[Federal Register Volume 88, Number 71 (Thursday, April 13, 2023)]
[Notices]
[Pages 22498-22506]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07733]


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SECURITIES AND EXCHANGE COMMISSION

[Release No. 34-97263; File No. SR-NASDAQ-2022-079]


Self-Regulatory Organizations; The Nasdaq Stock Market LLC; 
Notice of Filing of Amendment No. 1 and Order Instituting Proceedings 
To Determine Whether To Approve or Disapprove a Proposed Rule Change, 
as Modified by Amendment No. 1, To Amend Rules 4702(b)(14) and (b)(15) 
Concerning Dynamic M-ELO Holding Periods

April 7, 2023.
    On December 21, 2022, The Nasdaq Stock Market LLC (``Nasdaq'' or 
``Exchange'') filed with the Securities and Exchange Commission 
(``Commission''), pursuant to Section 19(b)(1) of the Securities 
Exchange Act of 1934 (``Act'') \1\ and Rule 19b-4 thereunder,\2\ a 
proposed rule change to replace the static holding period requirements 
for Midpoint Extended Life Orders and Midpoint Extended Life Orders 
Plus Continuous Book with dynamic holding periods. The proposed rule 
change was published for comment in the Federal Register on January 10, 
2023.\3\ On February 22, 2023, pursuant to Section 19(b)(2) of the 
Act,\4\ the Commission designated a longer period within which to 
approve the proposed rule change, disapprove the proposed rule change, 
or institute proceedings to determine whether to disapprove the 
proposed rule change.\5\ On March 9, 2023, the Exchange filed Amendment 
No.1 to the proposed rule change, which amended and superseded the 
proposed rule change as originally filed.\6\ The

[[Page 22499]]

Commission received two comments on the proposal, and the Exchange 
submitted a response to comments when it filed Amendment No. 1.\7\ The 
Commission is publishing this notice and order to solicit comments on 
the proposed rule change, as modified by Amendment No. 1, from 
interested persons and to institute proceedings pursuant to Section 
19(b)(2)(B) of the Act \8\ to determine whether to approve or 
disapprove the proposed rule change, as modified by Amendment No. 1.
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    \1\ 15 U.S.C. 78s(b)(1).
    \2\ 17 CFR 240.19b-4.
    \3\ See Securities Exchange Act Release No. 92844 (January 4, 
2023), 88 FR 1438.
    \4\ 15 U.S.C. 78s(b)(2).
    \5\ See Securities Exchange Act Release No. 96963, 88 FR 12710 
(February 28, 2023).
    \6\ In Amendment No. 1, the Exchange (i) included additional 
information regarding the data used by its model, including a list 
of the 142 categories of data points; (ii) described its model 
retraining process; (iii) added information regarding the types of 
modifications for which it would request Commission approval; (iv) 
indicated it would regularly publish data regarding M-ELO and M-
ELO+CB performance and holding period changes; and (v) stated its 
model would constitute an established, non-discriminatory method and 
would operate according to pre-disclosed rules and objectives 
without the exercise of discretion. When it submitted Amendment No. 
1, the Exchange also submitted it as a comment letter to the filing, 
available at: https://www.sec.gov/comments/sr-nasdaq-2022-079/srnasdaq2022079-20159016-327215.pdf.
    \7\ Comments and the Exchange's response to comments are 
available at: https://www.sec.gov/comments/sr-nasdaq-2022-079/srnasdaq2022079.htm.
    \8\ 15 U.S.C. 78s(b)(2)(B).
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I. Self-Regulatory Organization's Statement of the Terms of Substance 
of the Proposed Rule Change

    The Exchange proposes to amend Rules 4702(b)(14) and (b)(15) of the 
Exchange's Rulebook to replace the static holding period requirements 
for Midpoint Extended Life Orders and Midpoint Extended Life Orders 
Plus Continuous Book with dynamic holding periods. Amendment No. 1 
supersedes the original filing in its entirety.
    The text of the proposed rule change is available on the Exchange's 
website at https://listingcenter.nasdaq.com/rulebook/nasdaq/rules, at 
the principal office of the Exchange, and at the Commission's Public 
Reference Room.

II. Self-Regulatory Organization's Statement of 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 Rules 4702(b)(14) and (15) of the 
Exchange's Rulebook to replace the static 10 millisecond holding period 
requirements for its Midpoint Extended Life Order (``M-ELO'') and 
Midpoint Extended Life Order Plus Continuous Book (``M-ELO+CB'') Order 
Types with dynamic holding periods (``Dynamic M-ELO and M-ELO+CB'' or 
collectively, ``Dynamic M-ELO'').
Background
    In 2018, the Exchange introduced the M-ELO, which is a Non-
Displayed Order priced at the Midpoint between the National Best Bid 
and Offer (``NBBO'') and which is eligible for execution only against 
other eligible M-ELOs and only after a minimum of one-half second 
passes from the time that the System accepts the order (the ``Holding 
Period'').\9\ In 2019, the Exchange introduced the M-ELO+CB, which 
closely resembles the M-ELO, except that a M-ELO+CB may execute at the 
midpoint of the NBBO, not only against other eligible M-ELOs (and M-
ELO+CBs), but also against Non-Displayed Orders with Midpoint Pegging 
and Midpoint Peg Post-Only Orders (``Midpoint Orders'') that rest on 
the Continuous Book for at least one-half second and have Trade Now 
enabled.\10\
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    \9\ See Securities Exchange Act Release No. 34-82825 (March 7, 
2018), 83 FR 10937 (March 13, 2018) (SR-NASDAQ-2017-074) (``M-ELO 
Approval Order'').
    \10\ See Securities Exchange Act Release No. 34-86938 (September 
11, 2019), 84 FR 48978 (September 17, 2019) (SR-NASDAQ-2019-048) 
(``M-ELO+CB Approval Order'').
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    When the Exchange designed M-ELO, it originally set the length of 
the Holding Period at one-half second because it determined that this 
time period would be sufficient to ensure that likeminded investors 
would interact only with each other, and with minimal market impacts. 
The Exchange believed that the longer length of the M-ELO Holding 
Period and its simplicity in design would provide greater protection 
for participants than they could achieve through competing delay 
mechanisms.
    In 2020, however, the Exchange shortened the length of the Holding 
Period to 10 milliseconds.\11\ The Exchange did so after studying two 
years of actual use and performance of M-ELOs, as well as customer 
feedback. That is, the Exchange came to understand that, while users of 
M-ELO and M-ELO+CB are less concerned with achieving rapid executions 
of their Orders than are other participants, they are not indifferent 
about the length of time in which their M-ELOs and M-ELO+CBs must wait 
before they are eligible for execution. Indeed, participants informed 
the Exchange that in certain circumstances, such as when they sought to 
trade symbols that on average had a lower time-to-execution than a 
half-second, they were reticent to enter M-ELOs or M-ELO+CBs. They 
indicated that the associated Holding Periods for these Order Types 
were longer than necessary to achieve the desired protections and that, 
during the residual portion of the Holding Periods, they risked losing 
out on favorable execution opportunities that would otherwise be 
available to them had they placed a non-MELO order.
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    \11\ See Securities Exchange Act Release No. 34-88743 (April 24, 
2020), 85 FR 24068 (April 30, 2020) (SR-NASDAQ-2020-011) (``M-ELO 
Timer Approval Order'').
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    Based upon this feedback, the Exchange studied the potential 
effects of reducing the length of the Holding Periods for both M-ELOs 
and M-ELO+CBs (as well as for Midpoint Orders that would execute 
against M-ELO+CBs). Ultimately, the Exchange determined that it could 
reduce the Holding Periods to 10 milliseconds without compromising the 
protective power that M-ELO and M-ELO+CB are intended to provide to 
participants and investors.\12\ Thus, the Exchange determined that 
shortening the Holding Periods to 10 milliseconds for M-ELOs and M-
ELO+CBs would increase the efficacy of the mechanism while not 
undermining the power of those Order Types to fulfill their underlying 
purpose of minimizing market impacts. At the same time, the Exchange 
determined

