What is Delta in Options Trading?
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.
In options trading, delta measures the sensitivity of an option’s price relative to changes in the price of its underlying asset. Delta is a risk metric that compares changes in a derivative’s underlying asset price to the change in the price of the derivative itself.
In short, delta measures the sensitivity of a derivative’s price to a change in the underlying asset. Using delta as part of an option’s assessment may help investors make better trades.
Key Points
• Delta measures how option prices change in response to the underlying asset’s price.
• Call options have a delta between 0 and 1; put options have a delta between 0 and -1.
• Higher absolute delta values indicate greater price sensitivity.
• Delta-neutral strategies balance portfolios by offsetting price movements.
• Delta offers a probabilistic estimate of price movement, not a guaranteed outcome.
What Is Delta?
Delta is one of “the Greeks,” a set of trading tools denoted by Greek letters. Some in options trading refer to the Greeks as risk sensitivities, risk measures, or hedge parameters. The delta metric is a commonly used Greek for measuring risk; the other four are gamma, theta, vega, and rho.
Delta Example
For each $1 that an underlying stock moves, the derivative’s price changes by the delta amount. Investors typically express delta as a decimal value or percentage. For example, let’s say there is a long call option with a delta of 0.40. If the option’s underlying asset increased in price by $1.00, the option price would increase by $0.40.
Because delta changes alongside underlying asset changes, the option’s price sensitivity also shifts over time. Various factors impact delta, including asset volatility, asset price, and time until expiration.
For call options, delta increases toward 1.0 as the underlying asset price rises. For put options, delta moves toward -1.0 as the underlying asset’s price falls.
Recommended: A Beginner’s Guide to Options Trading
How Is Delta Calculated?
Analysts calculate delta using the following formula with theoretical pricing models:
Δ = ∂V / ∂S
Where:
• ∂ = the first derivative
• V = the option’s price (theoretical value)
• S = the underlying asset’s price
The formula Δ = ∂V / ∂S represents how small changes in the underlying price (S) affects the option’s value (V).
Some analysts may calculate delta with the more complex Black-Scholes model that incorporates additional factors. This model is a widely used theoretical pricing model that factors in volatility, time decay, and interest rates to estimate an investment’s delta. Traders generally don’t calculate the formula themselves, as trading software and exchanges do it automatically.
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How to Interpret Delta
Delta is a ratio that compares changes in the price of derivatives and their underlying assets. The direction of price movements will determine whether the ratio is positive or negative.
Bullish options strategies have a positive delta, and bearish strategies have a negative delta. It’s important to remember that unlike stocks, buying or selling options does not necessarily indicate a bullish or bearish strategy.
Traders use delta to gain an understanding of whether an option will expire in the money or not. The more an option is in the money, the further the delta value will deviate from 0, towards either 1 or -1.
The more an option goes out of the money, the closer the delta value gets to 0. Higher delta means higher sensitivity. An option with a 0.9 delta, for example, will change more if the underlying asset price changes than an option with a 0.10 delta. If an option is at the money, the underlying asset price is the same as the strike price, so there is a 50% chance that the option will expire in the money or out of the money.
Recommended: Differences Between Options and Stocks
Calls: Long and Short
For call options, delta is positive, indicating that the option’s price will increase as the underlying asset increases. Delta’s value for calls range from 0 to 1. When a call option is at the money (i.e. the asset price equals the strike price), the delta is near 0.50, meaning it has an equal probability of being out-of-money or in-the-money. As the underlying asset’s price increases, delta moves closer to 1. This signals that the option has demonstrated a high price sensitivity.
• For long call positions, delta increases toward 1 as the underlying asset’s price rises, signaling greater price sensitivity.
• For short call positions, delta is negative, meaning the position loses value as the asset price increases
Puts: Long and Short
For put options, delta is negative, indicating that the option’s price will increase when the underlying asset’s price decreases. Delta’s value for puts ranges from 0 to -1. As with call options, when a put option is at the money, the delta is near -0.50, representing an equal probability that the put could expire in or out of the money. If an underlying asset’s price decreases, the delta would move closer to -1, which would indicate an option has high price sensitivity to price changes in its underlying asset.
