# Stock options calls and puts

In order to protect the put buyer from default, the put writer is required to post margin. The put buyer does not need to post margin because the buyer would not exercise the option if it had a negative payoff. A buyer thinks the price of a stock will decrease. He pays a premium which he will never get back, unless it is sold before it expires. The buyer has the right to sell the stock at the strike price. The writer receives a premium from the buyer.

If the buyer exercises his option, the writer will buy the stock at the strike price. If the buyer does not exercise his option, the writer's profit is the premium. A put option is said to have intrinsic value when the underlying instrument has a spot price S below the option's strike price K. Upon exercise, a put option is valued at K-S if it is " in-the-money ", otherwise its value is zero.

Prior to exercise, an option has time value apart from its intrinsic value. The following factors reduce the time value of a put option: Option pricing is a central problem of financial mathematics. Trading options involves a constant monitoring of the option value, which is affected by changes in the base asset price, volatility and time decay. Moreover, the dependence of the put option value to those factors is not linear — which makes the analysis even more complex. The graphs clearly shows the non-linear dependence of the option value to the base asset price.

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Unsourced material may be challenged and removed. November Learn how and when to remove this template message. The price of the call contract must reflect the "likelihood" or chance of the call finishing in-the-money.

The call contract price generally will be higher when the contract has more time to expire except in cases when a significant dividend is present and when the underlying financial instrument shows more volatility. Determining this value is one of the central functions of financial mathematics. The most common method used is the Black—Scholes formula. Importantly, the Black-Scholes formula provides an estimate of the price of European-style options.

Adjustment to Call Option: When a call option is in-the-money i. Some of them are as follows:. Similarly if the buyer is making loss on his position i. Trading options involves a constant monitoring of the option value, which is affected by the following factors:.

The price of the call contract must reflect the "likelihood" or chance of the call finishing in-the-money. The call contract price generally will be higher when the contract has more time to expire except in cases when a significant dividend is present and when the underlying financial instrument shows more volatility.

Determining this value is one of the central functions of financial mathematics. The most common method used is the Black—Scholes formula. Importantly, the Black-Scholes formula provides an estimate of the price of European-style options.

Adjustment to Call Option: When a call option is in-the-money i. Some of them are as follows:. Similarly if the buyer is making loss on his position i. Trading options involves a constant monitoring of the option value, which is affected by the following factors:.