[[Page 22500]]

that a reduction in the Holding Periods to 10 milliseconds would 
dramatically add to the circumstances in which M-ELOs and M-ELO+CBs 
would be useful to participants. In its M-ELO Timer Approval Order, the 
Commission agreed with the Exchange:
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    \12\ The Exchange examined each of its historical M-ELO 
executions to determine at what Midpoints of the NBBO the M-ELOs 
would have executed if their Holding Periods had been shorter than 
one-half second (500 milliseconds). After examining the historical 
effects of shorter Holding Periods of between 10 milliseconds and 
400 milliseconds, the Exchange determined that a reduction of the M-
ELO Holding Period to as short as 10 milliseconds would have caused 
an average impact on mark-outs of only 0.10 basis points (across all 
symbols). In other words, compared to the execution price of an 
average M-ELO with a one-half second Holding Period, the Exchange 
found that a M-ELO with a 10 millisecond Holding Period would have 
had an average post-execution impact that was only a tenth of a 
basis point per share--a difference in protective effect that is 
immaterial. See Nasdaq, ``The Midpoint Extended Life Order (M-ELO); 
M-ELO Holding Period,'' available at https://www.nasdaq.com/articles/the-midpoint-extended-life-order-m-elo%3A-m-elo-holding-period-2020-02-13 (analyzing effects of shortened Holding Periods on 
M-ELO performance).
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    The Commission notes that, with the proposed ten-millisecond 
Holding Period and Resting Period, M-ELOs and M-ELO+CBs would continue 
to be optional order types that are available to investors with longer 
investment time horizons, including institutional investors. The 
Commission also believes that the proposal could make M-ELOs and M-
ELO+CBs more attractive for securities that on average have a time-to-
execution of less than one-half second and, for investors who currently 
do not use M-ELOs and M-ELO+CBs for these securities, provide optional 
order types that could enhance their ability to participate effectively 
on the Exchange. The Commission notes that, if market participants 
determine that the proposal would make M-ELOs and M-ELO+CBs less 
attractive for their particular investment objectives, such market 
participants may elect to reduce or eliminate their use of these 
optional order types. Moreover, as noted above, the Exchange will 
continue to conduct real-time surveillance to monitor the use of M-ELOs 
and M-ELO+CBs to ensure that such usage remains appropriately tied to 
the intent of the order types. If, as a result of such surveillance, 
the Exchange determines that the shortened Holding Period does not 
serve its intended purpose or adversely impacts market quality, the 
Exchange would seek to make further recalibrations.\13\
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    \13\ M-ELO Timer Approval Order, supra, at 85 FR 24069.
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    For similar reasons and with even better potential results for 
participants, the Exchange now proposes to further refine the length of 
the Holding Periods for M-ELOs and M-ELO+CBs, this time through the 
application of innovative and patent pending machine learning 
technology.
Dynamic M-ELO
    After receiving feedback from participants that even 10 millisecond 
Holding Periods for M-ELO and M-ELO+CB may, at times, exceed what is 
necessary to accomplish the underlying intent of these Order Types, the 
Exchange began to experiment with making further refinements to the 
duration of the Holding Periods. Ultimately, the Exchange concluded 
that shorter Holding Periods could achieve the same, if not better 
results for participants in terms of mark-outs, but not in all 
circumstances. That is, where prices of the underlying securities are 
stable, and not subject to imminent unfavorable changes, M-ELOs and M-
ELO+CBs face lower risks of confronting spread-crossing orders, such 
that shorter Holding Periods could suffice to protect M-ELOs and M-
ELO+CB from such orders. In periods of heightened price volatility, 
however, M-ELOs and M-ELO+CBs also face heightened risks, such that 
longer Holding Periods would continue to be beneficial in protecting M-
ELOs and M-ELO+CBs from such risks. Thus, the Exchange determined that 
another across-the-board reduction of the static 10 millisecond Holding 
Periods would be sub-optimal because it could impact the performance of 
the M-ELO and M-ELO+CB Order Types during periods of heightened 
volatility.
    In light of these observations, the Exchange tasked its artificial 
intelligence and machine learning laboratory (the ``AI Core Development 
Group'') to explore whether it could employ these innovative 
technologies to optimize the length of M-ELO and M-ELO+CB Holding 
Periods during various states of price volatility, and then to vary the 
lengths of the Holding Periods dynamically during the lifecycles of M-
ELOs and M-ELO+CBs, with the objectives of improving the performance of 
these Order Types while also further reducing opportunity costs.
    As the Exchange explains in greater depth in the attached [sic] 
white paper,\14\ the AI Core Development Group proceeded to develop an 
artificial intelligence-based timer control system that will achieve 
these objectives.\15\ The AI Core Development Group did so by using 
reinforcement learning techniques--machine learning paradigms which 
develop optimal solutions to problems over time by taking actions to 
solve them, generating feedback on the results of such actions, 
applying that feedback to direct and improve the next round of 
solutions, and then repeating the feedback loop until the paradigm 
achieves optimized solutions.
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    \14\ See Diana Kafkes et al., ``Applying Artificial Intelligence 
& Reinforcement Learning Methods Towards Improving Execution 
Outcomes,'' SSRN, October 19, 2022, available at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4243985 (attached hereto 
[sic] as Exhibit 3(a)) (the ``White Paper'').
    \15\ Although the AI Core Development Group acknowledges that an 
optimal Holding Period would update with every incoming order, it 
determined that training a reinforcement learning model on every 
order would be too difficult to program and too difficult to 
implement given the nanosecond latency requirements of the Exchange. 
The Group then investigated more feasible update cadences and 
determined the point at which optimal outcomes were best balanced 
with the level of programming and implementation difficulty to be 
between 15 and 30 second updates. Ultimately, the Group chose a 30 
second update cadence to give the model the greatest opportunity to 
learn between potential actions.
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    In this instance, the AI Core Development Group applied 
reinforcement learning techniques to a simulation of the M-ELO Book 
that it constructed using a representative data set from the first 
quarter of 2022 (the ``Training Period''). The Training Period data 
consisted of 380 out of the 6,257 symbols on the M-ELO Book (accounting 
for approximately 67 percent of M-ELO volume). The symbols chosen 
reflect both actively-traded and thinly-traded securities, and both 
low-priced and high-priced securities.
    The AI Core Development Group then developed a machine learning 
model and applied it to the Training Period data. The Group programmed 
the model to value the achievement of higher fill rates or lower mark-
outs than that which occurred in a historical simulation of M-ELOs and 
M-ELO+CBs involving the Training Period data.\16\ The Group then 
programmed the model to seek to achieve its goals by taking one of five 
possible actions with respect to the duration of the Holding Periods at 
30 second intervals \17\ for each symbol during each trading day of the 
Training Period. That is, at each 30 second internal, the model 
evaluated market conditions for each symbol over the prior 30 second 
period and either kept the Holding Periods the same, increased/
decreased them by 0.25 milliseconds, or increased/decreased them by 
0.50 milliseconds.\18\ After each decision-making round, the model 
utilized the results to inform its actions at the next 30 second 
increment.
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    \16\ As the White Paper explains, the Group developed a model to 
simulate activity on the Exchange involving M-ELOs and M-ELO+CBs 
during the Training Period. See White Paper, supra, at 10.
    \17\ See id.
    \18\ The AI Core Development Group experimented with a range of 
permissible Holding Period durations. Ultimately, it concluded that 
it could produce better outcomes for M-ELO and M-ELO+CB participants 
than the existing approach using Holding Periods as low as 0.25 
milliseconds and as high as 2.5 milliseconds, under normal market 
conditions.
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    In making its decisions, the model (again, drawing upon a 
combination of historical SIP and M-ELO-specific data) considered 142 
categories of data points.\19\ A confluence of data points

