Self-Regulatory Organizations; Cboe EDGX Exchange, Inc.; Notice of Filing of a Proposed Rule Change To Amend Its Rules To Enable the Exchange To Offer Trading in Equity Securities and Exchange Traded Products 23 Hours per Day, Five Days per Week

SECURITIES AND EXCHANGE COMMISSION [Release No. 34-105206; File No. SR-CboeEDGX-2026-019] Self-Regulatory Organizations; Cboe EDGX Exchange, Inc.; Notice of Filing of a Proposed Rule Change To Amend Its Rules To Enable the Exchange To Offer Trading in Equity Securities and Exchange Traded Products 23 Hours per Day, Five Days per Week April 10, 2026. Pursuant to Section 19(b)(1) of the Securities Exchange Act of 1934 (the “Act”), 1 and Rule 19b-4 thereunder, 2 notice is hereby given that on March 31, 2026, Cboe EDGX Exchange, Inc. (the “Exchange” or “EDGX”) filed with the Securities and Exchange Commission (the “Commission”) the proposed rule change as described in Items I, II, and III below, which Items have been prepared by the Exchange. The Commission is publishing this notice to solicit comments on the proposed rule change from interested persons. 1  15 U.S.C. 78s(b)(1). 2  17 CFR 240.19b-4. I. Self-Regulatory Organization's Statement of the Terms of Substance of the Proposed Rule Change Cboe EDGX Exchange, Inc. (the “Exchange” or “EDGX”) proposes to amend its rules to enable the Exchange to offer trading in equity securities and exchange traded products 23 hours per day, five days per week. The text of the proposed rule change is in Exhibit 5. The text of the proposed rule change is also available on the Commission's website ( https://www.sec.gov/rules/sro.shtml ), the Exchange's website ( https://www.cboe.com/us/equities/regulation/rule_filings/edgx/ ), and at the principal office of the Exchange. II. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Change In its filing with the Commission, the Exchange included statements concerning the purpose of and basis for the proposed rule change and discussed any comments it received on the proposed rule change. The text of these statements may be examined at the places specified in Item IV below. The Exchange has prepared summaries, set forth in sections A, B, and C below, of the most significant aspects of such statements. A. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Change 1. Purpose The Exchange proposes to amend its rules to permit the trading of equity securities and Derivative Securities  3 on the Exchange 23 hours per day, five days per week (“23x5 Trading”). 4 3   See Exchange Rule 1.5(ff). 4  The Exchange initially submitted the proposed rule change on March 13, 2026 (SR-CboeEDGX-2026-013). On March 24, 2026, the Exchange withdrew that filing and on March 31, 2026, the Exchange submitted this proposal. Background The Exchange's proposal to offer 23x5 Trading is driven both by the growth in the volume during the Exchange's existing Early Trading Session, as well as the growing demand for access to the U.S. markets, particularly by retail investors in the Asia Pacific (“APAC”) region. The Exchange has consistently heard from APAC broker-dealers that their retail investors—particularly those in Hong Kong, Japan, Korea, Singapore, and Australia—want greater access to the U.S. equities market and that they desire trusted venues that offer transparency, robust liquidity, and efficient price discovery. 5 5   See “What Does it Take to Offer Around the Clock Equities Trading?”—Cboe Insights, February 2, 2025, available at: https://www.cboe.com/insights/posts/what-does-it-take-to-offer-around-the-clock-equities-trading/. The average daily volume (“ADV”) during the Early Trading Session  6 across Cboe's U.S. equities exchanges increased 110% from January 2023 to February 2026, and increased 404% between January 2022 and February 2026. 7 Cboe's U.S. equities exchanges have also increased their market share during the Early Trading Session since 2022, with Early Trading Session ADV increasing 258% 8 between January 2023 and February 2026 alone. 9 The Exchange believes that 23x5 Trading will further benefit investors and the national market system by increasing market accessibility, promoting capital formation, and facilitating portfolio management. 6   See Exchange Rule 1.5(jj). 7  Source: Internal Cboe Data. 8  Cboe's market share for the Early Trading Session ( i.e., 4:00 to 7:00 a.m.) trading increased by 305 basis points (“bps”) from January 2023 to February 2026. Source: Internal Cboe Data. 9  Market share increased 33 bps from January 2022 to February 2026. Looking at the full year 2022 against the full year 2025, market share increased 336 bps. Source: Internal Cboe Data. Currently, Users  10 may enter orders into the System  11 from 2:30 a.m. to 8:00 p.m. Eastern Time (“ET”). 12 The Exchange currently offers five trading sessions on each day it is open for trading: (1) the Early Trading Session  13 (4:00 a.m. to 8:00 a.m.); (2) the Pre-Opening Session  14 (8:00 a.m. to 9:30 a.m.); (3) the Regular Session  15 (the time between the completion of the Opening Process or Contingent Open, as defined in Rule 11.7, and 4:00 p.m.); (4) Regular Trading Hours  16 (9:30 a.m. to 4:00 p.m.); and (5) the Post-Closing Session  17 (4:00 p.m. to 8:00 p.m.). During each session, orders may be entered, executed, or routed away. 18 10  The term “User” shall mean any Member or Sponsored Participant who is authorized to obtain access to the System pursuant to Rule 11.3. See Rule 1.5(ee). 11  The term “System” shall mean the electronic communications and trading facility designated by the Board through which securities orders of Users are consolidated for ranking, execution and, when applicable, routing away. See Rule 1.5(cc). 12   See Exchange Rule 11.1(a). All times stated herein are in ET. 13   See Rule 1.5(jj). 14   See Rule 1.5(s). 15   See Rule 1.5(ii). 16  The term Regular Trading Hours” means the time between 9:30 a.m. and 4:00 p.m. Eastern Time. See Rule 1.5(y). 17   See Rule 1.5(r). 