Derivatives Articles

Black Scholes Option Pricing Model


The Black Scholes option model is a simple formula which can be used for valuing European Options.  The Black Scholes model cannot be used for valuing other exotic types of options such as American Options or Asian Options as it cannot incorporate  exercise features or any path dependencies (such as the knock in/out features of Barrier Options). The primary advantages of the Black Scholes model are its speed and accuracy in valuing simple options.

The Black Scholes model has five main inputs – Spot Price, Strike Price, Time to Maturity, Interest Rate and Volatility. For more details on these see Black Scholes Inputs.

Derivatives ONE  features a free Black Scholes pricing model for valuing European options on Stocks, Currencies, Commodities and Futures
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Barrier Option Pricing


A Barrier option becomes active or inactive when a pre-set price barrier is breached. For example an “up-and-in” call option would only be active if at some point during the option’s life the price of the underlying exceeded the barrier, if it failed to do so it could not be exercised regardless of whether it finished in-the-money or not. Similary a “down-and-out” put option would be automatically cancelled if, during the option’s, life the underlying asset’s price fell below the barrier.

Double barrier options have two barriers, one above the spot price (ie the market price of the asset at the start of the option’s term) and one below the spot.
Barrier options are always less expensive than equivalent European/American options as there is always a probability that the options will be knocked out or not be knocked in. The only input in addition to the black scholes inputs is barrier level and the barrier type (ie knock in or knock out).

Barrier options cannot be valued using a Black Scholes model and are typically valued using a monte-carlo or binomial option pricing model

Derivatives ONE features a free valuation tool for pricing a single and double Barrier Options on Stocks, Currencies, Commodities and Futures.

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Asian Options Pricing


An Asian Option is based on the average price of the underlying asset over the life of the option and not a set strike price. Asian options are often used as they more closely replicate the requirements of firms exposed to price movements on the underlying asset. For example, an airline might purchase a one year Asian call opton on fuel to hedge its fuel costs. The airline will be charged the market rate for fuel throughout the life of the option and so an Asian option based on the average rate during the period would be preferable to an option based on a single strike price.

The average can be either the Arithmetic Average (ie the standard mean) or the Geometric Average (which is the mean when assuming all price moves are in percentages not absolute values).
The only extra input required in addition to the black scholes inputs is the Existing Average which is the average to date of the underlying price (if the option is being valued at its inception then this is set equal to the spot price)

Derivatives ONE features a free valuation model which values Asian options on Stocks, Currencies, Commodities and Futures.

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European Options


European Options are options which are only exercisable on the expiry date of the option and are normally valued using the Black Scholes option pricing forumla. There are only five inputs to the classic Black Scholes model : spot price, strike price, time until expiry, interest rate, and volatility. As such European options are typically the simplest options to value The dividend or yield on the underlying asset can also be an input on some extentions of the model. In contrast American Options can be exercised at any time up until and including the expiry date of the option.

The term European is confined to describing the exercise feature of the option (ie exercisable only on the expiry date) and is does not describe the geographic region of the underlying asset. For example, a European Option can be issued on a stock of a company listed on an Asian exchange.

Derivatives ONE features a free valuation tool for European and American options

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American Option Pricing


An American Option is an option which can be exercised at any time up to and including the expiry date of the option. This added flexibility over European options results in American options having a value of at least equal to that of an identical European option, although in many cases the values are very similar as the optimal exercise date is often the expiry date.

The early exercise feature of American options complicates the valuation process as the standard Black-Scholes continuous time model cannot be used. The most common model for valuating American Options is the binomial model. The binomial model begins by evolving an seet price over a lattice with the asset price moving either up or down at each node of the the lattice. Once a lattice of asset prices has been determined the model iterates back through the lattice of prices to determine at each node if early exercise is optimal or not. The binomial model is simple to implement but is slower and less accurate than ‘closed-form’ models such as Black Scholes.

DerivativeOne features a binomial model for valuing american options on Stocks, Currencies, Commodities and Futures

Option Calculator


Derivatives ONE features a free option calculator

Interest Rate Swap Calculator


Derivatives ONE features a free interest rate swap calculator. The calculator values the swap, calculates the accrued interest on both legs of the swap and provides sensitivity measures such as the PV01 of the swap.

Interest Rate Cap and Floor Valuation


A Cap is a series of call options on an interest rat, whereas a Floor is a series of put options.
On each refix date the cap holder will receive a payoff of the excess (if any) of the market interest rate over the cap rate multiplied by the notional amount. Thus if the market rate is 4% and the cap set at 3% with a notional of 1,000,000, the cap holder would receive a payoff of 10,000 (0.04 – 0.03 x 1000000).
Caps are typically used by borrowers to place a ceiling on their borrowing cost. For example a corporate which borrows by issuing a 5 year floating rate note which pays interest every 3 months at the market rate could purchase a 5 yr 3M refixing cap at 6% to ensure that the payment never exceeds 6%.

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