FINRA has opened a consultation on the guidance beneath Rule 5310 because the SEC intends to delete Rule 611 of Regulation NMS — but the two rules do not bind the same firms, and FINRA concedes that the benchmark members use to demonstrate best execution is itself a by-product of the rule being repealed.

The Financial Industry Regulatory Authority (FINRA) published Regulatory Notice 26-15 on July 24, 2026, opening a comment period that closes on September 25, 2026. The trigger is stated on page one: as part of the FINRA Forward modernization initiative, “and in light of significant market structure developments—including the SEC’s proposal to rescind the trade-through rule under Regulation NMS—FINRA is reviewing its best execution guidance to ensure that Rule 5310 remains durable and effective in an evolving marketplace.” That proposal is Securities Exchange Act Release No. 105655, 91 FR 36656, of June 17, 2026. What follows examines who each rule binds, why the residual duty is measured against a yardstick the repeal unsettles, and what belongs in a comment letter.

Key facts

• Instrument: FINRA Regulatory Notice 26-15, issued July 24, 2026. Comment period expires September 25, 2026.
• Under review: the interpretive guidance beneath FINRA Rule 5310, not the rule text. FINRA “preliminarily believes that the best execution rule text in Rule 5310 and its supplementary material remains appropriately calibrated” (section D).
• Trigger: proposed rescission of 17 CFR 242.611 and 242.610(e), with conforming deletion of defined terms in Rule 600(b).
• Age of the duty: Rule 5310 and its predecessors have bound FINRA members since 1968 — 37 years before Regulation NMS (section A).
• Venue count: 17 national securities exchanges now trade NMS stocks, three more are approved, against eight in 2005; off-exchange trading has “since the end of 2024, now regularly exceed[ed] 50% of overall volume” (Release No. 105655, at 36658).
• FINRA’s own venue is dormant: its Alternative Display Facility, the one national securities association quotation facility Rule 611 protects, “currently has no active quoting participants” (endnote 24).

The documents this rests on

Four primary sources were read in full: FINRA Regulatory Notice 26-15 and its 53 endnotes; the SEC rescission proposal at 91 FR 36656–36735; Chairman Paul S. Atkins’ Remarks at the Roundtable on Trade-Through Prohibitions of September 18, 2025; and the Dissent of Commissioners Cynthia A. Glassman and Paul S. Atkins to Regulation NMS, at 70 FR 37639–43. Enforcement detail is drawn from FINRA BrokerCheck firm records; the comparative table is sourced to the primary texts of Directive 2014/65/EU, the FCA Handbook and National Instrument 23-101 rather than to secondary summaries. Every quotation is taken from document text with a section or page reference. The scope is narrow: this is an analysis of legal addressees, not a forecast of execution quality, and neither US instrument is final law as at September 3, 2026.

Rule 611 binds trading centers; Rule 5310 binds members handling customer orders

The SEC’s central justification for deleting structural price protection is that nothing of substance is lost, because an older duty already covers the ground. Rule 611, the Commission wrote, “is not needed as a backstop to best execution given today’s highly automated, interconnected and competitive equity markets, where retail investors have widely available access to market data and execution quality information, and a broker’s duty to provide best execution would apply regardless” (Release No. 105655, at 36664; quoted at FINRA endnote 7). That reasoning holds only if the backstop reaches the same firms as the thing it backstops.

Rule 611 binds “trading centers” — defined at 17 CFR 242.600(b)(106) to capture national securities exchanges, alternative trading systems (ATSs), over-the-counter market makers, and any other broker-dealer that executes orders internally. The obligation attaches to the venue as a venue, whoever the counterparty may be. FINRA Rule 5310(a)(1) is addressed quite differently. It applies “[i]n any transaction for or with a customer or a customer of another broker-dealer,” and FINRA Rule 0160(b)(4) provides that “customer” does not include a broker-dealer. The duty runs from a member to a customer, and where there is no customer it does not exist.

The resulting gap has two shapes, and neither is closed by the residual duty. A national securities exchange is not a FINRA member and has no customers in the Rule 5310 sense, so after rescission it would carry no best execution duty at all — because it never carried one, and nothing in Notice 26-15 proposes to give it one. An ATS operator is a member, but its subscribers are ordinarily broker-dealers, whom Rule 0160(b)(4) expressly excludes. Only the third category, the broker-dealer internalising a retail order, sits inside both rules at once, and that firm is already the most closely supervised: Supplementary Material .09 to Rule 5310 requires an order-by-order analysis of execution quality for internalised flow, against a security-by-security, type-of-order review conducted at least quarterly for everything else. The residual duty is real, but it is narrower than the structure it is being asked to replace.

