You should be aware that in purchasing Foreign Exchange Options, your potential loss will be the amount of the premium paid for the option, plus any fees or transaction charges that are applicable, should the option not achieve its strike price on the expiry date.
Certain options markets operate on a margined basis, under which buyers do not pay the full premium on their option at the time they purchase it. In this situation you may subsequently be called upon to pay margin on the option up to the level of your premium. If you fail to do so as required, your position may be closed or liquidated.
If you write an option, the risk involved is considerably higher than buying an option. You may be liable for margin to maintain your position and a loss may be sustained well in excess of the premium received.
By writing an option, you accept a legal obligation to purchase or sell the underlying asset if the option is exercised against you; however far the market price has moved away from the strike. If you already own the underlying asset that you have contracted to sell, your risk will be limited.
If you do not own the underlying asset the risk can be unlimited. Only experienced persons should contemplate writing uncovered options, then only after securing full detail of the applicable conditions and potential risk exposure.