2026-20604NoticeWallet

Nasdaq PHLX Preps Halt Resumes for 23-Hour Trading Era

Published Date: 10/8/2026

Notice

Summary

Nasdaq PHLX is updating its rules to handle trading restarts after a big market pause called a Level 3 circuit breaker. This change matches the new longer trading hours—23 hours a day, 5 days a week—so trading can resume smoothly and safely. Traders and investors will see these updates take effect right away, helping keep the market steady during extreme events.

Analyzed Economic Effects

2 provisions identified: 1 benefits, 0 costs, 1 mixed.

Level 3 Halt: Reopening Delayed Until 4:00 a.m. ET

If a Level 3 Market Decline (a 20% decline in the S&P 500 Index) occurs, trading on Nasdaq PHLX will remain halted until 4:00 a.m. Eastern Time or later on the following trading day. This preserves the current practice even after the industry expands to 23 hours per day, 5 days per week and even though some exchanges plan overnight sessions starting at 9:00 p.m. ET (targeted December 6, 2026).

Keeps Coordinated Market-Wide Cooling-Off Period

The Exchange amended Rule 3101 so that, under 23/5 Trading, all self-regulatory organizations will continue to follow a harmonized resumption practice after a Level 3 halt, reopening no earlier than 4:00 a.m. ET. The rule change codifies that no SRO would start an overnight trading session on the same calendar day as a Level 3 Market Decline, supporting coordinated price discovery and investor protection.

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Key Dates

Effective Date
Published Date
9/25/2026
10/8/2026

Department and Agencies

Department
Independent Agency
Agency
Securities and Exchange Commission
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