[[Page 22501]]

that correlated with an increase in volatility tended to cause the 
model to increase the durations of Holding Periods, including increases 
in the standard deviation of NBBO prices, the number of unique 
participants placing sell orders on M-ELO and M-ELO+CB, and the volume-
weighted average of the NBBO spread. Conversely, a confluence of data 
points that correlated with greater price stability tended to cause the 
model to decrease the durations of Holding periods, such as an increase 
in the median and max number of shares per trade and the number of 
resting bids left in the M-ELO and M-ELO+CB Book.
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    \19\ Nasdaq attaches [sic] a full list of these data elements 
(attached hereto [sic] as ``Exhibit 3(b)''), along with an 
observation of the strength of the correlations that currently exist 
between changes to those data values and decisions the system makes 
to set the duration of Holding Periods at any given time. See also 
White Paper, supra, at 31, for a description of these features.
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    The AI Core Development Team produced variations of its model that 
prioritized achievement of the lowest mark-outs, the highest fill 
rates, and a blend of these two objectives.\20\ Through a process of 
learning and experimentation involving a combination of historical and 
simulated data, the AI Core Development Group settled on a Dynamic M-
ELO model that achieved substantial simulated performance improvements 
for users of M-ELO and M-ELO+CB--both in terms of mark-outs and fill 
rates--as compared to the static 10 millisecond Holding Periods. As the 
White Paper explains in greater detail, Dynamic M-ELO yielded an 
average combined volume-weighted (simulated) improvement of 31.7 
percent, including a 20.3 percent increase in fill rates and a 11.4 
percent reduction in mark-outs.\21\ The White Paper provides a more 
fulsome explanation of these improvements.\22\
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    \20\ The AI Core Development Group also applied to the model a 
paradigm called ``retraining'' to combat the degradation of model 
performance that can otherwise occur as the reference data it uses 
for initial comparison becomes stale. Finally, the AI Core 
Development group added a stability protection mechanism to the 
model to provide maximum production to participants in the event 
that the model observes extraordinary levels of instability in the 
National Best Bid and Offer during the prior three seconds as 
compared to reference data. When the model detects such instability, 
it is programmed to increase the length of the Holding Period to 12 
milliseconds for a period of 750 milliseconds.
    \21\ See White Paper, supra, at 22.
    \22\ See id.
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    Based upon these exciting results, the Exchange now proposes to 
amend Rule 4702(b)(14) and (15) to replace the static 10 millisecond 
timers applicable to M-ELO and M-ELO+CB with Dynamic M-ELO Holding 
Periods. Using the Exchange's proprietary and patent pending 
technology, the Dynamic M-ELO system will evaluate and, as it deems 
necessary, adjust the length of the Holding Periods for each symbol 
comprising M-ELOs and M-ELO+CBs (and Midpoint Orders on the Continuous 
Book that opt to interact with M-ELO+CBs after resting on the Book) 
every 30 seconds throughout the Market Hours (each such 30 second 
interval, a ``Change Event''). In so doing, Dynamic M-ELO will help 
participants to achieve a more optimized blend of the underlying 
purposes of the M-ELO and M-ELO+CB Order Types: protection against 
adverse selection (low mark-outs) without sacrificing opportunities to 
achieve high-quality executions (high fill rates).
    A proposed M-ELO or M-ELO+CB with a Dynamic Holding Period will 
operate as follows. At the outset of Market Hours (approximately 
9:30:00 a.m.), the Exchange will impose initial Holding Periods of 1.25 
milliseconds for M-ELOs and M-ELO+CBs in all symbols. Thereafter, 
Holding Periods for a given symbol will become eligible to change 
dynamically from the initial duration beginning at 9:30:30 a.m. and 
then at 30 second intervals thereafter during Market Hours. The 
Exchange will then apply to the M-ELO or M-ELO+CB Order a Holding 
Period that is of the duration that prevailed at the time of entry. For 
example, if participant A enters a M-ELO for symbol XYZ at 9:30:25 
a.m., then Holding Period for that M-ELO will be 1.25 milliseconds. If 
at 9:30:30:00 a.m., the System decides to lower the duration of the 
Holding Period by 0.50 milliseconds, and then participant B enters a M-
ELO for symbol XYZ at 9:30:45 a.m., then the System will assign a 0.75 
millisecond Holding Period to participant B's M-ELO. To be clear, the 
System will determine Dynamic M-ELO Holding Periods independently for 
M-ELOs and M-ELO+CBs in each symbol.
    During normal market conditions, the range of potential Holding 
Period durations for M-ELOs and M-ELO+CBs will be between 0.25-2.50 
milliseconds, with the Holding Period duration being eligible to change 
by increments of either 0.25 or 0.50 milliseconds at each Change Event. 
Thus, if the Holding Period for a M-ELO in symbol XYZ is set at 0.75 
milliseconds at 2:22:11 p.m., and at 2:22:41 p.m., the System 
determines to increase the duration of the Holding Period, it may do so 
only by 0.25 or 0.50 milliseconds during that event.
    When a Change Event occurs, and the System determines to adjust the 
duration of a Holding Period for a symbol, that adjustment will apply, 
not only to all M-ELOs and M-ELO+CBs for that symbol entered within the 
30 second period after the Change Event occurs, but also to M-ELOs and 
M-ELO+CBs entered prior to the Change Event with unexpired Holding 
Periods (with applicability retroactive to the time of Order 
acceptance). Thus, if a participant enters a M-ELO in symbol XYZ at 
1:14:299 p.m., and the prevailing Holding Period applicable to that M-
ELO is 2 milliseconds, and at 1:14:30 p.m., the System modifies the 
Holding Period to be 1.5 milliseconds, then the M-ELO will become 
eligible to execute at 1:14:3005 p.m. This is the case because the M-
ELO will have already expended 1 millisecond of its Holding Period as 
of the time of the Change Event; thereafter, the M-ELO will need to 
rest only another 0.5 milliseconds to become eligible to execute under 
the new 1.5 millisecond Holding Period (as measured from 1:14:299 
p.m.). This last feature ensures that the M-ELO Book maintains time 
priority among M-ELOs and M-ELO+CBs in a dynamic environment. That is, 
it ensures that no M-ELO or M-ELO+CB with an unexpired Holding Period 
at the time of a Change Event will end up becoming eligible to execute 
later than a M-ELO entered after the Change Event which has a shorter 
Holding Period applicable to it.
    If at any time, the System detects extraordinary instability in a 
symbol, then the System will activate a ``stability protection 
mechanism'' to provide an extra layer of protection to M-ELO and M-ELO 
users from the heightened risks of adverse selection that exists during 
such periods of instability.\23\ The stability protection mechanism 
will override the prevailing Holding Periods for M-ELOs and M-ELO+CBs 
in a symbol experiencing extraordinary instability and immediately 
increase the duration of those Holding Periods to 12 milliseconds for a 
period of 750 milliseconds. The System may activate the stability 
protection mechanism even between Change Events. The System will 
evaluate, at each NBBO update, whether market conditions remain 
extraordinarily unstable and, if so, it will restart the 750 
millisecond Stability Protected Period and maintain the 12

