Guide to Options Prices: How are Options Priced?
Editor's Note: Options are not suitable for all investors. Options involve risks, including substantial risk of loss and the possibility an investor may lose the entire amount invested in a short period of time. Please see the Characteristics and Risks of Standardized Options.
Options are derivative financial instruments that give buyers the right (but not the obligation) to buy or sell an underlying security, such as a stock, at a predetermined price (the strike price) within a set time frame. The price of an option, known as the premium, is determined by factors like the underlying asset’s market price, intrinsic value, time until expiration, and volatility.
Understanding how options are priced can help investors decide when to enter or exit a trade, manage risk, or evaluate potential returns.
Key Points
• Option pricing may be based upon factors including market price, intrinsic value, time value, and volatility.
• The Black-Scholes model is used for European options, factoring in stock price, strike price, interest rates, time to expiration, and volatility.
• The binomial model suits U.S. options, valuing an option based on whether the underlying asset’s price moves up or down at each step before expiration.
• The trinomial model extends the binomial model by adding an unchanged price outcome, suitable for complex options.
• Options are high-risk investments that allow traders to seek profit from the price movements of stocks, or to hedge against potential losses.
How is an Option Price Determined?
There are two main types of options: call options and put options. An investor who buys a call option acquires the right to buy the underlying asset at the strike price price, while, conversely, an investor who buys a put option acquires the right to sell the option’s underlying asset at the strike price.
Options traders analysts take many factors into account to determine the price, or premium, of call options and put options. The most widely known method for determining the value of an option is the Black-Scholes model. But other models — such as the binomial and trinomial options pricing models — are more commonly used to determine stock option prices.
All of those options pricing models are complex, but they all draw on a few primary factors that drive the investment value of an options contract:
• The market price of the stock that underlies the option
• The current intrinsic value of the option
• The time until the option expires
• Volatility
Market Price and Intrinsic Value
Market price first is easy to understand — it’s the price at which the underlying stock is trading. The second factor — the intrinsic value of the option — is the value of the option would be worth if sold at that moment. This only applies if the price of the underlying stock has moved to where the option is “in the money,” meaning the owner of the option would make a profit by exercising it.
Recommended: Popular Options Trading Terminology to Know
Time Value
The time until expiration is more complex. This so-called time value reflects the amount of time before expiration of a contract in options trading. It represents the possibility that an out-of-the-money option could eventually become profitable.
It’s the one part of an option’s value that only goes down — and which goes at an increasingly rapid rate as the options contract approaches expiration. As the expiration date approaches, larger price movements in the underlying stock are required to create significant changes in the option’s price.
💡 Quick Tip: Before opening an investment account, know your investment objectives, time horizon, and risk tolerance. These fundamentals will help keep your strategy on track and with the aim of meeting your goals.
Volatility
Time value reflects the potential for price movement from the underlying asset, influenced by factors such as volatility and market expectations of future price fluctuations. As a general rule, stocks with a history of high volatility underlie options with a higher likelihood to be in-the-money at the time of their expiration.
Volatility, in many pricing models, is represented by a measure of price fluctuations of the underlying asset. Beta, on the other hand, measures the asset’s volatility versus the volatility of the overall market. Options on stocks with higher historic or expected volatility typically cost more than options contracts on stocks that have little reputation for dramatic price swings.
Recommended: Understanding The Greeks in Options Trading
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*Check out the OCC Options Disclosure Document.
What Are the Different Option Pricing Models?
There are several models that investors and day traders consider when figuring out how to price an option. Here’s a look at a few of the most common:
The Black-Scholes Merton (BSM) Model
The best-known options pricing method is the Black-Scholes model. The model consists of a mathematical formula that can be daunting for people without a math background. That’s why both institutional and retail investors employ online options calculators and analysis tools.
The economists who created the formula published their findings in 1973, and won the 1997 Nobel Prize in economics for this new method for arriving at the value of financial derivatives.
Also known as the Black-Scholes Merton (BSM) model, the Black-Scholes equation takes the following into account:
• The underlying stock’s price
• The option’s strike price
• Current interest rates
• The option’s time to expiration
• The underlying stock’s volatility
In its pure form, the Black-Scholes model only works for European options, which investors can not exercise until their expiration date. The model doesn’t work for U.S. options, because U.S. options can be exercised before their expiration date.
The Binomial Option Pricing Model
The binomial option pricing model is less well-known outside of financial circles, but it’s more widely used. One reason it’s more popular than the Black-Scholes Model is that it can work for U.S. options. Invented in 1979, the binomial is based on the assumption that, in any pricing scenario, an underlying asset’s price will move either up or down. As a method for calculating an option’s value, the binomial pricing model uses the same basic data inputs, such as the underlying asset’s price, strike price, time to expiration, the interest rate, and volatility, and its equation may be updated as new information emerges.
In comparison with other models, the binomial option pricing model is very simple at first, but it becomes more complex as investors take multiple time periods into account. For a U.S. option, which the owner can exercise at any point before it expires, traders often use the binomial model to decide when to exercise the option.
By using the binomial option pricing model with multiple periods of time, the trader has the advantage of being able to better visualize the change in the price of the underlying asset over time, and then evaluate the option at each point in time. It also allows the trader to update those multi-period equations based on each day’s price movements and emerging market news.
Recommended: What Is a Straddle in Options Trading?
The Trinomial Option Pricing Model
The trinomial option pricing model is similar to the binomial model but it allows for three possible outcomes for an option’s underlying asset within a given period. Its value can go up, go down, or stay the same. As they do with the binomial model, traders recalculate the trinomial pricing model over the course of an option’s life, as the factors that drive the option’s price change, and as new information comes to light.
Its simplicity and acknowledgement of a static price possibility makes it more widely used than the binomial option pricing model. When pricing exotic options, or any complex option with features that make it harder to calculate than the common calls and puts on an exchange, many investors favor the trinomial model as a more stable and accurate way of understanding what the price of the option should be.
The Takeaway
Options pricing isn’t just about a single number — it’s the result of multiple factors, from market price and volatility to the passage of time. Investors rely on models like Black-Scholes, binomial, and trinomial pricing to estimate an option’s value, each offering different insights depending on the type of contract.
Although these calculations can seem complex, the core idea remains the same: an option’s price reflects both current conditions and future possibilities. Understanding these mechanics can help traders make more informed decisions, whether they’re managing risk or seeking new opportunities in the market.
Investors who are ready to try their hand at options trading despite the risks involved, might consider checking out SoFi’s options trading platform offered through SoFi Securities, LLC. The platform’s user-friendly design allows investors to buy put and call options through the mobile app or web platform, and get important metrics like breakeven percentage, maximum profit/loss, and more with the click of a button.
Plus, SoFi offers educational resources — including a step-by-step in-app guide — to help you learn more about options trading. Trading options involves high-risk strategies, and should be undertaken by experienced investors. Currently, investors can not sell options on SoFi Active Invest®.
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Options involve risks, including substantial risk of loss and the possibility an investor may lose the entire amount invested in a short period of time. Before an investor begins trading options they should familiarize themselves with the Characteristics and Risks of Standardized Options . Tax considerations with options transactions are unique, investors should consult with their tax advisor to understand the impact to their taxes.
Disclaimer: The projections or other information regarding the likelihood of various investment outcomes are hypothetical in nature, do not reflect actual investment results, and are not guarantees of future results.
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