FINRA’s own venue-side hook makes the point vivid. Rule 611 protects quotations displayed on a national securities association as well as on an exchange, and FINRA is the only registered association, operating the Alternative Display Facility — which, endnote 24 records, “currently has no active quoting participants.” The single place where FINRA’s jurisdiction and the trade-through rule’s addressee coincide is empty.

Four markets, two answers about who carries the duty

The United States is unusual in having run a venue-level price-protection rule and an intermediary-level best execution duty side by side for two decades. Most comparable markets chose one.

Jurisdiction / regulator	Venue-level order protection	Intermediary best execution duty	Who is bound	Recent change or sanction
US (SEC + FINRA)	Rule 611, 17 CFR 242.611, in force since 2005	FINRA Rule 5310, since 1968; not proposed for amendment	Rule 611: trading centers (17 CFR 242.600(b)(106)). Rule 5310: FINRA members, customer orders only — Rule 0160(b)(4) excludes broker-dealers	Rescission of Rules 611 and 610(e) proposed at 91 FR 36656 (June 17, 2026)
EU (national competent authorities under MiFID II)	None — MiFID II contains no order-protection provision	Article 27, Directive 2014/65/EU: firms must “take all sufficient steps to obtain… the best possible result for their clients,” applicable from January 3, 2018 under Article 93(1) as amended by Directive (EU) 2016/1034	Investment firms only; trading venues are not addressees of Article 27	Venue execution-quality reporting under Article 27(3) and (6) deleted by Directive (EU) 2024/790, Article 1(4), transposition due September 29, 2025. Fines: “at least EUR 5 000 000 or up to 10 % of total annual turnover” (Article 70(6)(f))
UK (FCA)	None; the share trading obligation in UK MiFIR Article 23 was removed by the Financial Services and Markets Act 2023, Schedule 2, paragraph 13	COBS 11.2A.2R: “A firm must take all sufficient steps to obtain… the best possible results for its clients,” effective January 3, 2018	“A firm” — the authorised intermediary	RTS 27 and RTS 28 reports removed from December 1, 2021 (Conduct of Business Sourcebook (Amendment) Instrument 2021, FCA 2021/59)
Canada (CSA)	Order Protection Rule, National Instrument 23-101 section 6.1 — a marketplace “must establish, maintain and ensure compliance with written policies and procedures reasonably designed… to prevent trade-throughs”; dealer-side duty at section 6.4	NI 23-101 section 4.2: “A dealer and an adviser must make reasonable efforts to achieve best execution when acting for a client”	Marketplaces (s.6.1) and marketplace participants (s.6.4); dealers and advisers (s.4.2)	Protection narrowed to marketplaces meeting a 2.5% market-share threshold, in force October 1, 2016

Sources: 17 CFR 242.611 and 242.600(b)(106); FINRA Rules 5310 and 0160(b)(4); SEC Release No. 105655; Directives 2014/65/EU, (EU) 2016/1034 and (EU) 2024/790; FCA Handbook COBS 11.2A; NI 23-101 and the CSA Notice of Approval of April 7, 2016. Last updated September 3, 2026.

The comparison isolates the peculiarity of the American arrangement, and shows the direction of travel elsewhere. In the EU and the UK the duty has only ever attached to the intermediary, so there is no structural protection to remove and no addressee gap to open — and both have gone further, stripping out the venue-level execution-quality reports that once let firms compare markets on published data. Canada is the closer analogue, having adopted an order protection rule and then, rather than deleting it, narrowed protection to marketplaces above a 2.5% market-share threshold from October 1, 2016. That is the middle path the SEC examined and rejected: the proposal considers “a minimum volume threshold requirement for an automated trading center to qualify for having a protected quote,” under which sub-threshold quotes “would continue to be disseminated via the SIP and could contribute to the NBBO for transparency and benchmarking purposes, but they would not be protected” (section VI.E.1). The Commission judged both the benefits and the costs of that alternative lower than outright rescission — a defensible call, and the one option that would have left the addressee structure intact. Our survey of how best execution splits EU, UK and US rules traces the same divergence in foreign exchange.

“In our dissent, we argued that it would have been better ‘to improve access to quotations, enhance connectivity among markets and market participants, clarify the broker’s duty of best execution, and reduce barriers to competition.'”