[[Page 22502]]

millisecond Holding Period until conditions stabilize. Once the System 
determines that market conditions have stabilized (i.e., all 
measurements for the symbol are at or below the threshold value 
throughout the duration of the prevailing Stability Protected Period), 
the System will revert the duration of the Holding Periods to that 
which prevailed as of the Change Event that occurred immediately prior 
to the activation of the stability protection mechanism or, if the 
stability protection mechanism was active when a Change Event occurred, 
to the duration selected at the immediately preceding Change Event. The 
System will then proceed to reevaluate the duration of the Holding 
Periods as per the regular schedule of Change Events.
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    \23\ For purposes of this Rule, the System determines that 
``extraordinary instability'' for a symbol exists through 
observations it makes following every change in the NBBO for that 
symbol that occurs during the trading day. When the NBBO changes, 
the System looks back at the prior three seconds of trading and 
measures the difference between the highest and the lowest NBBO 
midpoint values that occurred during that period, and then it 
compares that measurement to a threshold value for the symbol. The 
System concludes that extraordinary instability exists for a symbol 
if the measurement exceeds the threshold value. The threshold value 
for a symbol, in turn, is the difference between the highest and the 
lowest NBBO midpoint values for the symbol that, if applied to its 
trading activity during the prior trading day, would have caused the 
System to deem trading in the symbol to be extraordinarily unstable 
for as close to one percent of that day as possible.
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    The following is an illustration of the operation of the stability 
protection mechanism. At 11:10:04 a.m., the prevailing Holding Period 
for M-ELOs in symbol XYZ is 1.5 milliseconds. At the same time, the 
NBBO for symbol XYZ updates. The System looks back at the prior three 
seconds of trading in symbol XYZ and finds that during that period, the 
highest observed NBBO midpoint was $10.05, and the lowest was $10.00, 
such that the difference between these two values is a range of $0.05. 
The System then looks back at trading behavior for symbol XYZ during 
the immediately preceding trading day. In doing so, the System 
calculates the value of the threshold that would have caused the symbol 
to be deemed extraordinarily unstable for one percent of the trading 
day; the System determines that this threshold value is a range of 
$0.03. The System then compares the $0.03 threshold to its measurement 
of the prior three seconds of NBBO changes ($0.05), and concludes that 
over these past three seconds, the symbol is extraordinarily unstable. 
Accordingly, the System activates the stability protection mechanism 
and the Holding Period for M-ELOs in symbol XYZ immediately increases 
to 12 milliseconds for a period of 750 milliseconds. However, 5 
milliseconds after the Stability Protection Period commences, the NBBO 
updates again, thus prompting the System to repeat its assessment of 
the stability of the symbol in light of the update. This reassessment 
reveals that the symbol remains unstable, such that a new Stability 
Protection Period of 750 milliseconds begins at that time (overriding 
the pre-existing Period). Over the course of this new Stability 
Protection Period, the NBBO shifts two more times, but each of the 
ensuing reassessments indicate that the NBBO ranges for the symbol have 
fallen below the $0.03 threshold. The Stability Protection Period 
elapses 750 milliseconds after it began with the symbol remaining 
stable. Thus, the Holding Period reverts to 1.5 milliseconds.
    If the Exchange halts trading in a symbol, then upon resumption of 
trading, any new M-ELO or M-ELO+CB in that symbol and any pending M-ELO 
or M-ELO+CB in that symbol with an unexpired Holding Period will be 
subject to a new 12 milliseconds Holding Period (running from the time 
when trading resumes) until the next scheduled Change Event, at which 
point the System may determine to adjust that Holding Period to a 
duration within the range applicable under normal market 
conditions.\24\ If, however, the System determines that extraordinary 
instability in the symbol exists, it will instead determine to activate 
the stability protection mechanism and maintain the duration of the 
Holding Period at 12 milliseconds for another 750 milliseconds. This 
design will help to ensure that M-ELOs and M-ELO+CBs receive added 
protection coming out of halt conditions.\25\
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    \24\ Prior to commencement of a new 12 millisecond Holding 
Period for a new or pending M-ELO or M-ELO+CB following a Halt, the 
System will first determine whether the M-ELO or M-ELO+CB is or 
remains eligible for execution. That is, the Holding Period will 
commence only if, upon commencement of trading following the Halt, 
the midpoint price for the Order is within the limit set by the 
participant. If not, the System will hold the Order until the 
midpoint falls within the limit set by the participant, at which 
time the 12 millisecond Holding Period will commence.
    \25\ Also as a safeguard, the System will apply a default 
Holding Period of 12 milliseconds to a M-ELO or M-ELO+CB if ever it 
fails to receive a signal during a Change Event as to whether the 
System should adjust or maintain the duration of the prevailing 
Holding Period. The System will continue to apply the default 12 
millisecond Holding Period until the next Change Event where the 
signal is restored and the System is able to act dynamically again.
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    The Exchange notes that same dynamic process described above will 
also apply to and govern the time periods during which Midpoint Orders 
on the Continuous Book must rest before they will become eligible to 
interact with M-ELO+CBs (provided that participants have opted for 
their Midpoint Orders to interact with M-ELO+CBs). Thus, the same 
Holding Period duration that the System sets for a M-ELO+CB in a symbol 
during Regular Market Hours will also be the length of time that a 
Midpoint Order must rest on the Continuous Book must rest before it may 
interact with a M-ELO+CB.
    Apart from these impacts of Dynamic Holding Periods, M-ELOs and M-
ELO+CBs will continue to behave as they do now in all respects, and as 
set forth in Rules 4702(b)(14) and (15).
    It is important to note that within the parameters discussed herein 
and in the White Paper, the Exchange will continue to re-train Dynamic 
M-ELO and M-ELO+CB on a weekly basis (outside of market hours) so that 
the model will continue to learn from and act upon the basis of more 
recent SIP and M-ELO book data sets, and further improve its 
performance over time. The retraining process should not result in 
dramatic or unpredictable changes to the behavior of Dynamic M-ELO. The 
retraining process will not retrain the model from scratch each week; 
rather, it will retain the model's existing data inputs, knowledge 
base, and objectives--all without alteration. Retraining will result in 
new behaviors only as needed to address new scenarios that the model 
did not confront previously, and even then, only in a manner designed 
to further optimize outcomes, i.e., reduce mark-outs or increase fill 
rates. If the System assesses that a retrained model would be worse 
than the existing model in achieving its objectives, then the System 
will continue to use the existing model and discard the retrained 
model. This retraining process is a standard and accepted practice for 
use of deep learning models; it helps to ensure that deep learning 
models not only work well, but that they continue to work well in 
dynamic circumstances.\26\
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    \26\ During periods where the model is not undergoing 
retraining, the System will behave predictably from day to day, such 
that its decisions when presented with given set of facts and 
circumstances in a given security on day 1 should be the same as 
they would be on day 2.
---------------------------------------------------------------------------