• For long put positions, delta moves closer to -1 as the underlying asset’s price decreases, indicating greater price sensitivity.
• For short put positions, delta is positive, meaning the position loses value as the asset price declines.
How Traders Use Delta
In addition to assessing option sensitivity, traders look to delta as a probability that an option will end up in or out of the money.
Every investor has their own risk tolerance, so some might be more willing to take on a risky investment if it has a greater potential reward. When considering Delta, traders recognize that the closer it is to 1 or -1, the greater the option’s sensitivity is to movements in the underlying asset.
If a long call has a Delta of 0.40, traders often interpret this as a 40% chance of expiring in the money. So if a long call option has a strike price of $30, the owner has the right to buy the stock for $30 before the expiration date. There is believed to be a 40% chance that the stock’s price will increase to at least $30 before the option contract expires. These outcomes are not guaranteed, however.
Traders also use Delta to put together options spread strategies.
Delta Neutral
Traders may also use Delta to hedge against risk. One common options trading strategy, known as Delta neutral, is to hold several options with a collective Delta near 0.
The strategy reduces the risk of the overall portfolio of options. If the underlying asset price moves, it will have a smaller impact on the total portfolio of options than if a trader only held one or two options.
One example of this is a calendar spread strategy, in which traders use options with various expiration dates in order to get to Delta neutral.
Delta Spread
With a delta spread strategy, traders buy and sell various options to create a portfolio that offsets so the overall delta is near zero. With this strategy the trader hopes to make a small profit off of some of the options in the portfolio.
Using Delta Along With Other Greeks
Delta measures an option’s directional exposure. It is just one of the Greek measurement tools that traders use to assess options. There are five Greeks that work together to give traders a comprehensive understanding of an option. The Greeks are:
• Delta (Δ): Measures the sensitivity between an option price and the price of the underlying security.
• Gamma (Γ): Measures the rate at which delta is changing.
• Theta (θ): Measures the time decay of an option. Options become less valuable as the expiration date gets closer.
• Vega (υ): Measures how much implied volatility affects an option’s value. Higher implied volatility generally leads to higher option premiums.
• Rho (ρ): Measures an option’s sensitivity to changing interest rates. Rho is most suited for long-dated options because changes in interest rates have a larger effect on their value.
The Takeaway
Delta provides an estimate of how much the price of an option may change relative to a $1 change in the price of its underlying security. Delta is a useful metric for traders evaluating options and can help investors determine their options strategy. Traders often combine it with other tools and ratios during technical analysis.
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®.
FAQ
What does a 10 delta option mean? Or a 30 delta option?
A 10 delta option means the option’s price is expected to change by $0.10 for every $1.00 change in the underlying asset’s price. A 30 delta option would change by $0.30 for the same price movement.
What is the ideal delta for a covered call?
The ideal delta for a covered call is typically between 0.30 and 0.40. This range balances earning a decent premium while minimizing the risk of the call being exercised too quickly.
Do you want high or low delta options?
It depends on your strategy. High delta options are more sensitive to price changes in the underlying asset and are closer to being in the money. Low delta options are less sensitive but cost less and are generally further out of the money.
How accurate is delta in options trading?
Delta is an estimate, not a guarantee. It’s generally accurate for small price changes in the underlying asset, but may become less reliable for larger movements since delta itself changes over time (as it’s influenced by gamma).
Why is delta negative for put options?
Delta is negative for put options because their value increases as the underlying asset’s price decreases. The negative delta reflects this inverse relationship.
Does delta increase with volatility?
Not directly. Delta measures price sensitivity, while volatility impacts vega (which reflects changes in option prices due to implied volatility). Higher volatility can push options further in or out of the money, however, indirectly influencing delta.
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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.
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