MEMX 23×5 Trading

Status

RULES FILED / NOT YET OPERATING

Target launch

December 6, 2026, subject to readiness conditions and a follow-up MEMX implementation filing

Overnight

9:00 PM–4:00 AM ET

Daily pause

8:00 PM–9:00 PM ET

Eligible products

Equity securities and UTP exchange-traded products

Planned trading day

• Overnight: 9:00 PM–4:00 AM ET
• Pre-Market: 4:00 AM–9:30 AM ET
• Regular Market: 9:30 AM–4:00 PM ET
• Post-Market: 4:00 PM–8:00 PM ET
• Pause: 8:00 PM–9:00 PM ET for daily maintenance, testing, corporate-action processing and trade processing.

The trading week is designed to begin Sunday at 9:00 PM ET when the following day is a business day.

Orders and trade dates

• All orders resting on the MEMX book at 8:00 PM are cancelled before the next trading day begins.
• MEMX begins accepting orders again at 9:00 PM. Orders that remain open at 4:00 AM are not automatically cancelled and may remain eligible in later sessions according to their instructions.
• A Day Order entered during the Overnight Session may remain eligible through the Overnight, Pre-Market and Regular Market sessions and expires at 4:00 PM if unexecuted.
• MEMX says all order types currently accepted during its Pre-Market Session will also be accepted during the Overnight Session. Pegged orders in extended sessions will require a limit price.
• Trades at or after 9:00 PM are assigned the following day’s trade date. MEMX’s FAQ shows 9:00 PM–11:59 PM trades using the next calendar day as trade date and midnight–4:00 AM trades using that same calendar day.
• MEMX plans to support routing during the Overnight Session to eligible NMS exchanges.

Launch conditions

MEMX’s current FAQ targets December 6, 2026, but the Overnight Trading Session is not live. The SEC filing says MEMX will not begin overnight operation until the Equity Data Plans are ready to collect, consolidate, process and disseminate quotation and transaction information throughout the session and MEMX confirms its own regulatory readiness.

Before launch, MEMX must make a subsequent filing confirming those conditions and then announce the implementation and go-live date by Trader Alert.