Options Fundamentals: Calls, Puts, and Key Parameters

What is an Option?

An option is a financial contract that derives its value from an underlying asset, just like the forwards and futures we've already discussed. The revolutionary concept, however, is the asymmetry it introduces.

• The buyer (or holder) of the option pays a price, known as the premium, to acquire a right.
• The seller (or writer) of the option receives this premium and, in exchange, takes on an obligation to perform if the buyer chooses to exercise their right.

This "right without an obligation" is the feature that makes options so versatile for both speculation and risk management. To build some intuition, let's watch a short video that uses a real-world analogy to explain the concepts of call and put options.

The Four Basic Option Positions

As the video illustrates, there are two fundamental types of options:

1. Call Option: Gives the holder the right to buy an underlying asset at a specified price. You would buy a call if you are bullish, i.e., you expect the asset's price to rise.
2. Put Option: Gives the holder the right to sell an underlying asset at a specified price. You would buy a put if you are bearish, i.e., you expect the asset's price to fall.

Combining these two types with the two sides of the contract (buyer/long and seller/short) gives us four basic positions every options trader must know. The following diagram provides a perfect summary.

Let's break down each quadrant:

• Long Call: You have the right to buy the underlying stock at a predetermined price.
• Short Call: You have the obligation to sell the underlying stock if the long call holder exercises their right.
• Long Put: You have the right to sell the underlying stock at a predetermined price.
• Short Put: You have the obligation to buy the underlying stock if the long put holder exercises their right.

It's critical to be comfortable with the terminology used to describe these positions. The following video segment clarifies the various synonyms used for the buyer and seller.

Key Parameters of an Option Contract

Unlike the customized forward contracts we saw in the last lesson, most options traded by the public (especially on stocks) are standardized, much like futures. This standardization makes them easy to trade on exchanges. The specific terms of a contract are defined by a set of key parameters.

Moneyness: Intrinsic Value and Time Value

An option's value, or premium, can be conceptually broken down into two parts: intrinsic value and time value. The relationship between the underlying asset's current price and the option's strike price determines its moneyness.

An option can be:

• In-the-Money (ITM): The option has intrinsic value. Exercising it would be immediately profitable (before considering the premium paid).
• At-the-Money (ATM): The strike price is equal to the underlying asset's price.
• Out-of-the-Money (OTM): The option has no intrinsic value. Exercising it would result in a loss.

The following reading clearly defines these states and introduces the formulas for intrinsic value, which should feel familiar given your background in mathematics.

As the reading states, the formulas for intrinsic value are:

• Call Intrinsic Value: $\max (0,S_t-X)$
• Put Intrinsic Value: $\max (0,X-S_t)$

Where $S_t$ is the current stock price and $X$ is the strike price.

The following video provides a more conversational walkthrough of these concepts and introduces a very useful mnemonic: "Call Up, Put Down."

American vs. European Options

The final key parameter to understand is the option's exercise style. This defines when the holder can exercise their right.

• American Style: The option can be exercised at any time on or before the expiration date. This offers maximum flexibility to the holder. Most exchange-traded stock options are American style.
• European Style: The option can only be exercised on the expiration date itself. Many index options and options on futures are European style.

This difference in flexibility has a direct impact on the option's premium and the risk faced by the seller. Because an American option gives the holder more rights (i.e., the right of early exercise), it is at least as valuable as, and typically more valuable than, an equivalent European option.

The table below provides a clear summary of the differences.

The following short video clip reinforces this distinction.

Conclusion

In this lesson, we have moved from the world of obligations (forwards and futures) to the world of rights. We have defined the fundamental option contracts and their essential characteristics.

Key Takeaways:

• An option contract gives the buyer (holder) the right, but not the obligation, to buy (a call) or sell (a put) an underlying asset. The seller (writer) receives a premium and takes on an obligation.
• The key parameters of a standardized option are its underlying asset, type (call/put), strike price, expiration date, and contract size (multiplier).
• An option's moneyness (in-the-money, at-the-money, or out-of-the-money) describes the relationship between the stock price and the strike price, and determines its intrinsic value. The premium is the sum of this intrinsic value and its time value.
• American options can be exercised at any point up to expiration, while European options can only be exercised at expiration. This makes American options generally more valuable.

Now that we have a solid grasp of what options are, our next lesson will focus on visualizing their financial outcomes. We will learn to draw and interpret payoff diagrams for calls, puts, and forwards, which provide a powerful graphical tool for understanding the profit and loss potential of these instruments.