Option is a legal agreement between buyer and seller to buy or sell security at an agreed price in a certain period of time. It is quite similar to insurance that you pay an amount of money in order that your property is protected by the insurance company. The difference between these two is option can be traded whereas, insurance policy cannot be traded. There are two types of option contracts; call options and put options. We buy call option when we expect the security price will go up and buy put option when we expect the security price will go down. We also can sell call option if we expect the security price will go down and vice versa if we sell put option. Usually, option is counted by contract, one contract equivalent to 100 unit options. 1 unit option protects 1 unit share. So, one contract protects 100 unit shares. Before learning how to trade option, terminologies that you need to know are as follow: a)Strike price: Strike price is the price that is agreed by both buyer and seller of the option to deal with. That means if the strike price of the call option is 35, seller of this option obligates to sell security at this price to the buyer of this option even though the market price of the security is higher than 35 if the buyer exercises the option. Buyer of this option can buy a security with a price that is lower than the market price. If the current market price is $39, the buyer will earn $4. If the security price is lower than the strike price, buyer will hold the option and leave the option to expire worthless. For put option strike price, buyer of the option has the right to sell the security at the strike price to the seller of the option. That means if the put option strike price is 30, seller of this option obligates to buy the security at this price from the buyer if he or she exercises the option even though the market price is lower than this price. If the market is $25, the option buyer will earn $5. It looks like a lot of transactions have been involved; but actually, seller of the option will not buy a security and sell it to the buyer. The broker firm will do all the transaction but the extra money that has used to buy the security has to be paid by the seller. This means, if the seller loss $4, the buyer will earn $4. b)Out of the money, in the money and near/at the money option: Option price comprises of time value and intrinsic price.
Time Value + Intrinsic Value = Option Price
Time value is the amount of money that the option worth due to the time the option has until its expiration date. Longer the time the option has until its expiration date, higher the time value of this option. Time value of an option will become zero if the option has expired. Intrinsic value for in the money call option is the difference between current market security price and option strike price. Conversely, in the money put options intrinsic value is the difference between option strike price and current market security price. If the current security price is lower than the call option strike price, this option is an out of the money option. It only has time value. Call option with strike price that is lower than the current market security price is an in the money option. This option has time value and also intrinsic value. Near or at the money option is the option, which strike price is close to the current market security price. c)Delta value: Delta value shows the amount of the option price will change when the security price changes by $1.00. It is a positive value for call option and negative value for put option. It ranges from 0.1 to 1.0. Delta value for in the money option is more than 0.5 and out of the money option is less than 0.5. Delta value for deep in the money option usually is more than 0.9. If the option delta value is 0.6, meaning that when the security price goes up $1, option price will go up $0.60. If the security price goes up $0.10, the option price will goes up $0.06. Usually, $0.06 will round up to $0.10. d)Theta value: Theta value is a negative value, which shows the decay of the option time value. Option, which has longer time to expiry, has lower absolute theta value than option, which has shorter time to expiry. High absolute theta value means the option time value decays more than the low absolute theta value option. A theta value of -0.0188 means that the option will lose $0.0188 in its premium after passage of seven days. Options with a low absolute theta value are more preferable for purchase than those with high absolute theta value. e)Gamma value: Gamma value shows the change of the delta value of an option when the security price increases or decreases. For an example, gamma value of 0.03 indicates that the delta value of this option will increase 0.03 when the security price goes up $1. Option, which has longer time to expiry, has lower value of gamma than option, which has shorter time to expiry. The gamma value also changes significantly when the security price moves near the option strike price. f)Implied volatility: Implied volatility is a theoretical value, which is used to represent the volatility of a security price. It is calculated by substituting actual option price, security price, option strike price and the option expiration date into the Black-Scholes equation. Options with a high volatility stocks are cost more than those with low volatility. This is because high volatility stock option has a greater chance to become in the money option before its expiration date. Most purchasers prefer high volatility stock options than the low volatility stock options.