Cboe Global Markets' options exchange, C1, published a notice saying that effective trade date November 9, 2026 it "will begin to roll out S&P 500 Index (SPX) AM-settled-Weekly options, subject to regulatory review." The underlying is the S&P 500 Index (SPX) and the new trading symbol is SPXO, according to Cboe's notice. Because the rollout is subject to regulatory review, the timetable and details can change. This article only describes what the notice says and explains the mechanics in general terms.

Two Wednesdays Are Listed First: November 18 and December 16

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Cboe said it will initially roll out two weekly expirations, November 18, 2026 and December 16, 2026, chosen to align with the standard monthly VIX settlements. The notice describes the standard monthly VIX settlement as generally the Wednesday 30 days prior to the third Friday of the calendar month immediately following the month in which the standard VIX options and VX futures expire. It adds that additional weekly expirations will be introduced at a future date, and that SPXO expirations were available to test in the C1 Certification environment starting October 5, 2026.

The notice also states a consequence for existing products: SPX options whose expirations coincide with the VIX monthly settlement will now be listed with both AM settlement and PM settlement. On those two Wednesdays the same underlying index will therefore have an opening-settled contract alongside a closing-settled one.

What "AM-Settled" Means Compared With SPX and SPXW

Most index options traders know two settlement styles. Under the notice, SPXO behaves like the existing AM-settled SPX options that expire on the third Friday of the month: it "will expire at the opening of trading on their expiration date and will settle to the SPX opening settlement price (SET)." In plain terms, the final value of an AM-settled contract is based on the opening prints of the index's component stocks that morning, not on the 4:00 p.m. ET close.

Cboe's notice also notes that SPXW, the weekly symbol, sits on a separate matching engine from SPX. Educationally, the usual PM-settled weekly contract is settled off the closing value, so its holder watches the entire final session. An AM-settled contract has no final session at all, which changes the risk in three ways:

  • Overnight gap exposure. According to the notice, on the last trading day before an SPXO series expires, trading in that series stops at 4:00 p.m. and does not resume for that evening's Global Trading Hours (GTH) session. Anything that moves the market after the close, such as news or overseas trading, cannot be hedged in that series before the opening settlement is set.
  • Settlement price risk. The value depends on one opening calculation rather than a day's worth of trading. An option that looked in or out of the money at Tuesday's close can settle differently once Wednesday's opening prices print.
  • No last-day trading. Because the contract ceases trading the prior afternoon, there is no final-day window to roll or close a position.

    • None of this makes one style better. It makes them different, and traders who also hold other index options need to know which settlement a contract uses. Our guide to zero-DTE options covers same-day expiration in general, and the OCC disclosure document describes the risks of standardized options, including index options.

    Under the Hood: Price-Time Allocation and Complex-Order Limits

    The notice lists several operating details for market participants. SPXO will use price-time allocation in the single-leg and complex books, while SPX stays pro-rata. SPXO quotes priced above $0 carry a minimum quote size requirement of 1. SPXO shares matching unit 33 with SPX, and current SPX risk rules apply automatically; trading permit holders can configure separate risk limits for SPXW and SPX but not for SPXO.

    Complex orders are permitted with any combination of options across two of SPX, SPXO and SPXW. However, complex orders can only execute by legging into the single-leg books if all the single-leg books are on the same matching unit, so combinations of SPXW with SPX or SPXO cannot leg in because they sit on separate matching units. SPXO also follows the SPX trading schedule, including participation in GTH. For retail traders, these points mostly matter indirectly through how brokers route and fill multi-leg orders.

    A Settlement Checklist for the Two New Weeklies

    A neutral way to prepare for any new expiration style is to confirm details before trading it, not to assume it behaves like its siblings:

  • Check the symbol: SPXO is AM-settled, while SPXW weeklies are the existing weekly symbol and SPX is the monthly product.
  • Look up the exact expiration date and the final trading time in your broker's chain, which for SPXO ends at 4:00 p.m. the prior trading day per the notice.
  • Confirm whether a given Wednesday offers both AM and PM versions of SPX, and which one an order will route to.
  • Remember that index options are cash-settled, so there is no share delivery, but an opening settlement value can differ from the prior close.
  • Re-check the rollout status, since Cboe said it is subject to regulatory review.

    • This is a description of how a product is structured, not a suggestion to trade it.

    Sources

  • Cboe: Cboe Options to List S&P 500 AM-Settled Expiring Weekly Options (notice)
  • OCC: Characteristics and Risks of Standardized Options

    • *By the OptionsPilot Editorial Team. Published November 8, 2026, 1:30 PM PT. This article is for education only and is not investment advice. Options involve risk and are not suitable for all investors.*