— Paul S. Atkins, Chairman, US Securities and Exchange Commission, Remarks at the Roundtable on Trade-Through Prohibitions, September 18, 2025 (SEC.gov)

Proving best execution against a yardstick the repeal unsettles

FINRA does not dispute that the two rules are legally distinct: “the reasonable diligence standard and related interpretive guidance under Rule 5310 apply regardless of the existence of a trade-through rule” (section C). What it then concedes is operational, and more interesting. FINRA “recognizes that the national best bid and offer (NBBO) is used by firms as a key benchmark for evaluating order routing and internalization decisions,” and adds that “firms may be required to connect and route to venues that display protected quotes for purposes of compliance with Rule 611, regardless of any independent analysis of such venues’ execution quality for best execution purposes.”

Those two sentences describe a compliance architecture built on top of Rule 611 though never legally dependent on it. The NBBO does not vanish on rescission — the Securities Information Processors would keep publishing it, as FINRA notes at question 1(d). What vanishes is its protected status, and with it the guarantee that the quotations feeding it are immediately and automatically accessible in the round-lot sizes that made price improvement measurable. FINRA’s questions follow directly: will the NBBO “remain an important benchmark from which to measure price improvement for best execution purposes, including when internalizing orders,” and if not, what replaces it — time-weighted or volume-weighted average prices, or a principle for choosing among them? The notice points to markets where firms already work without a consolidated quote: OTC equity securities, and NMS stocks overnight when the SIPs are dark. If the answer is “whatever firms already do over the counter,” a principles-based standard is being asked to carry work a bright-line rule used to do, with the evidentiary burden moving onto the member.

Twenty-one years of a contested rule, and the Commissioner who dissented

Rule 611 has been argued over since the day it was adopted. The Commission approved Regulation NMS on June 9, 2005 (Release No. 51808, 70 FR 37496) and two of the five Commissioners dissented. One was Paul S. Atkins, who now chairs the Commission proposing the repeal. The joint dissent with Commissioner Cynthia A. Glassman reads oddly well against the present consultation: the dissenters wanted to “clarify the broker’s duty of best execution.” Twenty-one years on, that clarification is the item on FINRA’s desk.

The intervening data explains why the argument never settled. Eight exchanges traded NMS stocks in 2005; there are now 17 operating and three approved, and commenters cited in the proposal report that six of them account for roughly 80% of on-exchange volume while 10 individually hold less than 2% market share. A rule whose stated purpose, in Atkins’ words, was “to increase displayed depth and liquidity in the NMS and thereby reduce transaction costs” has coincided with displayed liquidity fragmenting across a venue population that has more than doubled. His September 2025 critique went to the mechanism FINRA is now consulting on: the rule, he said, “restricted the price at which investors could trade by mandating execution at or within the National Best Bid and Offer (NBBO). This led the industry to treat price as the only factor when considering ‘Best Execution.'” Whether removing the structure restores the multi-factor analysis Rule 5310 always required, or simply removes the floor beneath it, is what the comment file must answer.

Enforcement context: what a Rule 5310 case has actually looked like

Best execution is enforced, and it is enforced against members rather than venues — the addressee point restated in the language of penalties. In AWC No. 2014041809401, accepted December 22, 2023, Interactive Brokers LLC consented to a censure and a $3.5 million fine, with no restitution ordered, for conduct running “from at least January 2014 through February 2023.” The BrokerCheck record cites Rules 5310(a)(1) and 5310.09 for the review failures and Rule 5310(a)(2) for interpositioning — roughly 10.4 million customer transactions were routed through two broker-dealers engaged in net trading. Earlier, in AWC No. 2017056224001 of December 19, 2019, Robinhood Financial paid $1.25 million and accepted an independent-consultant undertaking after FINRA found that, because whole categories of orders were excluded from review, “hundreds of thousands of orders each month fell outside the firm’s regular and rigorous review process.” Barclays Capital paid $2 million on comparable grounds in October 2022.

Two features matter for the post-Rule 611 world. First, none of that conduct turned on a trade-through: the violations concerned the adequacy of the member’s own process — whether competing venues were examined, whether rebate economics distorted routing, whether supervision was reasonably designed. That machinery lives in Supplementary Material .09 and survives the repeal untouched. Second, and less comfortably, each case was built in a market where the NBBO supplied an uncontested reference price against which disimprovement could be shown. Remove the protected quotation and the regulator’s evidentiary task changes as much as the member’s — which is why FINRA asks at question 1(j) “what types of data should FINRA consider in overseeing compliance with Rule 5310.”

What a compliance function should do before September 25

For routing and introducing brokers, the immediate task is an inventory, not a redesign: identify every policy, procedure and system control citing Rule 611, a protected quotation, an intermarket sweep order, or a Rule 600(b) term slated for deletion, because those citations become dangling references on adoption. Question 1(k) asks exactly what procedures members should have “assuming rescission of Rules 610(e) and 611” — an invitation to describe the gap before it is legislated rather than after.