18   See Exchange Rule 11.1(a). Under current Rule 11.1(a)(1), the Exchange will not accept the following orders prior to 4:00 a.m., or prior to 7:00 a.m. for orders eligible for a “7:00 a.m. Start”:  19 19  An order designated as eligible for execution during the Early Trading Session beginning at 7:00 a.m. is referred to as a “7:00 a.m. Start.” • orders with a Post Only  20 instruction; 20  “Post Only Orders” refers to an instruction that may be attached to an order that is to be ranked and executed on the Exchange pursuant to Rule 11.9 and Rule 11.10(a)(4) or cancelled, as appropriate, without routing away to another trading center except that the order will not remove liquidity from the EDGX Book, except as described below. An order with a Post Only instruction will remove contra-side liquidity from the EDGX Book if the order is an order to buy or sell a security priced below $1.00 or if the value of such execution when removing liquidity equals or exceeds the value of such execution if the order instead posted to the EDGX Book and subsequently provided liquidity, including the applicable fees charged or rebates provided. To determine at the time of a potential execution whether the value of such execution when removing liquidity equals or exceeds the value of such execution if the order instead posted to the EDGX Book and subsequently provided liquidity, the Exchange will use the highest possible rebate paid and highest possible fee charged for such executions on the Exchange. See Exchange Rule 11.6(n)(4). • intermarket sweep orders (“ISOs”);  21 21  “Intermarket Sweep Orders” or “ISO” are orders The System will accept ISOs (as such term is defined in Regulation NMS). To be eligible for treatment as an ISO, the order must be: (i) a Limit Order; (ii) marked “ISO”; and (iii) the User entering the order must simultaneously route one or more additional Limit Orders marked “ISO,” if necessary, to away Trading Centers to execute against the full displayed size of any Protected Quotation for the security with a price that is superior to the limit price of the ISO entered in the System. Such orders, if they meet the requirements of the foregoing sentence, may be executed at one or multiple price levels in the System without regard to Protected Quotations at away Trading Centers consistent with Regulation NMS ( i.e., may trade through such quotations). See Exchange Rule 11.8(c). • Market Orders  22 other than those with a time-in-force- (“TIF”)  23 instruction of Regular Hours Only (“RHO”)  24 or a Stop Price;  25 22  “Market Orders” are orders to buy or sell a stated amount of a security that is to be executed at the NBBO or better when the order reaches the Exchange. See Exchange Rule 11.8(c). 23  The term “Time in Force” means the period of time that the System will hold an order. See Rule 2.1(f). 24  The term “Regular Hours Only” (“RHO”) means an instruction a User may attach to an order designating it for execution only during Regular Trading Hours, which includes the Opening Process and Re-Opening Process following a halt suspension or pause. See Rule 11.6(q)(6). 25  An order may include a “Stop Price” which will convert the order into a Market Order when the Stop Price is triggered. An order to buy converts to a Market Order when the consolidated last sale in the security occurs at, or above, the specified Stop Price. An order to sell converts into a Market Order when the consolidated last sale in the security occurs at, or below, the specified Stop Price. See Rule 11.8(a)(1). • orders with a Minimum Execution Quantity  26 instruction that also include a TIF instruction of RHO, and all orders with a TIF instruction of Immediate-or-Cancel (“IOC”)  27 or Fill-or-kill (“FOK”). 28 26  “Minimum Execution Quantity” is an instruction a User may attach to an order with a Non-Displayed instruction or a Time-in-Force of Immediate-or-Cancel requiring the System to execute the order only to the extent that a minimum quantity can be satisfied. See Rule 11.6(h) 27  “Immediate Or Cancel” or “IOC” refers to an instruction the User may attach to an order stating the order is to be executed in whole or in part as soon as such order is received. The portion not executed immediately on the Exchange or another trading center is treated as cancelled and is not posted to the EDGX Book. An order with an IOC instruction that does not include a Book Only instruction and that cannot be executed in accordance with Rule 11.10(a)(4) on the System when reaching the Exchange will be eligible for routing away pursuant to Rule 11.11. See Rule 11.6(q)(1). 28  “Fill-or-Kill” or “FOK” refers to an instruction the User may attach to an order stating that the order is to be executed in its entirety as soon as it is received and, if not so executed, cancelled. An order with a FOK instruction is not eligible for routing away pursuant to Rule 11.11. See Rule 11.6(q)(3). Certain order types are also subject to session-specific restriction. For example, orders with a Post Only instruction and ISOs are not accepted for queueing during the Pre-Opening Session if designated with a TIF instruction of RHO. To accommodate 23x5 Trading, the Exchange proposes to extend the order entry window and introduce a new Overnight Trading Session, along with conforming amendments to its session-specific order handling rules, as described below. Proposal The Exchange proposes to amend its rules to enable 23x5 Trading by expanding the Pre-Opening Session and replacing the Early Trading Session with a new Overnight Trading Session. Definitions The Exchange proposes to amend and adopt certain definitions provided in Exchange Rule 1.5. First, the Exchange proposes to expand the Pre-Opening Session under Rule 1.5(s) from 8:00 a.m. to 4:00 a.m., covering the period from 4:00 a.m. to 9:30 a.m. Because this expansion absorbs the period currently covered by the Early Trading Session under Rule 1.5(jj), the Exchange also proposes to delete the “Early Trading Session” definition and replace it with a new defined term, “Overnight Trading Session.” As proposed, the Overnight Trading Session shall mean the time between 9:00 p.m. on any night preceding a business day  29 and 4:00 a.m. on the following calendar day. Rather than defining the Overnight Trading Session by reference to specific calendar days of the week ( e.g., Sunday through Thursday), the proposed definition is