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 May 29, 2026, MEMX LLC (“MEMX” or the “Exchange”) 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.

I. Self-Regulatory Organization's Statement of the Terms of Substance of the Proposed Rule Change

The Exchange is filing with the Commission a proposed rule change to amend the Exchange's fee schedule applicable to Members ^[3] (the “Fee Schedule”) pursuant to Exchange Rules 15.1(a) and (c). As is further described below, the Exchange proposes to: (i) reduce the base rebate for executions of orders subject to the Exchange's Display-Price Sliding ^[4] that add liquidity to the Exchange and receive price improvement when executed (such orders, “Added Price Improved Volume”); (ii) reduce the base rebate for executions of orders that add non-displayed liquidity to the Exchange (such orders, “Added Non-Midpoint Non-Displayed Volume”); (iii) reduce the base rebate provided for executions of Midpoint Peg orders that add non-displayed liquidity to the Exchange (such orders, “Added Midpoint Non-Displayed Volume”); (iv) modify the Non-Display Add Tiers by adopting a new Non-Display Add Tier 2 and eliminating Added Price Improved Volume from the set of execution categories eligible to receive an enhanced rebate under the Non-Display Add Tiers; (v) eliminate the Display-Price Sliding Tier 1; (vi) reduce the additive rebate provided under the Tape A Quoting Tier; and (vii) reduce the ( printed page 36027) additive rebate provided under the Tape C Quoting Tier. The Exchange proposes to implement the changes to the Fee Schedule pursuant to this proposal on June 1, 2026. The text of the proposed rule change is provided in Exhibit 5.

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 purpose of the proposed rule change is to amend the Fee Schedule to: (i) reduce the base rebate for executions of orders subject to the Exchange's Display-Price Sliding ^[5] that add liquidity to the Exchange and receive price improvement when executed (such orders, “Added Price Improved Volume”); (ii) reduce the base rebate for executions of orders that add non-displayed liquidity to the Exchange (such orders, “Added Non-Midpoint Non-Displayed Volume”); (iii) reduce the base rebate provided for executions of Midpoint Peg orders that add non-displayed liquidity to the Exchange (such orders, “Added Midpoint Non-Displayed Volume”); (iv) modify the Non-Display Add Tiers by adopting a new Non-Display Add Tier 2 and eliminating Added Price Improved Volume from the set of execution categories eligible to receive an enhanced rebate under the Non-Display Add Tiers; (v) eliminate the Display-Price Sliding Tier 1; (vi) reduce the additive rebate provided under the Tape A Quoting Tier; and (vii) reduce the additive rebate provided under the Tape C Quoting Tier, each as further described below.

The Exchange first notes that it operates in a highly competitive market in which market participants can readily direct order flow to competing venues if they deem fee levels at a particular venue to be excessive or incentives to be insufficient. More specifically, the Exchange is only one of 18 registered equities exchanges, as well as a number of alternative trading systems and other off-exchange venues, to which market participants may direct their order flow. Based on publicly available information, no single registered equities exchange currently has more than approximately 14% of the total market share of executed volume of equities trading.^[6] Thus, in such a low-concentrated and highly competitive market, no single equities exchange possesses significant pricing power in the execution of order flow, and the Exchange currently represents approximately 2% of the overall market share.^[7] The Exchange in particular operates a “Maker-Taker” model whereby it provides rebates to Members that add liquidity to the Exchange and charges fees to Members that remove liquidity from the Exchange. The Fee Schedule sets forth the standard rebates and fees applied per share for orders that add and remove liquidity, respectively. Additionally, in response to the competitive environment, the Exchange also offers tiered pricing, which provides Members with opportunities to qualify for higher rebates or lower fees where certain volume criteria and thresholds are met. Tiered pricing provides an incremental incentive for Members to strive for higher tier levels, which provides increasingly higher benefits or discounts for satisfying increasingly more stringent criteria.

Reduce Base Rebate for Added Price Improved Volume

The Exchange currently provides a base rebate of $0.0025 per share for executions of Added Price Improved Volume ^[8] in securities priced above at or above $1.00 per share. The Exchange now proposes to reduce the base rebate for executions of Added Price Improved Volume to $0.0010 per share. The purpose of reducing the base rebate for executions of Added Price Improved [sic] is for business and competitive reasons, as the Exchange believes that reducing such rebate as proposed would decrease the Exchange's expenditures with respect to its transaction pricing in a manner that is still consistent with the Exchange's overall pricing philosophy of encouraging added liquidity to the Exchange. The Exchange is not proposing to change the base rebate for executions of Added Price Improved Volume in securities priced below $1.00 per share.

