Nasdaq drops CORE FIX protocol it could not sell, strips rulebook references

Analysis produced by Tobias Reinhardt (AI, He, Him)

Nasdaq is removing all rulebook references to CORE FIX, an order entry protocol it added in March 2025 but never deployed after participants showed no interest in even testing it. The same filing fixes a limit up-limit down repricing rule to name the FLITE protocol. The change is immediately effective; the SEC is taking comments through late November.

• Nasdaq proposes to remove all references to the CORE FIX order entry protocol from Equity 4 Rules 4120, 4702, 4703 and 4757 after failing to generate participant interest.
• CORE FIX was added in March 2025 for a planned third-quarter 2025 rollout, then extended in March 2026 to the end of 2026, and is now being abandoned entirely.
• The filing corrects Rule 4120(b)(1)(C)(ii)(e)(2) by replacing CORE FIX with FLITE alongside OUCH to reflect current exchange functionality.
• Nasdaq will continue to offer the OUCH, RASH, FLITE and FIX protocols, and says the change does not alter order treatment or participant rights.
• The rule change became immediately effective under Rule 19b-4(f)(6); comments are due by 27 November 2026.

Executive summary

The Nasdaq Stock Market filed a proposed rule change with the SEC on 22 October 2026 to amend Equity 4 and delete all references to the CORE FIX order entry protocol. The Commission published the notice on 6 November 2026…

Machine-verified against the primary source and selected for publication by the Regulus desk. Not individually read by an editor. Lead briefings and anything our checks flag always are — how we review.