Nasdaq PHLX amends Rule 3100 to incorporate CORE FIX protocols

On August 3, 2026, Nasdaq PHLX LLC filed a proposed rule change with the Securities and Exchange Commission, identified as Release No. 34-106140; File No. SR-PHLX-2026-51. The notice, published in the Federal Register on August 14, 2026 (FR Doc No. 2026-16855), seeks comments on the amendment to Equity 4, Rule 3100, which governs trading halts.

The Exchange proposes to revise the Limit Up-Limit Down provision in Rule 3100(b)(1)(A)(i)e.2.a) to add CORE FIX protocols to the language that governs how limit-priced orders entered through OUCH or CORE FIX protocols are repriced when price bands would otherwise place the order outside the permissible range. The change aligns the previously approved but inoperative Rule 3100 framework with the current operative Rule 3100 text. In addition, the Exchange will make conforming updates to Equity 4, Rules 3301A and 3312, correcting cross-references and replacing the term "Regular Market Session" with "Regular Trading Hours."

Implementation of the amendment is slated for August 10, 2026, consistent with coordinated updates to trading-halt procedures. The proposal includes the deletion of the currently operative Rule 3100 in its entirety and substitution with the revised rule text, without altering the substantive operation of the affected rules.

The filing cites authority under Section 19(b)(1) of the Securities Exchange Act of 1934 and Rule 19b-4, and asserts consistency with Section 6(b) and Section 6(b)(5) of the Act, which promote just and equitable trade principles, a free and open market, and investor protection. The Exchange believes the amendment will promote clarity, consistency, and transparency for its members.

The Commission is publishing this notice to solicit comments from interested persons, and the text of the proposed rule change is available on the Exchange's website at https://listingcenter.nasdaq.com/rulebook/phlx/rulefilings.