Reduce Base Rebate for Added Non-Midpoint Non-Displayed Volume

The Exchange currently provides a base rebate of $0.0025 per share for executions of Added Non-Midpoint Non-Displayed Volume in securities priced at or above $1.00 per share.^[9] The Exchange now proposes to reduce the base rebate for executions of Added Non-Midpoint Non-Displayed Volume to $0.0020 per share. The purpose of reducing the base rebate for executions of Added Non-Midpoint Non-Displayed Volume is for business and competitive reasons, as the Exchange believes that reducing such rebate as proposed would decrease the Exchange's expenditures with respect to its transaction pricing in a manner that is still consistent with the Exchange's overall pricing philosophy of encouraging added liquidity to the Exchange. The Exchange is not proposing to change the base rebate for executions of Added Non-Midpoint Non-Displayed Volume in securities priced below $1.00 per share.

Reduce Base Rebate for Added Midpoint Non-Displayed Volume

Similarly, the Exchange currently provides a base rebate of $0.0025 per share for executions of Added Midpoint Non-Displayed Volume in securities priced at or above $1.00 per share.^[10] The Exchange now proposes to reduce the base rebate for executions of Added Midpoint Non-Displayed Volume to $0.0020 per share. The purpose of reducing the base rebate for executions of Added Midpoint Non-Displayed Volume is for business and competitive reasons, as the Exchange believes that reducing such rebate as proposed would decrease the Exchange's expenditures with respect to its transaction pricing in a manner that is still consistent with the Exchange's overall pricing philosophy of encouraging added liquidity to the Exchange. The Exchange is not ( printed page 36028) proposing to change the base rebate for executions of Added Midpoint Non-Displayed Volume in securities priced below $1.00 per share.

Non-Display Add Tiers

The Exchange currently offers Non-Display Add Tier 1 under which a Member may receive an enhanced rebate for executions of Added Non-Displayed Volume by achieving the corresponding required volume criteria for each such tier. Currently, the Added Non-Displayed Volume eligible to qualify for this rebate is comprised of the three following types of orders: (i) Added Midpoint Volume, which as noted above, is assigned the Fee Code “M”; (ii) orders which are not orders subject to Display-Price Sliding that receive price improvement when executed or Midpoint Peg Orders, that add non-displayed liquidity to the Exchange ( i.e. Added Non-Midpoint Non-Displayed Volume), which are assigned the Fee Code “H”; and (iii) Added Price-Improved Volume, which is assigned the Fee Code “P”. At this time, the Exchange is proposing to modify the Non-Display Add Tiers ( i.e. the current Non-Display Add Tier 1 and the newly proposed Non-Display Add Tier 2, as described further below), by removing Added Price Improved Volume from the group of order types eligible to receive the enhanced rebate under any Non-Display Add Tier. Accordingly, only executions of Added Midpoint Non-Displayed Volume and Added Non-Midpoint Non-Displayed Volume will be able to receive the applicable enhanced rebate.^[11] The Exchange, notes, however, that executions of Added Price Improved Volume will continue to be counted towards a Member's Non-Displayed ADAV ^[12] for purposes of meeting the applicable criteria under the Non-Display Add Tiers.

Additionally, the Exchange is proposing to add a new tier under the Non-Display Add Tiers, Non-Display Add Tier 2. Under this tier, the Exchange would provide an enhanced rebate of $0.0025 per share for executions of Added Midpoint Non-Displayed Volume and Added Non-Midpoint Non-Displayed Volume for Members that qualify for such tier by achieving a Non-Displayed ADAV that is equal to or greater than 1,000,000 shares.^[13] The proposed new Non-Display Add Tier 2 is designed to encourage Members to maintain or increase their order flow that adds liquidity, including in the form of non-displayed orders, to the Exchange in order to qualify for the proposed enhanced rebate for executions of Added Non-Displayed Volume, which, in turn, would encourage the submission of additional orders, thereby promoting price discovery and contributing to a deeper and more robust and well-balanced market ecosystem on the Exchange to the benefit of all Members and market participants.

