Nasdaq Updates Rule 4759 Data Source for Night Session

Nasdaq filed an immediately effective rule change with the Securities and Exchange Commission to amend Exchange Rule 4759, which describes sources of data used by the Nasdaq system.

The August 25 Federal Register notice says Nasdaq filed SR-NASDAQ-2026-067 on August 17. The change specifies that, during Nasdaq’s planned Night Session and subject to Equity 1, Section 1(a)(19), the exchange will use CQS and UQDF as the source of quotation data for the purposes covered by Rule 4759(a).

Nasdaq’s broader 23-hour trading framework was approved in April. The filing describes the Night Session as running between 9:00 p.m. and 4:00 a.m. ET on weekdays, beginning each week on Sunday evening. Nasdaq also describes a one-hour pause from 8:00 p.m. to 9:00 p.m. ET before the overnight session.

The exchange says the data-source disclosure is intended to promote transparency for order handling, routing, execution, and regulatory compliance processes during the Night Session.

Why it matters

Extended-hours equity trading depends on reliable quotation data and clear rules for how orders are handled outside the normal day session. Brokers and active traders need to know which data sources govern routing and compliance logic before overnight access goes live.

What to watch next

Watch for Nasdaq operational notices, Equity Data Plan readiness updates, and broker disclosures explaining which order types and symbols will be available overnight.