For internalising firms and wholesalers, the order-by-order review requirement is explicitly on the table. Any firm that wants it relaxed should be filing evidence now, and any firm using the NBBO as its price-improvement denominator should be documenting the alternative. For venue operators, including ATSs and single-dealer platforms, the notice asks whether an operator owes best execution to an institutional customer accessing it directly, beyond the directed-order treatment in Supplementary Material .08 — the addressee question arriving from the other direction, and the one place FINRA might extend rather than relax the duty.

For legal and compliance, three items belong in the September file: the proposed alternative benchmark and the data behind it; a position on whether a Rule 5310 safe harbour should exist and on what parameters, since FINRA asks at question 1(i); and a view on the “blanket” not-held provisions the notice treats with visible scepticism.

“While these factors may be appropriate for assessing smaller retail orders, each factor is not necessarily appropriate or effective in assessing the execution quality of larger institutional orders, in particular those handled via an algorithm.”

— Bernard V. Canepa, Managing Director and Associate General Counsel, SIFMA, letter to FINRA dated June 11, 2025, quoted at endnote 36 of Regulatory Notice 26-15

What FINRA has actually asked, and what happens after the deadline

Notice 26-15 is not a narrow consultation dressed as a broad one. It runs to nine topic areas and more than 50 discrete questions, from best execution after Rules 611 and 610(e), access fees, review standards and institutional orders through to extended trading hours, held and not held orders, listed options, and emerging technologies — where FINRA asks whether guidance specific to tokenised securities is needed and whether members use artificial intelligence in routing.

Three dependencies will shape the outcome. The SEC has not adopted its proposal, so FINRA’s questions are framed conditionally throughout. The Commission has separately signalled a review of the access fee caps: Atkins stated on June 11, 2026, in a passage FINRA reproduces at endnote 33, that he had “directed the staff to prioritize a review of Rules 610(c) and 612 of Regulation NMS by the end of the year” — a review that would move the economics of venue access fees and rebates that FINRA’s second topic asks about. And the SEC anticipates that most, if not all, self-regulatory organisations would seek to amend their locking and crossing rules, putting FINRA Rule 6240 and the exchange equivalents into a second wave. Comments close on September 25, 2026, and FINRA posts them as they are received.

Frequently asked questions

What is FINRA Regulatory Notice 26-15?

A request for comment, issued July 24, 2026, on modernising FINRA’s best execution guidance. FINRA says the text of Rule 5310 remains appropriately calibrated, so the consultation targets the interpretive guidance built on top of it, principally Regulatory Notice 15-46. Comments close September 25, 2026.

Does rescinding Rule 611 remove the duty of best execution?

No. Rule 5310 is a separate obligation dating to 1968 and is not proposed for amendment; FINRA states the reasonable diligence standard applies “regardless of the existence of a trade-through rule.” What changes is who is structurally constrained: Rule 611 binds trading centers including exchanges, Rule 5310 binds FINRA members handling customer orders.

Why does the difference in addressees matter?

Because the SEC’s justification is that best execution backstops the trade-through rule, and a backstop only works where it reaches the same firms. National securities exchanges are not FINRA members and have no customers under Rule 0160(b)(4), so no residual duty attaches to them. The overlap is limited to broker-dealers that internalise customer orders.

Will the NBBO still exist after rescission?

Yes. The Securities Information Processors would keep publishing the national best bid and offer, but quotations would no longer be protected. FINRA asks whether it remains an appropriate benchmark for measuring price improvement and what might serve instead, noting firms already operate without a consolidated quote in OTC equities and overnight.

Are order-by-order reviews of internalised flow going to change?

That is open. Supplementary Material .09 currently requires an order-by-order analysis for orders a firm executes from its own inventory, with a security-by-security, type-of-order review at least quarterly for other flow. FINRA asks whether the order-by-order requirement should continue and, if not, what would manage the conflict of interest instead.

What does the notice say about retail orders marked “not held”?

FINRA says it is concerned about categorising small retail orders as not held where the customer expects immediate and full execution at the best available price. It reports observing blanket provisions in new account agreements treating a customer’s orders that way, and is considering guidance.

This article is informational analysis only and does not constitute legal, regulatory, tax, or investment advice. Regulatory frameworks change frequently and interpretation depends on facts and circumstances; primary documents and official regulator guidance always supersede summaries. Firms should consult qualified legal counsel and their relevant supervisory authority before taking any action based on the analysis above.