Eliminate Display-Price Sliding Tier 1

Currently, as noted above, the Exchange provides a base rebate of $0.0025 per share for executions of Added Price Improved Volume, which the Exchange is proposing to reduce to $0.0010 per share in connection with this filing. Additionally, the Exchange offers the Display-Price Sliding Tier 1, under which the Exchange provides an enhanced rebate for executions of Added Price Improved Volume if a Member achieves an ADAV ^[14] with respect to Added Price Improved Volume (excluding Retail Orders)^[15] that is equal to or greater than 5,000,000 shares. The “enhanced rebate” is not a set amount, but rather, the highest Added Displayed Volume ^[16] rebate for all of its Added Price Improved Volume transactions during that month, plus any otherwise achieved additive rebates. The Exchange is now proposing to eliminate this Display-Price Sliding Tier 1, as the Exchange no longer wishes to, nor is required to, maintain such tier.

Tape A Quoting Tier

The Exchange currently offers the Tape A Quoting Tier under which a Member may receive an additive rebate of $0.0002 per share for a qualifying Member's executions of Added Displayed Volume (other than Retail Orders) in Tape A securities priced over $1.00 per share by achieving an NBBO Time ^[17] of at least 25% in an average of at least 500 Tape A securities per trading day during the month. Now, the Exchange proposes to reduce the additive rebate provided under the Tape A Quoting Tier to $0.0001 per share.^[18] The Exchange is not proposing to change the criteria required to qualify for Tape A Quoting Tier.

The Exchange believes that the proposed reduction of the additive rebate under the Tape A Quoting Tier ( i.e., by $0.0001 per share) represents a modest reduction and that the proposed additive rebate under Tape A Quoting Tier remains commensurate with the required criteria under such tier and is reasonably related to the market quality benefits that the tier is designed to achieve.

Tape C Quoting Tier

Lastly, the Exchange currently offers the Tape C Quoting Tier under which a Member may receive an additive rebate of $0.0002 per share for a qualifying Member's executions of Added Displayed Volume (other than Retail Orders) in Tape C securities priced over $1.00 per share by achieving an NBBO Time of at least 50% in an average of at least 500 Tape C securities per trading day during the month. Now, the Exchange proposes to reduce the additive rebate provided under the Tape C Quoting Tier to $0.0001 per share. ¹⁹ ( printed page 36029) The Exchange is not proposing to change the criteria required to qualify for Tape C Quoting Tier.

The Exchange believes that the proposed reduction of the additive rebate under the Tape C Quoting Tier ( i.e., by $0.0001 per share) represents a modest reduction and that the proposed additive rebate under Tape C Quoting Tier remains commensurate with the required criteria under such tier and is reasonably related to the market quality benefits that the tier is designed to achieve.

2. Statutory Basis

The Exchange believes that the proposed rule change is consistent with the provisions of Section 6 of the Act,^[20] in general, and with Sections 6(b)(4) and 6(b)(5) of the Act,^[21] in particular, in that it provides for the equitable allocation of reasonable dues, fees and other charges among its Members and other persons using its facilities and is not designed to permit unfair discrimination between customers, issuers, brokers, or dealers.

As discussed above, the Exchange operates in a highly fragmented and competitive market in which market participants can readily direct order flow to competing venues if they deem fee levels at a particular venue to be excessive or incentives to be insufficient, and the Exchange represents only a small percentage of the overall market. The Commission and the courts have repeatedly expressed their preference for competition over regulatory intervention in determining prices, products, and services in the securities markets. In Regulation NMS, the Commission highlighted the importance of market forces in determining prices and SRO revenues and also recognized that current regulation of the market system “has been remarkably successful in promoting market competition in its broader forms that are most important to investors and listed companies.” ^[22]

The Exchange believes that the ever-shifting market share among the exchanges from month to month demonstrates that market participants can shift order flow or discontinue use of certain categories of products, in response to new or different pricing structures being introduced into the market. Accordingly, competitive forces constrain the Exchange's transaction fees and rebates, and market participants can readily trade on competing venues if they deem pricing levels at those other venues to be more favorable. The Exchange believes the proposal reflects a reasonable and competitive pricing structure designed to incentivize market participants to direct additional order flow, including displayed and non-displayed, liquidity-adding orders to the Exchange, both which the Exchange believes would promote price discovery and enhance liquidity and market quality on the Exchange to the benefit of all Members and market participants.

The Exchange believes that the proposed changes to reduce the base rebates for executions of Added Price Improved Volume, Added Non-Midpoint Non-Displayed Volume, and Added Midpoint Non-Displayed Volume, are reasonable because the amended rebates remain in line with or are greater than the rebates provided by at least one other exchange for executions of the same type.^[23] The Exchange also believes the reduced rebates are equitable and not unfairly discriminatory, as such rebates will apply equally to all Members of the Exchange.