    The Exchange will not modify the underlying structure of Dynamic M-
ELO and M-ELO+CB without first obtaining the Commission's approval to 
do so, including modifications to the data elements the model considers 
in making decisions about Holding Period durations, the conditions 
under which the model may adjust the duration of Holding Periods, the 
frequency with which the model my adjust the Holding Periods, the range 
of Holding Period durations available to M-ELOs and M-ELO+CBs, the 
increments by which Holding Periods may change at any given Change 
Event, and the procedures for triggering, maintaining, and ending 12 
millisecond Holding Periods during times of extraordinary 
instability.\27\

[[Page 22503]]

Although the Exchange will seek Commission approval prior to changing 
any of the data elements that the model considers, the Exchange will 
not seek Commission approval prior to retraining the model to adjust 
the weighting it applies to those data elements.
---------------------------------------------------------------------------

    \27\ In addition to the proposed changes described above, the 
Exchange proposes to delete an extraneous reference in Rule 
4702(b)(15) to M-ELO+CB being eligible to execute against a Midpoint 
Order on the Continuous Book if the Continuous Book order has the 
``Midpoint'' Trade Now Attribute enabled. In a prior filing, the 
Exchange folded the concept of ``Midpoint Trade Now'' into the 
general ``Trade Now'' Attribute. See Securities Exchange Act Release 
No. 34-92180 (June 15, 2021), 86 FR 33420 (June 24, 2021)(SR-NASDAQ-
2021-044).
---------------------------------------------------------------------------

    To aid investors in understanding and evaluating Dynamic M-ELO, 
Nasdaq will continue to publish weekly and monthly transparency 
statistics on Nasdaqtrader.com, as it does now, about the performance 
of its M-ELOs and M-ELO+CBs, including statistics listing the weekly 
numbers of shares and trades in M-ELOs by symbol, weekly aggregated M-
ELO share and trade data, and monthly aggregated block data.\28\ Nasdaq 
also will continue to disclose monthly data on Nasdaq.com, as it does 
now (the M-ELO Monthly Report), about M-ELO and M-ELO+CB mark-outs 
(quote stability by time horizon) and fill rates.\29\ Moreover, Nasdaq 
will add statistics to the M-ELO Monthly Report about how frequently, 
on average, the System changes Holding Period durations for the top 
decile, median, and bottom decile of symbols, as measured by monthly M-
ELO and M-ELO+CB trading volumes. Nasdaq will retain copies of each 
historical iteration of its models as part of its books and records, 
and make them available to the Commission upon request, should it wish 
to examine them to understand how the model changes over time. 
Furthermore, Nasdaq will publish an equity trader alert in advance of 
deploying a retrained version of Dynamic M-ELO whenever Nasdaq has 
reason to anticipate that the retrained version will produce results 
that differ materially from the prior version, i.e., a projected change 
in mark-outs or fill-rates of 10% or more in either direction.
---------------------------------------------------------------------------

    \28\ See http://www.nasdaqtrader.com/Trader.aspx?id=MELOSymbolData.
    \29\ See, e.g., https://www.nasdaq.com/docs/M-ELO-Monthly-Report. Nasdaq understands that current users of M-ELO and M-ELO 
independently monitor the performance of these Order Types. Nasdaq 
often receives feedback from such users about M-ELO and M-ELO+CB 
performance, which Nasdaq then factors into decisions about 
improvements and enhancements. Nasdaq expects that this feedback 
loop will continue after implementation of Dynamic M-ELO.
---------------------------------------------------------------------------

Implementation
    The Exchange intends to make the proposed change effective for M-
ELOs and M-ELO+CBs in the Second or Third Quarter of 2023, but that 
time frame is subject to change. The Exchange will publish a Trader 
Alert in advance of making the proposed change effective.
2. Statutory Basis
    The Exchange believes that its proposal is consistent with Section 
6(b) of the Act,\30\ in general, and furthers the objectives of Section 
6(b)(5) of the Act,\31\ in particular, in that it is designed to 
promote just and equitable principles of trade, 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, by allowing for more widespread use of M-ELOs and M-ELO+CBs.
---------------------------------------------------------------------------

    \30\ 15 U.S.C. 78f(b).
    \31\ 15 U.S.C. 78f(b)(5).
---------------------------------------------------------------------------