anchored to the concept of a “night preceding a business day.” This approach provides that the Overnight Trading Session is triggered by the existence of an upcoming trading day rather than by enumeration of calendar days, providing a more durable and flexible framework that is consistent with the Exchange's proposed Order Acceptance Queueing Time definition in proposed Rule 1.5(kk), as discussed below, and that accommodates changes to the Exchange's trading calendar (including holidays and other non-business days) without requiring conforming amendments to the session definition itself. For example, when a holiday falls on a Monday, there is no night preceding a business day on the prior Sunday and therefore no Overnight Trading Session will commence that Sunday evening, consistent with the Exchange's proposed holiday schedule under Rule 11.1(b). As discussed further below under “Contingency on Industry Readiness,” the Exchange shall not commence operation of the Overnight Trading Session until specified Equity Data Plan readiness conditions have been satisfied. The proposed term would provide “Overnight Trading Session” shall mean the time between 9:00 p.m. on any night preceding a business day, as provided in Rule 11.1(b), and 4:00 a.m. Eastern Time on the following calendar day. For the avoidance of doubt, notwithstanding anything to the contrary in these Rules, the Exchange shall not commence operation of the Overnight Trading Session unless the Equity Data Plans (1) have established a mechanism to collect, consolidate, process and disseminate quotation and transaction information at all times during the Overnight Trading Session that is equivalent to the mechanism established for Exchange trading hours during Regular Trading Hours, and (2) have provided the Exchange with notification that they are prepared to collect, consolidate, process and disseminate quotation and transaction information to accommodate the Overnight Trading Session. Prior to commencing operation during the Overnight Trading Session, the Exchange will file a proposed rule change pursuant to Section 19(b) of the Exchange Act and the rules thereunder to amend its rules confirming that the Exchange is able to comply with its obligations under the Exchange Act and the rules thereunder during the Overnight Trading Session and that such Equity Data Plans are prepared to collect, consolidate, process and disseminate quotation and transaction information at all times during the Overnight Trading Session (“Overnight Trading Session Proposed Rule Change”). If the Overnight Trading Session Proposed Rule Change is not filed within 18 months of the SEC's approval of this proposed rule change, the Exchange will promptly file a proposed rule change to remove the rules that apply to the Overnight Trading Session. 29   See proposed Rule 11.1(b). A business day is any day the Exchange is open for trading, which includes any Monday, Tuesday, Wednesday, Thursday, and Friday, other than a holiday listed below, and shall be deemed to begin at 9:00 p.m. on the preceding calendar day. Second, proposed Rule 1.5(kk) would define “Order Acceptance Queueing Time” to mean 8:55 p.m., the time at which orders may be entered into the System on each night preceding a business day as specified in Rule 11.1(b). The Order Acceptance Queueing Time marks the point at which the System begins accepting orders each night in advance of the Overnight Trading Session. Orders entered during the Order Acceptance Queueing Time will queue until the official start of the session designated in the order instruction. Third, proposed Rule 1.5(ll) would define “Equity Data Plans” to mean the effective national market system plan(s) governing the collection, consolidation, processing, and dissemination of consolidated equity market data via the exclusive securities information processors (“SIPs”), including: (1) the Consolidated Tape Association Plan (“CTA Plan”); (2) the Consolidated Quotation Plan (“CQ Plan”); (3) the Joint Self-Regulatory Organization Plan Governing the Collection, Consolidation and Dissemination of Quotation and Transaction Information for Nasdaq-Listed Securities Traded on Exchanges on an Unlisted Trading Privileges Basis (“UTP Plan”); (4) the CT Plan established by the Limited Liability Company Agreement of CT Plan LLC; and (5) any successor to the named Plan(s). Finally, the Exchange proposes a non-substantive amendment to Rule 1.5(ii) to correct a typographical error, changing the word “Continent” to “Contingent.” As amended, Rule 1.5(ii) would define the Regular Session as “the time between the completion of the Opening Process or Contingent Open as defined in Rule 11.7 and 4:00 p.m. Eastern Time.” Trading Rules The Exchange proposes to amend Rules 11.1 (Hours of Trading and Trading Days), 11.6 (Definitions), 11.7 (Opening Process), 11.8 (Order Types), 11.10 (Order Execution), 11.15 (Clearly Erroneous Executions) and to adopt Rule 11.25 (Weekday Trading Pauses) to reflect necessary updates to provide for 23x5 trading functionality. a. Rule 11.1—Hours of Trading and Trading Days The Exchange proposes to amend Rule 11.1(a) to replace reference to the Early Trading Session with the Overnight Trading Session, and to amend Rule 11.1(a)(1) to update the order entry window and session eligibility framework to accommodate 23x5 Trading. Under current Rule 11.1(a)(1), Users may enter orders into the System beginning at 2:30 a.m. Orders entered between 2:30 a.m. and 4:00 a.m. are not eligible for execution until the start of the Early Trading Session, Pre-Opening Session, or Regular Trading Hours, depending on the TIF instruction selected. The current rule also provides for two start times within the Early Trading Session (a 4:00 a.m. Start and a 7:00 a.m. Start) each with distinct order acceptance restrictions. The Exchange proposes to replace this framework with a streamlined structure that reflects the introduction of the Overnight Trading Session and the expanded order entry window. As proposed, Users may enter orders into the System beginning at the Order Acceptance Queueing Time (8:55 p.m.) on each night preceding a business day through 8:00 p.m. on