An option contract is a binding agreement between two parties in which the buyer has the right, but not the obligation, to purchase or sell an underlying security at a specific price on or before a certain date.The Expiration Time of an options contract is the exact date and time when it is rendered null and void. If the buyer does not exercise their right by this date, then they lose their investment. Conversely, if the seller does not deliver on their obligation by this date, then they are liable to pay damages to the buyer.