    When the Commission approved the M-ELO and the M-ELO+CB, it 
determined that these Order Types are consistent with the Act because 
they ``could create additional and more efficient trading opportunities 
on the Exchange for investors with longer investment time horizons, 
including institutional investors, and could provide these investors 
with an ability to limit the information leakage and the market impact 
that could result from their orders.'' \32\ Nothing about the 
Exchange's proposal should cause the Commission to revisit or rethink 
this determination. Indeed, the proposal will not alter the fundamental 
design of these Order Types, the manner in which they operate, or their 
effects.
---------------------------------------------------------------------------

    \32\ M-ELO Approval Order, supra 83 FR at 10938-39; M-ELO+CB 
Approval Order, supra, 84 FR at 48980.
---------------------------------------------------------------------------

    Even with Dynamic M-ELO Holding Periods, M-ELOs and M-ELO+CBs will 
continue to provide their users with protection against information 
leakage and adverse selection--and they will do so at levels which are 
substantially undiminished from that which they provide now.\33\
---------------------------------------------------------------------------

    \33\ See note 12, supra.
---------------------------------------------------------------------------

    At the same time, however, the proposal will benefit market 
participants and investors by reducing the opportunity costs of 
utilizing M-ELOs and M-ELO+CBs. The proposal, in other words, will re-
calibrate the lengths of the Holding Periods so that M-ELOs and M-
ELO+CBs will operate in the ``Goldilocks'' zone--their Holding Periods 
will not be so short as to render them unable to provide meaningful 
protections against information leakage and adverse selection, but the 
Holding Periods also will not be too long so as to cause participants 
and investors to miss out on favorable execution opportunities. Nasdaq 
believes the proposal will render M-ELOs and M-ELO+CBs more useful and 
attractive to market participants and investors, and this increased 
utility and attractiveness, in turn, will spur an increase in M-ELO and 
M-ELO+CB use cases on the Exchange, both from new and existing users of 
M-ELOs and M-ELO+CBs. Ultimately, the proposal should enhance market 
quality by increasing opportunities for midpoint executions on the 
Exchange.
    As Nasdaq explained above, the proposal will operate within strict, 
well-defined, and transparent parameters. Although it will undergo 
weekly retraining (outside of market hours), such retraining will aim 
to improve the performance of the model in achieving its twin 
objectives; retraining will not alter the inputs, objectives, or basic 
design parameters of Dynamic M-ELO without prior Commission 
approval.\34\ Moreover, the Exchange will not deploy a retrained model 
if it fails to achieve performance improvements. To aid investors in 
evaluating Dynamic M-ELO, the Exchange will publish statistics about 
its performance, including as to mark-outs and fill rates, as well as 
statistics about how frequently the System changes Holding Period 
durations. To further facilitate accountability, the Exchange will 
retain each historical iteration of its model as part of its books and 
records, and make such information available to the Commission, upon 
request. The Exchange will also publish equity trader alerts whenever 
retraining will result in a performance change of 10% or more.
---------------------------------------------------------------------------

    \34\ As discussed above, Nasdaq will not seek Commission 
approval prior to allowing the model, as part of its re-training 
process, to vary the weighting of the data elements it ingests. 
Nasdaq believes this is appropriate because such variance will only 
occur to the extent that it will improve the model's performance 
with respect to pre-defined objectives. Nasdaq will alert traders if 
the retraining process would result in substantial performance 
changes, and it will also publish statistics to help participants to 
assess performance themselves. Moreover, Nasdaq will retain 
historical iterations of its models for the Commission's review, 
should it wish to examine how these models have changed over time.
---------------------------------------------------------------------------

    Nasdaq notes that the twin objectives it prescribes for the model 
involve the absolute values of mark-outs and fill rates; they are not 
designed to further the performance of any participant or any category 
of participant. Thus, Nasdaq believes the model is objective and 
designed to avoid bias and discrimination.
    The Exchange notes that use of Dynamic M-ELOs and M-ELO+CBs remains 
voluntary for all market participants. Accordingly, if any market 
participant feels that the dynamic Holding Periods are still too long 
or too short or because competing venues offer more attractive delay 
mechanisms, then

[[Page 22504]]

the participants are free to pursue other trading strategies or utilize 
other trading venues. They need not utilize Dynamic M-ELOs or M-
ELO+CBs.
    Furthermore, the design of Dynamic-MELO would constitute an 
``established, non-discretionary'' method that is consistent with the 
definition of an exchange, as set forth in SEC Rule 3b-16.\35\ The 
Commission stated as follows when it adopted Rule 3b-16:
---------------------------------------------------------------------------

    \35\ See 17 CFR 240.3b-16(a)(2) (``(a) An organization, 
association, or group of persons shall be considered to constitute, 
maintain, or provide `a market place or facilities for bringing 
together purchasers and sellers of securities or for otherwise 
performing with respect to securities the functions commonly 
performed by a stock exchange,' as those terms are used in section 
3(a)(1) of the Act, (15 U.S.C. 78c(a)(1)), if such organization, 
association, or group of persons: (1) Brings together the orders for 
securities of multiple buyers and sellers; and (2) Uses established, 
non-discretionary methods (whether by providing a trading facility 
or by setting rules) under which such orders interact with each 
other, and the buyers and sellers entering such orders agree to the 
terms of a trade.'').

    A system uses established non-discretionary methods either by 
providing a trading facility or by setting rules governing trading 
among subscribers. The Commission intends for ``established, non-
discretionary methods'' to include any methods that dictate the 
terms of trading among the multiple buyers and sellers entering 
orders into the system. Such methods include those that set 
procedures or priorities under which open terms of a trade may be 
determined. For example, traditional exchanges' rules of priority, 
parity, and precedence are ``established non-discretionary 
methods,'' as are the trading algorithms of electronic systems. 
Similarly, systems that determine the trading price at some 
designated future date on the basis of pre-established criteria 
(such as the weighted average trading price for the security on the 
specified date in a specified market or markets) are using 
established, non-discretionary methods.\36\
---------------------------------------------------------------------------

    \36\ See Securities Exchange Act Release No. 40760 (December 8, 
1998), 63 FR 70844, 70850 (December 22, 1998).