the following calendar day, provided that the following calendar day is a business day. Orders entered during the Order Acceptance Queueing Time will queue until the official start of the session designated in the order instruction. This approach applies uniformly across all trading sessions ( i.e., the Overnight Trading Session, Pre-Opening Session, Regular Session, and Post-Closing Session) providing Members with a consistent and simplified order entry experience. The 4:00 a.m. Start and 7:00 a.m. Start construct is removed, as these designations are no longer necessary under the proposed framework. Proposed Rule 11.1(a)(2) would provide that an order is eligible to participate in the designated trading session(s) only and may remain in effect for one or more consecutive trading sessions on a particular day. An order designated for a session that has not yet begun will be accepted into the System but will not be eligible to trade until that session commences. An order designated solely for a session that has already ended will be rejected. An order entered without a trading session designation will default to a Day  30 order, making it eligible to participate from the Overnight Trading Session through the end of Regular Trading Hours. Proposed Rule 11.1(a)(2) also permits Members to designate a specific Start Time for their orders in thirty-minute increments prior to the start of Regular Trading Hours, replacing the 4:00 a.m. Start and 7:00 a.m. Start designations with a more flexible and uniform framework. Start Times must be set to a time prior to the commencement of Regular Trading Hours and may not be designated during Regular Trading Hours. At each Start Time, orders will be handled in time sequence beginning with the oldest time stamp, and will be placed on the EDGX Book, routed, cancelled, or executed in accordance with the terms of the order. 30  An instruction the User may attach to an order stating that an order to buy or sell which, if not executed, expires at the end of Regular Trading Hours. Any Day Order entered into the System before the opening for business on the Exchange as determined pursuant to Rule 11.1, or after the closing of Regular Trading Hours, will be rejected. See Exchange Rule 11.6(q)(2). Proposed Rule 11.1(a)(3) would specify the orders the Exchange will not accept during the Order Acceptance Queueing Time: (i) orders with a Post Only instruction; (ii) ISOs; (iii) Market Orders, other than those with a TIF instruction of RHO or a Stop Price;  31 (iv) orders with a Minimum Execution Quantity instruction that also include a TIF instruction of RHO; and (v) orders with a TIF instruction of IOC or FOK. These restrictions are consistent with the order type limitations currently applicable prior to the pre-market sessions and are intended to ensure orderly trading prior to the commencement of the Overnight Trading Session. 31  Once the trigger price is reached during Regular Trading Hours, the order will be elected (activated). Election results in a Market order sent to the book. See Cboe Titanium U.S. Equities FIX Specification, at 61, available at https://cdn.cboe.com/resources/membership/Cboe_US_Equities_FIX_Specification.pdf. The Exchange also proposes to amend Rule 11.1(b) to define “business day” and to specify the days on which the Exchange will be open for trading under the proposed 23x5 framework. A business day is any day the Exchange is open for trading, which includes any Monday, Tuesday, Wednesday, Thursday, and Friday, other than a holiday listed below, and shall be deemed to begin at 9:00 p.m. on the preceding calendar day. The Exchange will not be open for business on the following holidays: New Year's Day, Dr. Martin Luther King Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day. When a holiday falls on a Saturday, the Exchange will not be open for business on the preceding Friday. When a holiday falls on a Sunday, the Exchange will not be open for business on the following Monday, unless otherwise indicated by the Exchange. On days when the Exchange closes early (“Early Market Close”), Regular Trading Hours will be from 9:30 a.m. to 1:00 p.m. and the Post-Closing Session will be from 1:00 p.m. to 5:00 p.m. Trading shall resume with the Overnight Trading Session on any night preceding a business day. Under the proposed 23x5 framework, the trading day will be structured as follows. The Overnight Trading Session will run from 9:00 p.m. to 4:00 a.m., followed by the Pre-Opening Session from 4:00 a.m. to 9:30 a.m., Regular Trading Hours from 9:30 a.m. to 4:00 p.m., and the Post-Closing Session from 4:00 p.m. to 8:00 p.m. Between 8:00 p.m. and 9:00 p.m. each weekday, the Exchange will pause trading to conduct maintenance, testing, and processing of corporate actions (such as mergers, stock splits, and dividends) that become effective the following trading day. This pause also provides market participants with time to process and clear trades before the start of a new trading day. For dates on which the Exchange is not open for business under Rule 11.1(b), the market closure will be effective at 8:00 p.m. on the calendar day preceding the closure date. For Early Market Close days, 32 the closure will instead be effective at 5:00 p.m. on the calendar day preceding the closure date. In either case, the Exchange will re-open at 9:00 p.m. on the closure date, unless the closure date is immediately followed by a non-business day, in which case the Exchange will re-open at 9:00 p.m. on the day preceding the next business day. 32  Regular trading hours for days when the markets close early are typically 9:30 a.m. to 1:00 p.m. See e.g., Thanksgiving Early Close and Christmas Early Close at https://www.cboe.com/about/hours. b. Rule 11.6(q)(2)—TIF Day Instructions The Exchange does not propose any changes to its existing TIF instructions in connection with the Overnight Trading Session, with one exception described below. The Exchange believes the existing TIF framework otherwise accommodates the proposed 23x5 structure without modification. The Exchange proposes a conforming amendment to the Day order TIF definition to permit acceptance of Day Orders during