Option Class

What is an option class?

An option class comprises all options of the same type (either all calls or all puts) listed on an exchange for a single underlying security. For example, every listed call option on Apple (AAPL) belongs to the Apple call option class; every put option on Apple belongs to the Apple put option class.

Key takeaways

• An option class groups all calls or all puts for one underlying security.
• An option series is a subset of a class: all options of the same type that share the same expiration date.
• An option chain shows both calls and puts for a given underlying.
• The size and composition of a class depend on market interest, the underlying’s liquidity, and overall market conditions.

Organization: classes, series, and chains

• Option class: all calls (or all puts) for an underlying security.
• Option series: all options within a class that have the same expiration month and year.
• Option chain: the complete listing of both call and put option classes for an underlying, typically presented by strike and expiry.

How option markets work

• Exchange-traded options are standardized, listed by ticker, and traded through brokers that route orders to market makers and exchanges.
• Prices reflect analytics (e.g., theoretical pricing models) but are driven by supply and demand and expressed through bid–ask quotes.
• Over-the-counter and institutional options may be customized and therefore are not always organized into standard classes.
• Trading and clearing are overseen by central clearing organizations; broker-dealer account requirements and approval levels for options trading vary by firm and jurisdiction.

What information is shown for an option class

Platforms typically present:
* Contract name, strike price, expiration
* Bid, ask, last price, last trade time/date
* Volume, open interest
* Percent change and implied volatility
* Advanced analytics (depending on subscription), such as the Greeks (delta, gamma, theta, vega, rho)

Examples

• Highly liquid ETFs and large-cap stocks often have very large option classes with many strikes and expirations (e.g., SPY calls number in the hundreds).
• Smaller or less-traded issuers can have much smaller classes with only a few strikes and a limited set of expirations.

Conclusion

Option classes provide a standardized way to view and trade the universe of calls or puts for a single underlying security. They are broken into series by expiration and combined into option chains for full market visibility. The breadth of a class changes over time with investor interest, liquidity, and market conditions.