    Nothing in the Reg. ATS Adopting Release or in any of its 
illustrative examples suggests that Dynamic M-ELO would constitute an 
exercise of discretionary behavior. Dynamic M-ELO will handle and 
execute Orders according to published, pre-determined rules that are 
disclosed to the public and which provide reasonable notice of how the 
Order Type will behave.\37\ To the extent that the design of the System 
permits variation in the Holding Periods for such Orders, it does so by 
design. The range of potential variations, the objectives that such 
variations are intended to achieve, and the factors that determine when 
such variations may occur are also predetermined and set forth in the 
Exchange's Rules or otherwise disclosed to the public. The mere fact 
that the System may apply different weights over time to the factors it 
uses to determine whether and by how much to vary a Holding Period does 
not mean that the System will act with discretion in the same sense 
that a human being could be said to be exercise independent judgment 
when deciding whether and how to handle an order.\38\ Even when the 
System makes decisions about changing the Holding Periods, the System 
will operate pursuant to a mathematical algorithm from which it cannot 
deviate--an algorithm that is programmed to achieve pre-defined and 
pre-disclosed objectives.\39\
---------------------------------------------------------------------------

    \37\ See id. at 70900 (``an essential indication of the non-
discretionary status of rules and procedures is that those rules and 
procedures are communicated to the systems users'' and ``[t]hus, 
participants have an expectation regarding the manner of execution--
that is, if an order is entered, it will be executed in accordance 
with those procedures and not at the discretion of a counterparty or 
intermediary.'').
    \38\ Cf. id. at 70851 (explaining that a traditional block 
trading desk is an example of a system that does not use 
established, non-discretionary methods because the operators of such 
desks do not act according to fixed procedures known to their 
customers, but instead shop orders around for potential 
counterparties and make their own determinations as to whether and 
how to execute block orders, including by sometimes deciding to take 
a proprietary position in part of the block order).
    \39\ See id. at 80755 (describing an example of a system that 
would be non-discretionary in nature: ``System I permits 
participants to enter a range of ranked contingent buy and sell 
orders at which they are willing to trade securities. These orders 
are matched based on a mathematical algorithm whose priorities are 
designed to achieve the participants' objectives. System I does not 
display orders to any participants. System I is included under Rule 
3b-16.''); see also Securities Exchange Act Release No. 34-89686 
(August 20, 2020), 85 FR 54438, at 54445, n.92 (September 1, 2020) 
(Order approving SR-IEX-2019-15) (rejecting argument that IEX's D-
Limit order time is an exercise of discretion because ``D-Limit 
orders will not allow IEX to exercise any discretion on any 
particular order by deviating from the CQI and D-Limit 
functionality, which is hardcoded in the IEX rulebook.''; Securities 
Exchange Act Release No. 34-78101 (June 17, 2016), 81 FR 41141, at 
41153(June 17, 2016) (Order approving IEX Form 1 and D-Peg Order 
Type) (``the Commission does not believe that the hardcoded 
conditionality of the IEX proposed ``discretionary'' peg order type 
provides IEX with actual discretion or the ability to exercise 
individualized judgment when executing an order. Rather, if IEX's 
fixed formula determines the quote to be stable, the discretionary 
peg order can execute up to the midpoint; if it does not deem the 
quote to be stable, then it will hold the order to its pegged price. 
As such, IEX would not exercise discretion over the routing and 
execution of a resting order''). Nasdaq does not believe that it is 
necessary to codify its mathematical formula for Dynamic M-ELO in 
its Rules because Nasdaq has disclosed sufficient information in its 
Rules and in its filing to inform the public as to the possible and 
expected behaviors associated with Dynamic M-ELO, as well as a means 
for the Commission and/or investors to verify whether Dynamic M-ELO 
is performing appropriately. Much as the Commission does not require 
an exchange to codify the source code it uses to effectuate other 
behaviors or actions that it explains in its Rules, including the 
behaviors of other complex Order Types, there is no basis to require 
codification of the Dynamic M-ELO formula in this instance.
---------------------------------------------------------------------------

    Finally, the Exchange notes that it will continue to conduct real-
time surveillance to monitor the use of M-ELOs and M-ELO+CBs to ensure 
that such usage remains appropriately tied to the intent of the Order 
Types. If, as a result of such surveillance, the Exchange determines 
that the Dynamic M-ELO Holding Periods do not serve their intended 
purposes, or adversely impact market quality, then the Exchange will 
seek to make further re-calibrations.

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

    The Exchange does not believe that the proposed rule change will 
impose any burden on competition not necessary or appropriate in 
furtherance of the purposes of the Act. To the contrary, the Exchange 
believes that this proposal will promote the competitiveness of the 
Exchange by rendering its M-ELO and M-ELO+CB Order Types more 
attractive to participants.
    The Exchange adopted the M-ELO and M-ELO+CB as pro-competitive 
measures intended to increase participation on the Exchange by allowing 
certain market participants that may currently be underserved on 
regulated exchanges to compete based on elements other than speed. The 
proposed change continues to achieve this purpose. With Dynamic M-ELO 
Holding Periods, both M-ELOs and M-ELO+CBs will afford their users with 
a level of protection from information leakage and adverse selection 
that is better from what is achievable at present.\40\ At the same 
time, the Dynamic Holding Periods will increase opportunities to 
interact with other like-minded investors with longer time horizons 
while also lowering the opportunity costs for participants that utilize 
M-ELOs and M-ELO+CBs, particularly for securities that trade within the 
``Goldilocks'' zone. In sum, the proposed changes will not burden 
competition, but instead may promote competition for liquidity in M-
ELOs and M-ELO+CBs by broadening the circumstances in which market 
participants may find such Orders to be useful. With the proposed 
changes, market participants will be more likely to determine that the 
benefits of entering M-ELOs and M-ELO+CBs outweigh the risks of doing 
so.
---------------------------------------------------------------------------

    \40\ See White Paper, supra.
---------------------------------------------------------------------------

    The proposed change will not place a burden on competition among 
market

[[Page 22505]]

venues, as any market may adopt an order type that operates similarly 
to a M-ELO or a M-ELO+CB with Dynamic M-ELO Holding Periods.

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

    No written comments were either solicited or received.

III. Proceedings To Determine Whether To Approve or Disapprove SR-
NASDAQ-2022-079, as Modified by Amendment No. 1, and Grounds for 
Disapproval Under Consideration

    The Commission is instituting proceedings pursuant to Section 
19(b)(2)(B) of the Act \41\ to determine whether the proposed rule 
change, as modified by Amendment No.1, should be approved or 
disapproved. Institution of proceedings is appropriate at this time in 
view of the legal and policy issues raised by the proposed rule change 
and the comments received thereon. Institution of proceedings does not 
indicate that the Commission has reached any conclusions with respect 
to any of the issues involved. Rather, the Commission seeks and 
encourages interested persons to provide additional comment on the 
proposed rule change to inform the Commission's analysis of whether to 
approve or disapprove the proposed rule change.
---------------------------------------------------------------------------

    \41\ 15 U.S.C. 78s(b)(2)(B).
---------------------------------------------------------------------------

    Pursuant to Section 19(b)(2)(B) of the Act,\42\ the Commission is 
providing notice of the grounds for possible disapproval under 
consideration. As noted above, the Commission received two comments on 
the proposal and the Exchange simultaneously filed a response to 
comments along with Amendment No. 1.\43\ Of note, both commenters 
assert that the Exchange must provide additional information about how 
it determines the Dynamic Holding Periods proposed herein.\44\ One of 
these commenters states that ``as a threshold question, how can the 
public `provide meaningful comment on the proposal' without knowing 
what all the categories and parameters are.'' \45\ This commenter also 
states that it is unclear under what circumstances the Exchange 
believes it would need to file a proposed rule change should the 
machine learning model alter its methods or functionalities, 
specifically citing the proposed retraining of the artificial 
intelligence based timer control system.\46\ This commenter also 
questions whether the proposed rule change provides sufficient 
information to determine whether (i) it is not unfairly discriminatory 
and (ii) will not place a burden on competition among market 
venues.\47\
---------------------------------------------------------------------------

