Self-Regulatory Organizations; MEMX LLC; Notice of Filing and Immediate Effectiveness of a Proposal To Amend Exchange Rule 11.6(q)(1), Round Lot, To Conform With the Amendment to the Definition of Round Lot Under Rule 600 of Regulation NMS Recently Approved by the Commission

<NOTICE> SECURITIES AND EXCHANGE COMMISSION <DEPDOC>[Release No. 34-104300; File No. SR-MEMX-2025-33]</DEPDOC> <SUBJECT>Self-Regulatory Organizations; MEMX LLC; Notice of Filing and Immediate Effectiveness of a Proposal To Amend Exchange Rule 11.6(q)(1), Round Lot, To Conform With the Amendment to the Definition of Round Lot Under Rule 600 of Regulation NMS Recently Approved by the Commission</SUBJECT> <DATE>December 3, 2025.</DATE> Pursuant to Section 19(b)(1) of the Securities Exchange Act of 1934 (the “Act”), <SU>1</SU> <FTREF/> and Rule 19b-4 thereunder, <SU>2</SU> <FTREF/> notice is hereby given that on November 25, 2025, MEMX LLC (“MEMX” or the “Exchange”) filed with the Securities and Exchange Commission (the “Commission”) the proposed rule change as described in Items I and II below, which Items have been prepared by the Exchange. The Exchange filed the proposal as a “non-controversial” proposed rule change pursuant to Section 19(b)(3)(A)(iii) of the Act  <SU>3</SU> <FTREF/> and Rule 19b-4(f)(6) thereunder. <SU>4</SU> <FTREF/> The Commission is publishing this notice to solicit comments on the proposed rule change from interested persons. <FTNT> <SU>1</SU>  15 U.S.C. 78s(b)(1). </FTNT> <FTNT> <SU>2</SU>  17 CFR 240.19b-4. </FTNT> <FTNT> <SU>3</SU>  15 U.S.C. 78s(b)(3)(A). </FTNT> <FTNT> <SU>4</SU>  17 CFR 240.19b-4. </FTNT> <HD SOURCE="HD1">I. Self-Regulatory Organization's Statement of the Terms of Substance of the Proposed Rule Change</HD> The Exchange is filing with the Commission a proposed rule change to amend Rule 11.6(q)(1), Round Lot, to conform with a recent amendment to the definition of round lot under Rule 600 of Regulation NMS recently approved by the Commission. <SU>5</SU> <FTREF/> The Exchange also proposes to make conforming, non-substantive changes to Exchange Rules 11.9(b)(2)(A)-(D) and Exchange Rule 11.20(d)(1). The text of the proposed rule change is provided in Exhibit 5 and is available on the Exchange's website at <E T="03">https://info.memxtrading.com/regulation/rules-and-filings/.</E> <FTNT> <SU>5</SU>   <E T="03">See</E> Securities Exchange Act Release No. 101070 (September 18, 2024), 89 FR 81620 (October 8, 2024) (S7-30-22). </FTNT> <HD SOURCE="HD1">II. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Change</HD> 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. <HD SOURCE="HD2">A. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Change</HD> <HD SOURCE="HD3">1. Purpose</HD> The Exchange proposes to amend Rule 11.6(q)(1), Round Lot, to conform with the definition of round lot under Rule 600 of the Regulation NMS that is to be implemented in November 2025. <SU>6</SU> <FTREF/> The Exchange also proposes to make conforming non-substantive changes to Rules 11.9(b)(2)(A)-(D), Priority of Orders, Dissemination, and Rule 11.20(d)(1), Continuous, Two-Sided Quote Obligation. <FTNT> <SU>6</SU>   <E T="03">See supra</E> note 5. </FTNT> In 2020, the Commission adopted amendments to Regulation NMS to modernize the NMS information provided within the national market system for the benefit of market participants and to better achieve Section 11A's goals of assuring “the availability to brokers, dealers, and investors of information with respect to quotations for and transactions in securities that is prompt, accurate, reliable, and fair” (“MDI Rules”). <SU>7</SU> <FTREF/> These changes included an amendment to Rule 600 of Regulation NMS to include a definition of “round lot” that assigns each NMS stock to a round lot size based on the stock's average closing price. <SU>8</SU> <FTREF/> Prior to this change, a “round lot” was not defined in the Act or Regulation NMS. The definition of a “round lot” was included in the rules of the individual exchanges, including Exchange Rule 11.6(q)(1), which defined a “Round Lot” as 100 shares or any multiple thereof, but the rules also generally allowed the exchanges, or the primary listing exchange for the security, discretion to define “round lot” otherwise. <FTNT> <SU>7</SU>   <E T="03">See</E> Securities Exchange Act Release No. 90610 (December 9, 2020), 86 FR 18596 (April 9, 2021) (“MDI Adopting Release”). </FTNT> <FTNT> <SU>8</SU>   <E T="03">See id.