2026-20805NoticeWallet

Nasdaq PHLX Fixes Trade Goofs for 23-Hour Trading Madness

Published Date: 10/13/2026

Notice

Summary

Nasdaq PHLX is updating its rules to handle mistakes in stock trades better during new 23-hour, 5-day trading sessions. This change affects traders and brokers by adding clear price limits overnight to prevent big errors. The new rule kicks in right away, helping keep markets fair and smooth without extra costs.

Analyzed Economic Effects

4 provisions identified: 4 benefits, 0 costs, 0 mixed.

Overnight LULD Hours Block CEE Review

If a trade is executed during LULD Protected Hours (which the rule defines to include Market Hours and Overnight Protected Hours), that trade generally will not be eligible for clearly erroneous (CEE) review. The rule defines Overnight Protected Hours as the period from 9:00 p.m. ET through 4:00 a.m. ET and extends the existing Market Hours restriction to those overnight hours.

Overnight Price Bands Set at ±20%

The Overnight Price Bands that will apply during Overnight Protected Hours were initially established as temporary static bands 20% above and 20% below two reference points. The Exchange will incorporate an "Overnight Percentage Parameter" into its clearly erroneous rules so the overnight percentage parameter applies to trades during Overnight Protected Hours.

Rights/Warrants Keep CEE Eligibility Overnight

For NMS stocks not subject to the LULD Plan (for example, rights and warrants), the Exchange will extend eligibility for clearly erroneous review to transactions executed during Overnight Protected Hours and apply the same Numerical Guidelines that now apply to Pre-Market and Post-Market Hours.

Rule Operative with 23/5 Trading on Dec 6, 2026

The Exchange states this rule amendment would become operative at the start of industry-wide 23/5 Trading, which is scheduled to commence on December 6, 2026. The change was filed on September 28, 2026, and the Commission published the notice soliciting comments with a deadline of November 3, 2026.

Personalized for You

How does this regulation affect your finances?

Personalize government policy and PRIA will tell you what this federal register document means for your household, plus every other regulation we track. PRIA reads each provision against your financial profile to show you exactly what matters to your wallet.

Key Dates

Published Date
Effective Date
10/13/2026
12/6/2026

Department and Agencies

Department
Independent Agency
Agency
Securities and Exchange Commission
Source: View HTML

Related Federal Register Documents

Previous / Next Documents

Back to Federal Register