the Overnight Trading Session. Under the current definition, a Day Order entered “after the closing of Regular Trading Hours” is rejected. Because the Overnight Trading Session commences at 9:00 p.m. the current definition would, as written, result in the rejection of Day Orders entered during the Overnight Trading Session or during the Order Acceptance Queueing Time preceding it. This outcome is inconsistent with the proposed 23x5 framework, under which Day Orders should be eligible for entry beginning at the Order Acceptance Queueing Time and should remain eligible for execution throughout the Overnight Trading Session, Pre-Opening Session, and Regular Trading Hours. Accordingly, the Exchange proposes to amend the Day order TIF definition to provide that a Day Order entered during the Overnight Trading Session or during the Order Acceptance Queueing Time will be accepted by the Exchange and, if not executed, will expire at the end of Regular Trading Hours on the following business day. This amendment is limited to conforming the Day order definition to the expanded order entry window introduced by the proposed 23x5 framework and does not alter any other aspect of the Day order TIF instruction. For the avoidance of doubt, orders will expire on the business day for which they are entered; as described above, a business day is deemed to begin at 9:00 p.m. Eastern Time on the preceding calendar day. As amended, a Day Order entered at 9:00 p.m. on a day preceding a business day will remain eligible for execution throughout the Overnight Trading Session, Pre-Opening Session, and Regular Trading Hours on that business day, expiring at 4:00 p.m. Eastern Time that day. c. Rule 11.7—Opening Process The Exchange proposes a conforming amendment to Rule 11.7 to replace the reference to the Early Trading Session with the Overnight Trading Session in the provision governing re-openings after a halt. As amended, during the Overnight Trading Session, Pre-Opening Session, or Post-Closing Session, the Re-Opening Process will occur at the midpoint of the NBBO after one second has passed following the applicable resumption trigger. This change is non-substantive and is intended solely to reflect the replacement of the Early Trading Session with the Overnight Trading Session under the proposed 23x5 framework. d. Rule 11.8—Order Types The Exchange proposes conforming amendments to Rule 11.8 to replace references to the Early Trading Session with the Overnight Trading Session across each order type that currently specifies session eligibility, including Limit Orders, ISOs, MidPoint Peg Orders, 33 Market Maker Peg Orders, 34 Supplemental Peg Orders, 35 and MidPoint Discretionary Orders. 36 33   See Exchange Rule 11.8(d). 34   See Exchange Rule 11.8(e). 35   See Exchange Rule 11.8(f). 36   See Exchange Rule 11.8(g). A Market Order is only eligible for execution by the System during the Regular Session. See Exchange Rule 11.8(a)(5). Outside of Regular Trading Hours, only Limit Orders are eligible for execution. Under proposed Rule 11.8(a)(6), a Limit Order may be eligible for execution during the Overnight Trading Session, Pre-Opening Session, Regular Session, Regular Trading Hours, and the Post-Closing Session. This is consistent with the other order types eligible outside of Regular Trading Hours; ISOs must be Limit Orders by definition, and Market Maker Peg Orders, Supplemental Peg Orders, and MidPoint Discretionary Orders are each expressly defined as or characterized as Limit Orders under their respective provisions. Limit MidPoint Peg Orders, which are capped with respect to price, may be executed during the Overnight Trading Session, Pre-Opening Session, Regular Trading Hours, and the Post-Closing Session, while Market MidPoint Peg Orders, which are uncapped with respect to price, may only be executed during Regular Trading Hours. Because a Market MidPoint Peg Order carries no price cap, it presents heightened execution risk in extended hours sessions where liquidity conditions may differ materially from those present during Regular Trading Hours and where the NBBO may be wider or less reliable. Without a limit price to constrain execution, a Market MidPoint Peg Order could execute at a price that is disadvantageous to the submitting party in a manner that is less likely to occur during Regular Trading Hours. By contrast, Limit MidPoint Peg Orders have a price cap and are non-displayed, which the Exchange views as sufficient safeguards to make them suitable for execution outside of Regular Trading Hours, consistent with the broader principle that only Limit Orders are eligible for execution outside of Regular Trading Hours under the proposed 23x5 framework. Proposed Rule 11.8(d)(4) also provides that a Minimum Execution Quantity instruction on a MidPoint Peg Order will not be applied during the Opening Process. Additionally, proposed Rule 11.8(d)(4) replaces the reference to the Early Trading Session with the Overnight Trading Session, conforming MidPoint Peg Order session eligibility to the proposed 23x5 framework. The Exchange also proposes to amend Rule 11.8(e)(7) to replace the reference to the Early Trading Session with the Overnight Trading Session for Market Maker Peg Orders. As amended, Users may submit Market Maker Peg Orders to the Exchange starting at the beginning of the Overnight Trading Session, though such orders will not be executable or automatically priced until after the commencement of Regular Session. All remaining amendments to Rule 11.8 (including those applicable to ISOs, Supplemental Peg Orders, and MidPoint Discretionary Orders) are non-substantive and are intended solely to conform existing session eligibility provisions to the proposed 23x5 framework by replacing references to the Early Trading Session with the Overnight Trading Session. e. Rule 11.10—Order Execution The Exchange proposes a conforming amendment to Rule 11.10 to replace the reference to the Early Trading Session with the Overnight Trading Session in the provision governing compliance with Regulation NMS. As amended, for any execution to occur during the Overnight Trading Session, Pre-Opening Session, or Post-Closing