
price have a lower value than Call options with a lower strike price.
Put options with a higher strike
price have a higher value than Put options with a lower strike price.
Parameters that affect premium formation :
There are also a number of variable
parameters that influence the premium’s formation. These are:
 Price of Underlying Asset
 Remaining Maturity
 Interest Rate
 Volatility
 Dividend
Now let’s see exactly what effect
these parameters have on an option’s value and how we can handle this.
Price of Underlying Asset
The price of the underlying asset
fluctuates. And consequently, so too does the value of options.
At a higher price of underlying
asset, Call options increase in value.
At a higher price of underlying
asset, Put options decrease in value.
Remaining Maturity
The remaining maturity of an option
changes on a daily basis. You can easily calculate the remaining maturity by
determining the number of days from the current date to the expiration date.
For both Call and Put options, the
option’s value will decrease as the expiration date approaches and the remaining
maturity becomes shorter.
Interest Rate
The interest rate used in the
valuation of options, is the interest rate for the currency in which the
options are traded. In Amsterdam, Index and Stock Options are listed in Euros.
The interest rate used for these options is the Euribor.
This interest rate influences the
formation of an option’s price.
In the case of a Call option, the
interest rate has a positive effect on the value of the Call option. A higher
interest rate translates directly into a higher Call option premium.
For a Put option on the other hand,
interest rates have a negative effect on the value of the Put option. A higher
interest rate, therefore, translates into a lower Put option premium.
Volatility
The Volatility or movement factor is
the most important parameter influencing the formation of options premiums.
In both Call and Put options, the
Volatility has a positive influence. Higher Volatility translates directly into
both a higher expected value and a higher option premium.
To get an idea about the level of
volatility, you can always take a look at Historical Volatility. This is an
indicator calculated on the basis of historical underlying asset prices.
The options market also works with
an Implied Volatility, which is also known as Implicit Volatility. This Volatility
indicator gives the precise Volatility level of an option, based on the
assumption that its theoretical value equals the option’s current market price;
because as you know, the market is always right.
Volatility can vary per options
series.
It’s important for options investors
to have a full picture. So make sure you’re well informed up front. That way,
you’ll know if you’re buying or selling at a relatively expensive or
inexpensive price.
Dividend
A (expected) Dividend before expiration affects the value of
an option.
A (expected) Dividend after expiration does not affect the
value of an option.
If a stock goes ExDividend before the
option expires, this will affect the share price and hence the value of the
option.
At a higher (expected) Dividend, a
Call option will decrease in value. This is because the stock price drops
further, resulting in a lower value for the Call option.
At a higher (expected) Dividend, a
Put option will increase in value. This is because the stock price drops
further, resulting in a higher value for the Put option.
Predicting or forecasting Dividends
is notoriously difficult. Fortunately, there are specialist services that stay
on top of this, closely following the stock market on a daily basis and adjusting
expectations according to the current situation / information available.
With options it’s important to take
the correct Dividend amount, and perhaps even more importantly, the correct
ExDividend date, into account. If a Dividend falls immediately before or
directly after expiration, this will certainly have a significant influence on the
price of options.
Be careful. Expected Dividend,
before expiration, is already reflected in the price of an option!
On the ExDividend date you’ll
notice that the share price is reduced by the dividend amount, but that the
price of Call and Put options remain more or less comparable, because the Dividend
has already been included in the price.
This completes our brief overview of
parameters affecting the premium formation of options.
It is conveniently summarised in the
table below:
Parameters

Trend

Call Option Value

Put Option Value

Price of Underlying
Asset

Higher

Higher

Lower

Remaining Maturity

Decreases

Lower

Lower

Interest Rate

Higher

Higher

Lower

Volatility

Higher

Higher

Higher

Dividend

Higher

Lower

Higher

Options ... know your Greeks
In this article we covered the
parameters that influence the value of options. It’s crucial that options
investors estimate this correctly. Because unlike stocks, options don’t react
1:1. So options investors must trade shrewdly and on the basis of sound
information. And that’s perfectly possible. The Greeks can help you with this.
Yep, the Greeks! The Greeks are sensitivity factors that indicate how the value
of an option will react to a change in one of the parameters. You, as an options
investor, can use them to effectively look ahead. We’ll explain this in more
detail in our next article.
Herbert Robijn is founder and director of FINODEX (www.finodex.com). FINODEX develops innovative online
investment tools for private equity and options investors. These cuttingedge
tools allow investors to make a comprehensive market analysis, complex
calculations and appropriate selections, at just the touch of a button.