Cboe has filed a proposed rule change with the SEC that would expand where A.M.-settled SPX options can appear on the calendar. This is not a launch announcement and, as of May 19, 2026, it should be treated as pending rulemaking-useful for understanding market structure, but not something traders can assume is live yet.
What Happened
In SEC Release No. 34-105320 (File No. SR-CBOE-2026-044), Cboe proposes to amend its rules to permit listing A.M.-settled SPX options that expire:
- On any Monday through Friday, excluding the third Friday of the month and days that coincide with an end-of-month expiration; and
- On the last trading day of the month (end-of-month expirations), also A.M.-settled.
The key framing is additive: the filing explicitly indicates no change to the existing lineup of P.M.-settled SPX weekly and end-of-month expirations (often referred to as SPXW weeklies in trader shorthand). In other words, the proposal is about adding more A.M. settlement choices, not removing the established P.M. settlement menu that many short-dated traders already use.
The filing was dated April 28, 2026 in the SEC notice, and the notice of filing was published in the Federal Register on May 1, 2026, with a comment deadline set for May 22, 2026.
How A.M. Settlement Actually Works (SET / SOQ)
To understand why this matters, it helps to be precise about what “A.M.-settled” means for SPX.
For standard A.M.-settled SPX expirations, the exercise settlement value is based on a special opening quotation (SOQ) for the S&P 500 Index. Cboe publishes the resulting exercise settlement value under the symbol SET.
Two practical points traders often miss:
- SET is not simply “SPX at 9:30 a.m.” The SOQ is derived from the official opening prices of the S&P 500’s constituent stocks in their primary listings. That means SET can differ from whatever headline SPX print you see at (or shortly after) the open.
- SET is not anchored to a single timestamp. The SOQ is not calculated until all component stocks have opened and their official opening prices are established. On a normal day this can be quick; on a volatile day or a day with opening imbalances, it can take longer-so “A.M.-settled” is more like “opening-auction-based” than “9:30-on-the-dot.”
This isn’t a minor nuance. If the proposed rule change is eventually approved, it would spread those opening-print settlement mechanics beyond the familiar third-Friday A.M.-settled SPX structure and into more everyday dates on the weekly calendar.
Why This Matters For Options Traders
1) It adds a second settlement clock to more dates
Today, many traders mentally map “expiration date” to “risk ends at the close.” That’s a decent shorthand for P.M.-settled expirations, but it breaks down when an A.M.-settled contract shares the same calendar date.
If A.M.-settled weekday SPX expirations become listable, then “same day” could mean two different things:
- Risk that resolves at (or shortly after) the open, via SET; and
- Risk that resolves at the close, via a P.M.-settled series.
That creates a cleaner, listed way to separate overnight-to-open risk from post-open intraday risk. It also makes it easier for market participants to express (or hedge) timing-specific exposures without having to approximate them using adjacent expirations.
2) It can change how traders interpret short-dated pricing
Short-dated index options are often discussed using “expected move” language. But the expected move implied by option prices is always conditional on what time window the contract is really referencing.
On a day with a major pre-market catalyst (macro data, geopolitical headlines, large overnight moves in constituents), an A.M.-settled contract and a P.M.-settled contract with the same calendar date can embed very different distributions:
- The A.M.-settled version concentrates on the overnight gap + opening auction outcome.
- The P.M.-settled version spans the full trading session, including the post-open drift, intraday reversals, and the close.
If both series were available on many dates, it would likely make “implied move comparisons” more nuanced. Traders who compare premiums across expirations without noticing the settlement convention can easily misread what the market is pricing.
3) Same-date A.M. vs P.M. spreads become a more natural market-structure trade
Cboe’s filing highlights spread opportunities that exist when two expirations share a calendar date but settle at different times. Conceptually, a same-date A.M. vs P.M. spread is less about classic term structure (“one week vs the next week”) and more about a settlement-basis distinction (“open window vs full-session window”).
That matters for how the options surface can be used as a timing tool. But it also means more contracts, more symbols on a quote screen, and more ways for people to mismatch what they intended to trade.
4) It raises the “complexity tax” question in an already crowded chain
SPX is already a deep and active ecosystem, especially in very short-dated options. Adding a parallel A.M.-settled schedule across the weekdays could improve precision for some users, but it also risks:
- Fragmenting liquidity across more series (at least initially);
- Creating more opportunities for retail confusion (A.M. vs P.M. on the same date);
- Increasing operational mistakes around exercise decisions and settlement expectations on A.M. expirations.
The net effect likely depends on adoption. If professional users migrate quickly and market makers price both regimes competitively, the market may digest it smoothly. If adoption is uneven, the early phase could feature wider spreads and noisier signals-especially around the open, where conditions can be less liquid and more jumpy.
What Traders May Misunderstand
- “This creates weekday SPX expirations for the first time.” Not exactly. SPX already has a broad menu of P.M.-settled weekday and end-of-month expirations. The proposed change is about introducing A.M.-settled versions on more dates.
- “It’s approved because there’s an SEC release number.” A release number can be attached to a notice of filing. Until there is an SEC approval order (or an effective date under the applicable process), traders should treat the change as proposed, not live.
- “A.M.-settled means it settles to whatever SPX prints at 9:30.” For SPX, A.M. settlement is tied to SET, which is derived from the official opening prices of constituent stocks and can diverge from a simple headline index print at the open.
- “European-style and cash settlement mean expiration is ‘safe’.” SPX’s European exercise style reduces classic early-assignment mechanics seen in equity/ETF options, but it does not remove risk. Opening-print settlement introduces settlement-value uncertainty and exercise-timing considerations.
- “This changes the VIX calculation.” Nothing in this filing implies a VIX methodology change. It’s about what expirations can be listed and how they settle, not about how VIX is computed.
- “Same-date A.M. and P.M. options are interchangeable.” They can share a date and strike but still reference different risk windows and different settlement mechanics. Treat them as distinct instruments.
Important Notes (Not Advice + Options Risk)
This article is for general market-structure education only and is not financial advice, investment advice, or a recommendation to buy or sell any security or strategy. Options trading involves risk and is not suitable for all investors.
Options trading can involve the risk of losing more than the premium paid (or realizing large losses on short options). 0DTE and short-dated index options can be especially risky due to high gamma exposure, rapid P/L changes, and gap risk.
For background on exercise style and cash settlement (which matters for SPX), see Cash-Settled vs. Physically Settled Options Explained and American vs. European Options: Key Differences.
For A.M.-settled index options in particular, the final settlement value (SET) may not be known immediately at the open. Exercise and risk-management decisions can be time-sensitive, and brokerage policies can differ. Consider reviewing your broker’s exercise procedures and the relevant exchange/OCC materials before trading products that settle on the opening process.
Sources
https://www.sec.gov/files/rules/sro/cboe/2026/34-105320.pdfhttps://cdn.cboe.com/resources/regulation/rule_filings/pending/2026/SR-CBOE-2026-044.pdfhttps://cdn.cboe.com/resources/spx/Settlement_of_Standard_AM_Settled_SP_500_Index_Options.pdfhttps://regulations.justia.com/regulations/fedreg/2026/05/01/2026-08471.htmlhttps://ww2.cboe.com/tradable_products/vix/vix_futures/specifications/
