FINRA Rule 6121.02 governs trading in FINRA-covered securities during and after a market-wide circuit breaker halt. FINRA has amended the rule so that trading resumes at 4:00 a.m. Eastern Time or later on the next trading day following a Level 3 halt, rather than at the start of the regular session. The amendment takes effect December 6, 2026.

A Level 3 halt is the terminal one. When the S&P 500 declines 20% from its prior close, trading halts market-wide for the remainder of the day. There is no intraday resumption. The only question the rule answers is when the market opens again, and that answer has consequences for firms whose sessions now start long before 9:30 a.m.

What Rule 6121.02 does, and what changed

Rule 6121.02 addresses trading in FINRA-covered securities during a market-wide circuit breaker event declared by the primary listing markets. It sets out how FINRA members halt and resume trading, and it links FINRA's treatment to the halt declarations published under the market-wide circuit breaker plan.

The amended rule retains a resumption time of 4:00 a.m. Eastern Time or later on the next trading day following a Level 3 halt. Read plainly, the rule does not require the market to reopen at exactly 4:00 a.m. It establishes a floor. Trading in FINRA-covered securities does not resume before 4:00 a.m. ET on that next trading day, and the actual reopening follows the operating schedule of the venues involved.

That distinction is not pedantry. A firm reading "4:00 a.m." as a guaranteed opening time will build an order-handling process around an event that may not occur at that moment. A firm reading it as a prohibition on earlier resumption will build a process that waits for the actual opening and handles the interval correctly.

Why the resumption time is a substantive question

Twenty years ago, the gap between a Level 3 halt and the next open was uneventful because nothing traded in between. That gap has closed. Overnight sessions, extended-hours execution, and 23/5 operating schedules mean that for a substantial set of firms, the "next trading day" begins at 4:00 a.m. or earlier, not at 9:30 a.m.

Three things happen in that window, and all three are compliance-relevant:

• Orders arrive. Clients and algorithms submit instructions for the reopen, often conditioned on the halt lifting. Whether those orders are accepted, held, or rejected is a policy decision that must be documented before it is tested under pressure.
• Prices are established. The first prints after a 20% decline set the reference point for a large volume of activity, including risk limits, margin calls, and client notifications.
• Reporting begins. Trade reporting obligations attach to executions, and the operating hours of the reporting facility determine when reports are due. That is why the December 6 date also carries trade reporting changes.

Who is affected

The amendment applies to FINRA members trading FINRA-covered securities, but the practical impact is uneven. Firms with the greatest exposure to operational error are those with overnight or pre-market activity.

• Firms operating 23/5 or overnight sessions. The handoff between overnight and pre-market staff, systems, and risk limits now has a defined regulatory anchor.
• Firms routing or executing in extended hours. Order acceptance rules for the reopen, and the treatment of orders queued during the halt, need to be written down.
• Firms with retail client communication obligations. Clients will ask what happened and when they can trade. A prepared, accurate answer is a supervisory control, not a courtesy.
• Order handling and OATS/CAT reporting functions. Reporting timelines and sequencing after a halt depend on the operating hours of the relevant facility.
• Clearing and margin operations. A 20% decline produces margin calls and risk limit breaches that arrive on the same schedule as the reopen.

Compliance considerations

The following are suggested practices for review. They are not additional requirements created by the amendment.

1. Confirm every reference to the resumption time in your procedures. Search written supervisory procedures, order handling documentation, client agreements, and system configuration notes for any statement that trading resumes at the start of the regular session after a Level 3 halt. The amendment makes that statement wrong.
2. Define the handling of orders submitted during the halt. Decide, in writing, whether orders are accepted and held, rejected, or accepted with a condition. Then confirm the systems do what the document says.
3. Review good-till-cancelled and day-order treatment. A halt that ends a trading day affects the life of a day order and the persistence of a GTC order. The answer should be explicit rather than emergent.
4. Rehearse the restart. A tabletop exercise that walks an overnight desk through a 20% decline, the halt, and the 4:00 a.m. reopen will surface more gaps than a document review, particularly around who has authority to act.
5. Align client communications. Prepare a holding statement for client-facing staff that states the resumption rule accurately, distinguishes the floor from a guaranteed opening time, and avoids predicting the market.
6. Check the trade reporting operating hours. The resumption change lands on the same date as trade reporting facility operating hour changes, so treat them as one implementation rather than two.
7. Update training. Overnight and pre-market staff are the audience that matters most. A firm that trains only the day desk has trained the people least likely to be present when the rule operates.

Important dates

FINRA has not, at the time of writing, published a notice describing a grace period for the amendment. Firms should plan to be compliant on the effective date rather than assume supervisory forbearance.

Conclusion

The amendment is narrow and the operational surface is not. A rule that fixes a resumption time touches order handling, reporting, client communication, and staffing, because the market it governs now operates around the clock. Firms that treat December 6 as a date to update one sentence in a procedures manual will find the sentence was load-bearing.

The best preparation is unglamorous. Read the rule as a prohibition rather than a schedule. Write down what happens to an order submitted during a halt. Rehearse the restart with the people who will actually be on shift at 4:00 a.m. Then confirm that the systems agree with the document, which is the step most firms skip.

Soflo Consulting supports financial services organizations with AML/BSA program development, risk assessment, and compliance training. Circuit breaker mechanics are a securities operations and supervision matter rather than a financial crime one, and where a review of a halt scenario raises an AML question we will say so rather than stretch the analysis. Our work on monitoring design addresses how control testing is structured, which applies to operational rehearsals as well. To discuss a review, contact Soflo Consulting.

Disclaimer: This article is provided for general informational and educational purposes only and does not constitute legal advice. Rule 6121.02 and the amendment described reflect publicly available information as of November 11, 2026, and firms should verify all details against FINRA's published rule text and notices before relying on them. Market-wide circuit breaker thresholds and halt mechanics are set by the primary listing markets. Soflo Consulting is not affiliated with, endorsed by, or approved by FINRA or the SEC.