</E> </FTNT> On September 18, 2024, the Commission accelerated the implementation of the round lot definition. <SU>9</SU> <FTREF/> The Commission also revised the round lot definition as set forth below. <SU>10</SU> <FTREF/> Rule 600(b)(93) of Regulation NMS, as adopted by the MDI Rules and as amended in 2024, <SU>11</SU> <FTREF/> defines a round lot for NMS stocks  <SU>12</SU> <FTREF/> that have an average closing price on the primary listing exchange during the prior Evaluation Period  <SU>13</SU> <FTREF/> of: (1) $250.00 or less per share as 100 shares; (2) $250.01 to $1,000.00 per share as 40 shares; (3) $1,000.01 to $10,000.00 per share as 10 shares; and (4) $10,000.01 or more per share as 1 share. <SU>14</SU> <FTREF/> For any security that becomes an NMS Stock during an operative period, as described in Rule 600(b)(93)(iv), <SU>15</SU> <FTREF/> a round lot is 100 shares. Adjustments to the round lot size for a security will occur on a semiannual basis and the calculation of the average closing price on the primary listing exchange will be based on a one month “Evaluation Period.”  <SU>16</SU> <FTREF/> The revised definition of round lot is to be implemented on November 3, 2025, the first business day of November 2025. <SU>17</SU> <FTREF/> <FTNT> <SU>9</SU>   <E T="03">See supra</E> note 5. </FTNT> <FTNT> <SU>10</SU>   <E T="03">See supra</E> note 5. </FTNT> <FTNT> <SU>11</SU>   <E T="03">See supra</E> note 5. </FTNT> <FTNT> <SU>12</SU>  “NMS stock” is defined under Regulation NMS as any NMS security other than an option. 17 CFR 242.600(b)(65). </FTNT> <FTNT> <SU>13</SU>  Rule 600(b)(93)(iii) of Regulation NMS defines the Evaluation Period as “(A) all trading days in March for the round lot assigned on the first business day in May and (B) all trading days in September for the round lot assigned on the first business day of November during which the average closing price of an NMS stock on the primary listing exchange shall be measured by the primary listing exchange to determine the round lot for each NMS stock.” </FTNT> <FTNT> <SU>14</SU>   <E T="03">See supra</E> note 5. </FTNT> <FTNT> <SU>15</SU>  Pursuant to Rule 600(b)(93)(iv) of Regulation NMS the round lot assigned under the section “shall be operative on (A) the first business day of May for the March Evaluation Period and continue through the last business day of October of the calendar year, and (B) the first business day of November for the September Evaluation Period and continue through the last business day of April of the next calendar year.” </FTNT> <FTNT> <SU>16</SU>   <E T="03">See supra</E> note 5. </FTNT> <FTNT> <SU>17</SU>   <E T="03">See supra</E> note 5. </FTNT> The Exchange now proposes to amend Exchange Rule 11.6(q)(1), Round Lot, to conform with the definition of round lot under Rule 600 of the Regulation NMS. Exchange Rule 11.6(q)(1) provides that “[O]ne hundred (100) shares or any multiple thereof shall constitute a Round Lot, unless an alternative number of shares is established as a Round Lot by the listing exchange for the security.” The Exchange now proposes to replace this sentence with a sentence that explicitly refers to the definition of round lot under Rule 600 of Regulation NMS. As a result, the above sentence will be deleted and replaced with the following, “[a] Round Lot for each NMS Stock shall be the size assigned by the primary listing market pursuant to Rule 600 of Regulation NMS under the Exchange Act.” Again, this change is being proposed solely to conform the Exchange's definition of “Round Lot” under Exchange Rule 11.6(q)(1) to the new definition of Round Lot under Rule 600 of Regulation NMS. The Exchange also proposes to make conforming non-substantive changes to Exchange Rules 11.9(b)(2)(A)-(D), Priority of Orders, Dissemination, and Exchange Rule 11.20(d)(1), Continuous, Two-Sided Quote Obligation. The Exchange proposes to capitalize the term “round lot” in Rule 11.9(b)(2)(A)-(D). In addition, the Exchange proposes to amend Exchange Rule 11.20(d)(1) to conform with the Exchange's definition of Round Lot. Exchange Rule 11.20(d)(1) currently provides that “[u]nless otherwise designated, a `normal unit of trading' shall be 100 shares.” The Exchange proposes to replace the aforementioned sentence with a sentence that conforms to the newly adopted definition of Round Lot in the Exchange's Rulebook. As a result, the above sentence will be deleted and replaced with the following: “[u]nless otherwise designated, a `normal unit of trading' shall be a Round Lot as defined in Exchange Rule 11.6(q)(1).” The purpose of these changes is to provide greater clarity to Exchange Members  <SU>18</SU> <FTREF/> and the public regarding the Exchange's Rulebook. The Exchange does not propose any additional rule changes. The proposed rule changes will be implemented immediately. <FTNT> <SU>18</SU>   <E T="03">See</E> Exchange Rule 1.5(p). A “Member” is defined as “any registered broker or dealer that has been admitted to membership in the Exchange.” </FTNT> <HD SOURCE="HD3">2. Statutory ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 20k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━