Session, the price must be equal to or better than the highest bid or lowest offer in the EDGX Book or as disseminated by the responsible single plan processor, unless the order is marked ISO or a Protected Bid is crossing a Protected Offer. This amendment is non-substantive and preserves the existing execution standard applicable outside of Regular Trading Hours. f. Rule 11.15—Clearly Erroneous Executions The Exchange proposes conforming amendments to Rule 11.15 to replace all references to the Early Trading Session with the Overnight Trading Session throughout the clearly erroneous execution framework. These amendments appear in the provisions governing review of transactions occurring outside of Regular Trading Hours, including the numerical guidelines table, the Multi-Stock Event provisions, the additional factors provision, the Outlier Transaction provision, the Reference Price provision, and the Officer Acting On Own Motion provision. In each case, the amendment substitutes “Overnight Trading Session” for “Early Trading Session” without altering the substantive standards or procedures applicable to clearly erroneous execution reviews. The Exchange notes that the numerical guidelines applicable to the Overnight Trading Session, Pre-Opening Session, and Post-Closing Session will remain the same as those currently applicable to the Early Trading Session, Pre-Opening Session, and Post-Closing Session, reflecting the Exchange's view that the same heightened thresholds appropriate for extended hours trading remain appropriate for the Overnight Trading Session. g. Rule 11.25—Weekday Trading Pause The Exchange proposes to adopt new Rule 11.25 to govern the daily trading pause that will occur between the close of the Post-Closing Session and the commencement of the Overnight Trading Session on each weekday. As proposed, the Exchange will pause trading at the conclusion of the Post-Closing Session at 8:00 p.m. and resume trading with the commencement of the Overnight Trading Session at 9:00 p.m. on the day preceding the next business day. This one-hour pause is intended to provide the Exchange with time to conduct necessary maintenance and testing, and to process corporate actions, such as mergers, stock splits, and dividends, that become effective the following trading day. The pause also provides market participants with time to process and clear trades before the start of a new trading day. Proposed Rule 11.25(a)(1) provides that all orders outstanding on the EDGX Book as of 8:00 p.m. at the end of the Post-Closing Session will be cancelled. The Exchange believes it is appropriate to cancel all resting orders at the close of the Post-Closing Session each weekday to ensure that orders are not carried over into the next trading day without an explicit order instruction by a Member. This approach provides Members with a clean start to each trading day and reduces the risk of unintended executions based on stale order instructions. Proposed Rule 11.25(a)(2) provides that the Exchange will begin accepting orders again at the Order Acceptance Queueing Time ( i.e., 8:55 p.m.) and will continue accepting orders through 8:00 p.m. on the following calendar day, provided the next calendar day is a business day. Orders entered during the Order Acceptance Queueing Time will queue until the commencement of the Overnight Trading Session at 9:00 p.m. Proposed Rule 11.25(a)(2) also provides that trades occurring at or after the commencement of the Overnight Trading Session at 9:00 p.m. will be assigned a trade date of the following calendar day, reflecting that the Overnight Trading Session economically belongs to the next trading day even though it commences the prior evening. The Exchange notes that while the Order Acceptance Queueing Time applies on Sunday prior to the commencement of the Overnight Trading Session at 9:00 p.m., the one-hour trading pause described in Rule 11.25(a) does not apply on Sunday. Unlike Monday through Thursday, where trading pauses at 8:00 p.m. following the close of the Post-Closing Session and resumes at 9:00 p.m., Sunday does not follow a Post-Closing Session and therefore there is no intervening pause period. The Exchange will begin accepting orders at the Order Acceptance Queueing Time on Sunday evening and the Overnight Trading Session will commence at 9:00 p.m., marking the start of the trading week. The Exchange believes this distinction is appropriate because the operational and processing considerations that necessitate a pause between the Post-Closing Session and the Overnight Trading Session on weekdays, such as processing corporate actions and clearing end-of-day positions, are not present on Sunday. Unlisted Trading Privileges The Exchange proposes conforming amendments to Rule 14.1 to replace references to the Early Trading Session with the Overnight Trading Session. Specifically, the Exchange proposes to amend Rule 14.1(c)(1) to replace the reference to the “Early Trading Session (7:00 a.m.-8:00 a.m. Eastern Time)” with the “Overnight Trading Session (9:00 p.m.-4:00 a.m. Eastern Time).” The Exchange also proposes conforming amendments to Interpretations and Policies .01(a) and .01(b)(2) to replace each reference to the “Early Trading Session” with the “Overnight Trading Session.” These amendments are non-substantive and are intended solely to conform the unlisted trading privileges framework to the proposed 23x5 session structure by updating the applicable session nomenclature and hours. Risk Disclosures The Exchange proposes to adopt new Rule 3.21(h) to establish tailored customer disclosure obligations specific to the Overnight Trading Session and Pre-Opening Session. The existing customer disclosure framework under Rule 3.21 requires Members to disclose the material trading risks associated with extended hours trading prior to accepting an order for execution in those sessions. The Exchange believes that the unique characteristics of the Overnight Trading Session and Pre-Opening Session (including the hours during which they operate, the market conditions that may be present, and the novel nature of overnight exchange trading) warrant additional disclosures