Understanding a binary option
In finance, a binary option is a type of option where the payoff is either some fixed amount of some asset or nothing at all. The two main types of binary options are the cash-or-nothing binary option and the asset-or-nothing binary option. The cash-or-nothing binary option pays some fixed amount of cash if the option expires in-the-money while the asset-or-nothing pays the value of the underlying security. Thus, the options are binary in nature because there are only two possible outcomes. They are also called all-or-nothing options, digital options (more common in forex/interest rate markets), and fixed return options (FROs) (on the American Stock Exchange).
When buying a binary option the potential return it offers is certain and known before the purchase is made. Binary options can be bought on virtually any financial product and can be bought in both directions of trade either by buying a “Call”/“Up” option or a “Put”/“Down” option. This means that an investor can go long or short on any financial product simply by buying a binary option. Binary options are offered against a fixed expiry time which may be e.g. 30 seconds and up to 30 minutes, an hour ahead or to the close of the trading day.
For example, a purchase is made of a binary cash-or-nothing call option on XYZ Corp’s stock struck at $100 with a binary payoff of $1000. Then, if at the future maturity date, the stock is trading at or above $100, $1000 is received. If its stock is trading below $100, nothing is received.
In the popular Black–Scholes model, the value of a digital option can be expressed in terms of the cumulative normal distribution function. Due to the difficulty in hedging binary options that are near expiry, they are much less traded than vanilla options, but can be approximated with vertical spreads.
Example of a binary options trade
A trader who thinks that the EUR/USD price will close at or above 1.2500 at 3:00 p.m. can buy a call option on that outcome. A trader who thinks that the EUR/USD price will close at or below 1.2500 at 3:00 p.m. can buy a put option or sell a call option contract.
At 2:00 p.m. the EUR/USD price is 1.2490. The trader believes this will increase, so he buys 10 call options for EUR/USD at or above 1.2500 at 3:00 p.m. at a cost of $40 each.
The risk involved in this trade is known. The trader’s gross profit/loss follows the ‘all or nothing’ principle. He can lose all the money he invested, which in this case is $40 x 10 = $400, or make a gross profit of $100 x 10 = $1000. If the EUR/USD price will close at or above 1.2500 at 3:00 p.m. the trader’s net profit will be the payoff at expiry minus the cost of the option: $1000 – $400 = $600.
The trader can also choose to liquidate (buy or sell to close) his position prior to expiration, at which point the option value is not guaranteed to be $100. The larger the gap between the spot price and the strike price, the value of the option decreases, as the option is less likely to expire in the money.
In this example, at 3:00 p.m. the spot has risen to 1.2505. The option has expired in the money and the gross payoff is $1000. The trader’s net profit is $600.