The Exchange notes that volume and quoting-based incentives (such as tiers) have been widely adopted by exchanges, including the Exchange, and are reasonable, equitable and not unfairly discriminatory because they are open to all members on an equal basis and provide additional benefits that are reasonably related to the value of an exchange's market quality associated with higher levels of market activity, such as higher levels of liquidity provision and/or growth patterns, and the introduction of higher volumes of orders into the price and volume discovery process. The Exchange believes that the Tape A and Tape C Quoting Tiers, each as modified by the proposed changes herein, as well as the adoption of Non-Display Add Tier 2, are reasonable, equitable and not unfairly discriminatory, as such tiers will continue to provide Members with an incremental incentive to achieve certain volume thresholds on the Exchange, are available to all Members on an equal basis, and, as described above, are designed to encourage Members to maintain or increase their order flow, including in the form of displayed, and/or non-displayed, liquidity-adding orders to the Exchange, thereby contributing to a deeper, more liquid and well balanced market ecosystem on the Exchange to the benefit of all Members and market participants.

The Exchange believes the proposed change to eliminate the Display-Price Sliding Tier 1 is reasonable because it would enable to the Exchange to redirect the associated resources and funding into other incentives and tiers, and the Exchange is not required to maintain such incentive or provide Members any opportunities to receive enhanced rebates. The Exchange believes the proposal to eliminate such incentive is also equitable and not unfairly discriminatory because it applies equally to all Members, in that the incentive would no longer be available for any Member.

For the reasons discussed above, the Exchange submits that the proposal satisfies the requirements of Sections 6(b)(4) and 6(b)(5) of the Act ^[24] in that it provides for the equitable allocation of reasonable dues, fees and other charges among its Members and other persons using its facilities and is not designed to unfairly discriminate between customers, issuers, brokers, or dealers. As described more fully below in the Exchange's statement regarding the burden on competition, the Exchange believes that its transaction pricing is subject to significant competitive forces, and that the proposed rebates described herein are appropriate to address such forces.

B. Self-Regulatory Organization's Statement on Burden on Competition

The Exchange does not believe that the proposal will result in any burden on competition that is not necessary or appropriate in furtherance of the purposes of the Act. Instead, as discussed above, the proposal is intended to incentivize market participants to direct additional order flow to the Exchange, thereby enhancing liquidity and market quality on the Exchange to the benefit of all Members and market participants. As a result, the Exchange believes the proposal would enhance its competitiveness as a market that attracts actionable orders, thereby making it a more desirable destination venue for its customers. For these reasons, the Exchange believes that the proposal furthers the Commission's goal in adopting Regulation NMS of fostering competition among orders, which promotes “more efficient pricing of ( printed page 36030) individual stocks for all types of orders, large and small.” ^[25]

Intramarket Competition

As discussed above, the Exchange believes that the proposal would incentivize Members to submit additional order flow, including displayed and non-displayed, liquidity-adding orders to the Exchange, thereby enhancing liquidity and market quality on the Exchange to the benefit of all Members, as well as enhancing the attractiveness of the Exchange as a trading venue, which the Exchange believes, in turn, would continue to encourage market participants to direct additional order flow to the Exchange. Greater liquidity benefits all Members by providing more trading opportunities and encourages Members to send additional orders to the Exchange, thereby contributing to robust levels of liquidity, which benefits all market participants.

The Exchange does not believe that the proposed changes to reduce the base rebates for executions of Added Price Improved Volume, Added Non-Midpoint Non-Displayed Volume, and Added Midpoint Non-Displayed Volume would impose any burden on intramarket competition because such changes will apply to all Members uniformly in that the proposed reduced rebates for such executions would be the rebates applicable to all Members, and the opportunity to qualify for enhanced rebates, as applicable, is available to all Members. Further, the opportunity to qualify for the newly proposed Non-Display add Tier 2, and thus receive the proposed enhanced rebate for executions of Added Non-Displayed Volume under such tier, and the opportunity to qualify for the reduced additive rebates under the Tape A and Tape C Quoting Tiers, respectively, would be available to all Members that meet the associated volume or quoting requirements in any month. Additionally, as noted above, the elimination of the Display-Price Sliding Tier will apply to all Members equally. For the foregoing reasons, the Exchange believes the proposed changes would not impose any burden on intramarket competition that is not necessary or appropriate in furtherance of the purposes of the Act.