beyond those currently required for other extended hours sessions. Proposed Rule 3.21(h) sets forth seven categories of risks that Members must disclose to customers in connection with trading during the Overnight Trading Session and Pre-Opening Session. First, proposed Rule 3.21(h)(1) addresses the risk of trading during hours in which primary listing markets may not be open. Unlike the Post-Closing Session, which occurs in close proximity to Regular Trading Hours, the Overnight Trading Session and Pre-Opening Session operate during hours in which primary listing exchanges may not be conducting their own trading, regulatory surveillance, or other regulatory functions with respect to their listed securities. The Exchange believes it is important that customers understand that the regulatory infrastructure ordinarily provided by primary listing exchanges may not be available during these sessions. Second, proposed Rule 3.21(h)(2) addresses the risk that regulatory protections available during the Overnight Trading Session and Pre-Opening Session may be more limited or different than those available during Regular Trading Hours. For example, certain volatility control mechanisms applicable to individual symbols and the broader equities market may not be available during the Overnight Trading Session and Pre-Opening Session. The Exchange believes customers should be informed of these potential gaps in regulatory protections before trading during these sessions. Third, proposed Rule 3.21(h)(3) addresses the risk arising from limited trading alternatives during the Overnight Trading Session and Pre-Opening Session. Because the Exchange may be the only exchange trading certain securities during these hours, customers may face greater exposure to losses in the event of systems failures or other operational issues on the Exchange, as alternative execution venues may not be available. Fourth, proposed Rule 3.21(h)(4) addresses the risks associated with near-continuous trading under the 23x5 framework. With the implementation of the Overnight Trading Session, trading on the Exchange will occur on a near-continuous basis throughout the week, with only limited breaks. This structure may present heightened risks related to system maintenance and testing, as well as the pausing and resumption of trading, as there will be fewer extended breaks during which such activities can be conducted without impacting market participants. Fifth, proposed Rule 3.21(h)(5) addresses the risk of trading during hours in which financial market infrastructure companies are closed. Certain important financial market infrastructure providers, including other markets, banks, Fedwire Funds Service, and certain other providers of settlement services, may be closed during the Overnight Trading Session and Pre-Opening Session. Trading during hours in which the relevant clearing agency and other settlement service providers are closed may result in an increased passage of time between the execution of a transaction and its final settlement, which may expose customers to additional counterparty and settlement risk. Sixth, proposed Rule 3.21(h)(6) addresses the risk arising from the novel nature of overnight exchange trading. Exchange-facilitated trading during overnight hours is a relatively new development in the U.S. equities market, and as such, the Overnight Trading Session may present unforeseen risks that are not yet fully understood or anticipated. The Exchange believes it is appropriate to specifically call out the novelty of the Overnight Trading Session so that customers can make informed decisions about whether overnight trading is appropriate for them. Seventh, proposed Rule 3.21(h)(7) provides a general catch-all disclosure acknowledging that the Overnight Trading Session and Pre-Opening Session may present additional unforeseen risks beyond those specifically enumerated in proposed Rule 3.21(h)(1) through (6). The Exchange believes this provision is appropriate given the evolving nature of extended hours trading and the potential for market conditions or operational circumstances that cannot be fully anticipated at this time. The Exchange believes that the proposed disclosures under Rule 3.21(h) are necessary and appropriate to ensure that customers are fully informed of the unique risks presented by the Overnight Trading Session and Pre-Opening Session prior to participating in trading during those hours. The proposed disclosures are consistent with the customer protection principles underlying the existing Rule 3.21 framework and reflect the Exchange's commitment to investor protection in connection with the expansion of its trading hours under the proposed 23x5 framework. Protections The implementation of 23x5 Trading represents an extension of trading hours rather than a fundamental restructuring of Exchange operations or rules. With the exception of the specific amendments discussed above, the Exchange's operational processes, rule text, and surveillance programs will continue to apply in the same manner as they do today. The following EDGX rules and system features will remain unchanged and will apply in full during the Overnight Trading Session: Order Types and Order Execution; Membership Rules and Rules of Fair Practice; Market Maker Obligations and Priority of Orders; Trading Practice Rules and Disciplinary Rules and Enforcement; Opening and Closing Crosses; Clearly Erroneous Execution Protections; and Risk Settings and Fat Finger Protections. With respect to trading halts, the Exchange's existing halt rules will apply during the Overnight Trading Session. Consistent with current practice during other extended hours sessions, the Exchange will halt trading in a security during the Overnight Trading Session to the extent required to follow a halt imposed by the primary listing exchange for that security. To the extent a security is subject to a regulatory halt, news dissemination halt, or other trading pause imposed by the primary listing exchange or a national securities regulator, the Exchange will halt trading in that security consistent with applicable rules and regulatory requirements. The Exchange's