    \42\ Id.
    \43\ See supra note 6.
    \44\ See Letters from Joseph Saluzzi, Partner, Themis Trading 
LLC, to Vanessa Countryman, Secretary, Commission, dated January 25, 
2023, at 2 (``Nasdaq should be required to reveal all of the 
specifics behind their dynamic holding period formula so others can 
evaluate how it works and decide if they would like to have Nasdaq 
apply the logic to their orders.''); and R. T. Leuchtkafer to 
Vanessa Countryman, Secretary, Commission, dated January 31, 2023, 
at 1-2 (``Leuchtkafer Letter'').
    \45\ See Leuchtkafter Letter, at 1.
    \46\ See id., at 2 (stating that ``it's not at all clear under 
exactly what circumstances Nasdaq will seek approval for a 
change.'').
    \47\ See id., at 2-3.
---------------------------------------------------------------------------

    Nasdaq replied to these comments with its own comment letter and by 
filing Amendment No. 1. Nasdaq states, among other things, that it is 
not necessary to describe precisely how its system will react in each 
and every circumstance it will confront in the market as long as the 
choices that the system can make are bounded and its range of behaviors 
are understood and reasonably predictable, which it asserts is ``indeed 
the case for Dynamic M-ELO.'' \48\ Nasdaq also submitted the full list 
of these data elements as both an Appendix A to its response to 
comments and new Exhibit 3B to the proposal in Amendment No. 1. Nasdaq 
also states that:
---------------------------------------------------------------------------

    \48\ See Letter from Brett Kitt, Associate Vice President and 
Principal Associate General Counsel, Nasdaq, Inc., to Vanessa 
Countryman, Secretary, Commission, dated March 9, 2023, at 2 
(``Nasdaq Letter'').

    Nasdaq is clear that it will seek approval prior to altering the 
data inputs that the system ingests for decision-making purposes, 
but not for changes to the relative weighting that the system 
applies to these data elements. Nasdaq also will seek Commission 
approval prior to altering the twin objectives of Dynamic M-ELO or 
making changes to its fundamental operating parameters, such as 
changes to the permissible range of Holding Periods, to the 
permissible change increments for a Holding Period at any given 
Change Event, to the frequency with which Change Events may occur, 
to the procedures for triggering, maintaining, and ending 12 
millisecond Holding Periods during times of extraordinary 
instability.\49\
---------------------------------------------------------------------------

    \49\ See Nasdaq Letter at 3.

    The Commission is instituting proceedings to allow for additional 
analysis of, and input from commenters with respect to, the consistency 
of the proposal, as modified by Amendment No. 1, with Sections 6(b)(5) 
\50\ and 6(b)(8) of the Act.\51\ Section 6(b)(5) of the Act requires 
that the rules of a national securities exchange be designed, among 
other things, to promote just and equitable principles of trade, 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, and not be designed to permit unfair 
discrimination between customers, issuers, brokers, or dealers. Section 
6(b)(8) of the Act requires that the rules of a national securities 
exchange not impose any burden on competition that is not necessary or 
appropriate in furtherance of the purposes of the Act.
---------------------------------------------------------------------------

    \50\ 15 U.S.C. 78f(b)(5).
    \51\ 15 U.S.C. 78f(b)(8).
---------------------------------------------------------------------------

IV. Procedure: Request for Written Comments

    The Commission requests that interested persons provide written 
submissions of their views, data, and arguments with respect to the 
issues identified above, as well as any other concerns they may have 
with the proposal, as modified by Amendment No. 1. In particular, the 
Commission invites the written views of interested persons concerning 
whether the proposal, as modified by Amendment No. 1, is consistent 
with Sections 6(b)(5) and 6(b)(8), or any other provision of the Act, 
or the rules and regulations thereunder. Although there do not appear 
to be any issues relevant to approval or disapproval that would be 
facilitated by an oral presentation of views, data, and arguments, the 
Commission will consider, pursuant to Rule 19b-4, any request for an 
opportunity to make an oral presentation.\52\
---------------------------------------------------------------------------

    \52\ Section 19(b)(2) of the Act, as amended by the Securities 
Act Amendments of 1975, Public Law 94-29 (June 4, 1975), grants the 
Commission flexibility to determine what type of proceeding--either 
oral or notice and opportunity for written comments--is appropriate 
for consideration of a particular proposal by a self-regulatory 
organization. See Securities Act Amendments of 1975, Senate Comm. on 
Banking, Housing & Urban Affairs, S. Rep. No. 75, 94th Cong., 1st 
Sess. 30 (1975).
---------------------------------------------------------------------------

    Interested persons are invited to submit written data, views, and 
arguments regarding whether the proposal, as modified by Amendment No. 
1, should be approved or disapproved by May 4, 2023. Any person who 
wishes to file a rebuttal to any other person's submission must file 
that rebuttal by May 18, 2023.
    Comments may be submitted by any of the following methods:

Electronic Comments

     Use the Commission's internet comment form (https://www.sec.gov/rules/sro.shtml); or

[[Page 22506]]

     Send an email to [email protected]. Please include 
File Number SR-NASDAQ-2022-079 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 Numbers SR-NASDAQ-2022-079. 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 submission, all subsequent amendments, all 
written statements with respect to the proposed rule change that are 
filed with the Commission, and all written communications relating to 
the proposed rule change between the Commission and any person, other 
than those that may be withheld from the public in accordance with the 
provisions of 5 U.S.C. 552, will be available for website viewing and 
printing in the Commission's Public Reference Room, 100 F Street NE, 
Washington, DC 20549, on official business days between the hours of 
10:00 a.m. and 3:00 p.m. Copies of these filings also will be available 
for inspection and copying at the principal office of the Exchange.
    All comments received will be posted without change. Persons 
submitting comments are cautioned that we do not redact or edit 
personal identifying information from comment submissions. You should 
submit only information that you wish to make available publicly. All 
submissions should refer to File Number SR-NASDAQ-2022-079 and should 
be submitted on or before May 4, 2023. Rebuttal comments should be 
submitted by May 18, 2023.

    For the Commission, by the Division of Trading and Markets, 
pursuant to delegated authority.\53\
---------------------------------------------------------------------------

    \53\ 17 CFR 200.30-3(a)(12), (57).
---------------------------------------------------------------------------

Sherry R. Haywood,
Assistant Secretary.
[FR Doc. 2023-07733 Filed 4-12-23; 8:45 am]
BILLING CODE 8011-01-P


