Class (of Options)

A "class" of options refers to every listed option — calls and puts, at every strike price and every expiration date — that is based on the same underlying stock, ETF, or index. It's the widest way to group options: not one specific contract, but the entire family of contracts tied to one underlying.

To understand class, it helps to see the layers underneath it. A single option contract is defined by four things: the underlying, whether it's a call (right to buy) or a put (right to sell), the strike price, and the expiration date. A "series" is a narrower group — all contracts with the same underlying, type, strike, AND expiration (for example, all Apple $200 calls expiring the same month). A "class" zooms out from that: it's all the calls and all the puts, at all strikes and all expirations, on Apple. So every option series on Apple belongs to the same class, but many different series exist within it.

The nuance that trips people up is that "class" sounds like it should mean something narrower, like just calls or just puts, but it actually includes both. It also has nothing to do with the exchange the option trades on, or with the option's "style" (American-style, which can be exercised any time before expiration, versus European-style, which can only be exercised at expiration) — those are separate classifications layered on top. Two contracts can be in the same class but differ in strike, expiration, style, or even exercise settlement type.

Traders and exchanges use "class" mostly for structural and regulatory purposes — things like position limits (caps on how many contracts on one underlying a single trader can hold) are often set at the class level, aggregating across all the strikes and expirations you hold on that underlying.