Options Chain
An options chain is the displayed grid of listed calls and puts by strike and expiration. OPRA collates quotes from all U.S. options exchanges into the NBBO — not a single-venue print.
An options chain is a quote grid of listed calls and puts by strike and expiration. OPRA collates exchange prices into the National Best Bid and Offer. Bid is the highest price a buyer will pay. Ask is the best price a seller will accept. Bid/ask size is aggregate contracts, not open interest or volume.
The Options Industry Council (OIC, August 2024) states that data in a typical option chain is constructed by Options Price Reporting Authority, LLC (OPRA) by collating prices from all options exchanges into the best bid and offer, also known as the National Best Bid and Offer (NBBO). Read the chain as a quote surface. Do not treat a cell as a fill, and do not invent open interest or volume from this page.
Calls and puts by strike and expiration
A listed equity option is a standardized contract. A call is the right to buy the underlying; a put is the right to sell it. The chain quotes those rights: expirations down the calendar, strikes down the ladder, calls on one wing and puts on the other. Weekly and monthly series can sit on the same name. The grid is the map. It is not the trade. Contract specs live in Stock Options Fundamentals. Greeks and model value are a different lesson. Implied volatility is read off this grid. This page does not invent an IV, an open-interest figure, or a volume figure.
OPRA collates the NBBO — not one venue print
U.S. listed options trade on multiple exchanges. OIC’s process: a participant sends a market order or a limit order to a brokerage firm; the firm routes to an exchange; the exchange sorts by class, series, bids, offers, and desired price. The order can execute, rest in a price queue, or improve the bid or the offer and be displayed in the option chain.
OPRA collates those displayed prices from all options exchanges into the NBBO. The National Best Bid is the highest bid across participating venues; the National Best Offer is the lowest offer. That pair is the inside the chain is showing. It is a consolidated best, not a single-book last sale. Do not read a last print as the NBBO. Depth behind the inside is a different object — Level 2 quotes on the equity, or exchange depth on the option.
Bid, ask, and size as displayed
OIC takeaways are the working definitions. On a chain, the bid is the highest price an investor is willing to pay, and the ask is the best price at which an investor is willing to sell. Bid size and ask size are an aggregate number of option contracts available at those prices. That aggregate is not open interest and not daily volume. This page invents neither figure. If bid size is greater than ask size, OIC notes that may indicate demand to buy exceeds supply to sell. That is a qualitative tell, not a forecast.
The width between bid and ask is as notable as the prices. That width is the bid-ask spread. A marketable buy typically meets the ask; a marketable sell typically meets the bid. A limit can sit inside and may not fill. This page does not invent spread cents. OIC lists factors that can widen or narrow option spreads — economic events, anticipated news such as an earnings announcement, perceived trading risk, competition among participants, and the underlying’s own spread — without a universal penny figure.
Chain fields (legend only)
Not a live quote. No open interest, no volume, no implied-volatility level.
| Field | What the chain is showing | What it is not |
|---|---|---|
| Expiration | Series date for that row of calls and puts | A session clock or a fill |
| Strike | Contract exercise price | A target or a forecast |
| Call / put | Right to buy / right to sell the underlying | Stock until exercise or assignment |
| Bid / ask | NBBO inside as collated by OPRA | A last sale, a mid you are owed, or a fill |
| Bid size / ask size | Aggregate contracts displayed at those prices (OIC) | Open interest or daily volume |
Index GTH is not C1 equity-options GTH
Do not mix product clocks. Cboe C1 index-options Global Trading Hours for named products is a different board from the equity tape and from single-stock options. Cboe C1 equity-options GTH (select multi-listed single-stock options) is TBA (notice C2026081001). Do not write as if those names already trade in that morning window. The cash equity session map — early 4:00 a.m. versus 7:00 a.m. exchange split, RTH, late, overnight planned December 6, 2026, not live — lives on U.S. stock market session hours 2026. Broker overnight is ATS access, not exchange overnight, and not options GTH.
What this page is not
Not a live chain, not a scanner, and not a source of invented open interest, volume, or IV rank. Not a squeeze page. Not C1 equity-options GTH treated as live. Not a claim that a mid-market price is a fill. Size the underlying with dollar risk: example only, $10,000 account, 1% risk, $1.50 stop distance → 66 shares, round down. The risk calculator is a crypto UI; treat the unit as shares, round down.
FAQ
Is the options chain a single-exchange quote?
No. OIC: a typical option chain is constructed by OPRA by collating prices from all options exchanges into the NBBO. The inside is a national best, not one venue’s print.
Do bid size and ask size equal open interest?
No. OIC treats bid size and ask size as the aggregate contracts displayed at those prices. Open interest is outstanding contracts. This page invents neither figure. Do not swap the labels.
Does a displayed bid or ask guarantee a fill?
No. Displayed interest can cancel or update, or be smaller than your order. A marketable order can slip. A limit may never trade.
Do single-stock options trade in C1 Global Trading Hours?
Not as a live fact here. C1 equity-options GTH is TBA (C2026081001). Do not mix that clock with index-options GTH or with the cash equity tape.
Where do implied volatility and the spread live on the chain?
IV is a model output from the option’s price, taught on the implied-volatility glossary page. The bid-ask spread is ask minus bid on that same row. Neither is a number this page invents.
Educational only. Not financial, tax, or legal advice. Chain construction follows OIC (August 2024) on OPRA and the NBBO. Session clocks can change. Unknowns are marked TODO:VERIFY. Trading stocks and listed options can result in loss of capital.