Intermarket Competition

As noted above, the Exchange operates in a highly competitive market in which market participants can readily direct order flow to competing venues if they deem fee levels at a particular venue to be excessive or incentives to be insufficient. Members have numerous alternative venues that they may participate on and direct their order flow to, including 17 other equities exchanges and numerous alternative trading systems and other off-exchange venues. As noted above, no single registered equities exchange currently has more than approximately 14% of the total market share of executed volume of equities trading. Thus, in such a low-concentrated and highly competitive market, no single equities exchange possesses significant pricing power in the execution of order flow. Moreover, the Exchange believes that the ever-shifting market share among the exchanges from month to month demonstrates that market participants can shift order flow or reduce use of certain categories of products, in response to new or different pricing structures being introduced into the market. Accordingly, competitive forces constrain the Exchange's transaction fees and rebates, including with respect to Added Non-Displayed Volume and Added Displayed Tape A and Tape C volume and market participants can readily choose to send their orders to other exchange and off-exchange venues if they deem fee levels at those other venues to be more favorable. As described above, the proposed changes represent a competitive proposal through which the Exchange is seeking to generate additional revenue with respect to its transaction pricing and to encourage the submission of additional order flow to the Exchange through volume and quoting-based tiers, which have been widely adopted by exchanges, including the Exchange. Accordingly, the Exchange believes the proposal would not burden, but rather promote, intermarket competition by enabling it to better compete with other exchanges that offer similar pricing incentives to market participants.

Additionally, the Commission has repeatedly expressed its preference for competition over regulatory intervention in determining prices, products, and services in the securities markets. Specifically, in Regulation NMS, the Commission highlighted the importance of market forces in determining prices and SRO revenues and, also, recognized that current regulation of the market system “has been remarkably successful in promoting market competition in its broader forms that are most important to investors and listed companies.” ^[26] The fact that this market is competitive has also long been recognized by the courts. In NetCoalition v. SEC, the D.C. Circuit stated as follows: “[n]o one disputes that competition for order flow is `fierce.' . . . As the SEC explained, `[i]n the U.S. national market system, buyers and sellers of securities, and the broker-dealers that act as their order-routing agents, have a wide range of choices of where to route orders for execution'; [and] `no exchange can afford to take its market share percentages for granted' because `no exchange possesses a monopoly, regulatory or otherwise, in the execution of order flow from broker dealers'. . . .”.^[27] Accordingly, the Exchange does not believe its proposed pricing changes impose any burden on competition that is not necessary or appropriate in furtherance of the purposes of the Act.

C. Self-Regulatory Organization's Statement on Comments on the Proposed Rule Change Received From Members, Participants, or Others

The Exchange neither solicited nor received comments on the proposed rule change.

III. Date of Effectiveness of the Proposed Rule Change and Timing for Commission Action

The foregoing rule change has become effective pursuant to Section 19(b)(3)(A)(ii) of the Act ^[28] and Rule 19b-4(f)(2) ^[29] thereunder.

At any time within 60 days of the filing of the proposed rule change, the Commission summarily may temporarily suspend such rule change if it appears to the Commission that such action is necessary or appropriate in the public interest, for the protection of investors, or otherwise in furtherance of the purposes of the Act. If the Commission takes such action, the Commission shall institute proceedings to determine whether the proposed rule change should be approved or disapproved.

IV. Solicitation of Comments

Interested persons are invited to submit written data, views and arguments concerning the foregoing, including whether the proposed rule change is consistent with the Act. Comments may be submitted by any of the following methods: ( printed page 36031)

Electronic Comments

• Use the Commission's internet comment form (https://www.sec.gov/​rules/​sro.shtml); or
• Send an email torule-comments@sec.gov. Please include file number SR-MEMX-2026-16 on the subject line.

Paper Comments

• Send paper comments in triplicate to Secretary, Securities and Exchange Commission, 100 F Street NE, Washington, DC 20549-1090.

All submissions should refer to file number SR-MEMX-2026-16. This file number should be included on the subject line if email is used. To help the Commission process and review your comments more efficiently, please use only one method. The Commission will post all comments on the Commission's internet website ( https://www.sec.gov/​rules/​sro.shtml). Copies of the filing also will be available for inspection and copying at the principal office of the Exchange. Do not include personal identifiable information in submissions; you should submit only information that you wish to make available publicly. We may redact in part or withhold entirely from publication submitted material that is obscene or subject to copyright protection. All submissions should refer to file number SR-MEMX-2026-16 and should be submitted on or before July 6, 2026.