clearly erroneous execution rules under Rule 11.15 will apply in full during the Overnight Trading Session, as they currently apply during the Early Trading Session and other extended hours sessions. No substantive changes to those rules are proposed in connection with this filing. As such, the Exchange's Clearly Erroneous rules will continue to mirror those adopted by each national security exchange and will continue to ensure that there are consistent standards across each exchange for breaking trades, and continuing to promote the orderly and efficient operation of the equities markets. The Exchange's existing surveillance programs and compliance infrastructure will likewise apply fully to trading in the Overnight Trading Session and the modified Pre-Opening Session. The Exchange currently operates a comprehensive regulatory program applicable to the Early Trading Session, Pre-Opening Session, Regular Trading Hours, and Post-Closing Session, encompassing a suite of automated trade surveillance tools, routine Member examinations, and an exam-based regulatory program. This regulatory program will extend to the Overnight Trading Session without modification, ensuring that Members trading during overnight hours are subject to the same level of oversight applicable to trading in other sessions. Similarly, the Exchange's existing risk settings and controls (including single-order price and size protections and other fat finger safeguards) will remain available and operative during the Overnight Trading Session. The Exchange believes that these existing protections, taken together, provide a robust framework for managing risk during overnight trading that is consistent with the protections available during other extended hours sessions. Contingency on Industry Readiness As noted above, the Exchange will not implement its proposed rule changes or commence operation of the Overnight Trading Session until the Equity Data Plan readiness conditions set forth in proposed Rule 1.5(jj) have been satisfied. Prior to commencing operation of the Overnight Trading Session, the Exchange will file a proposed rule change pursuant to Section 19(b) of the Exchange Act and the rules thereunder confirming that: (i) the Exchange is able to comply with its obligations under the Exchange Act and the rules thereunder during the Overnight Trading Session; and (ii) the Equity Data Plans are prepared to collect, consolidate, process, and disseminate quotation and transaction information at all times during the Overnight Trading Session. Upon satisfaction of the foregoing conditions, the Exchange will announce via Exchange notice the implementation date for its proposed rule changes and the go-live date for 23x5 Trading. If the Overnight Trading Session Proposed Rule Change is not filed within 18 months of the SEC's approval of this proposed rule change, the Exchange will promptly file a proposed rule change to remove the rules applicable to the Overnight Trading Session. Impact on Fees Any impact of the Exchange's 23x5 proposal on its fee schedule will be addressed in a subsequent fee filing. 2. Statutory Basis The Exchange believes the proposed rule change is consistent with the Securities Exchange Act of 1934 (the “Act”) and the rules and regulations thereunder applicable to the Exchange and, in particular, the requirements of Section 6(b) of the Act. 37 Specifically, the Exchange believes the proposed rule change is consistent with the Section 6(b)(5)  38 requirements that the rules of an exchange be designed to prevent fraudulent and manipulative acts and practices, to promote just and equitable principles of trade, to foster cooperation and coordination with persons engaged in regulating, clearing, settling, processing information with respect to, and facilitating transactions in securities, to remove impediments to and perfect the mechanism of a free and open market and a national market system, and, in general, to protect investors and the public interest. 37  15 U.S.C. 78f(b). 38  15 U.S.C. 78f(b)(5). 23x5 Trading Framework The Exchange believes the proposed rule change is consistent with the Act because it would remove impediments to and perfect the mechanism of a free and open market and a national market system by providing a rules framework to support 23x5 Trading. As described above, the Exchange has observed sustained and significant growth in Early Trading Session volume, with average daily volume across Cboe's U.S. equities exchanges increasing 404% between January 2022 and February 2026. The Exchange has also received consistent feedback from APAC broker-dealers that their retail investors desire greater access to the U.S. equities market during their local business hours. The Exchange believes that 23x5 Trading will benefit investors and the national market system by increasing market accessibility, promoting capital formation, and facilitating portfolio management, including for the growing number of retail investors in the Asia-Pacific region whose local business hours do not coincide with U.S. Regular Trading Hours. The Exchange further believes the proposal is consistent with the Act because the proposed Overnight Trading Session and the modified Pre-Opening Session will operate in substantially the same manner as the Exchange's existing extended hours sessions. All order types, execution processes, membership rules, market maker obligations, priority rules, disciplinary rules, clearly erroneous execution protections, risk settings, and fat finger safeguards applicable to the Exchange's existing sessions will continue to apply in full during the Overnight Trading Session and the expanded Pre-Opening Session. The Exchange believes that applying its existing operational and regulatory framework to the Overnight Trading Session is consistent with the Act's goals of ensuring market integrity, investor protection, and fair and orderly trading. The Exchange represents that its systems have the capacity to accommodate the proposed 23x5 Trading functionality. Session Definitions and Order Entry Framework The Exchange believes that the proposed new definitions, including the Overnight Trading Session, Order