MEMX (Members Exchange) is a U.S. national securities exchange. Official equities hours on the MEMX hours page: Pre-Market 4:00 a.m., Market 9:30 a.m., Post-Market 4:00 p.m. ending 8:00 p.m. ET. No overnight listed. Founded 2019. Fees TODO:VERIFY. Not financial advice.
Official MEMX equities clocks
Source: MEMX Market Hours and Holiday Schedule at info.memxtrading.com/market-hours-and-holiday-schedule/, fetched 25 August 2026. That is MEMX's published table, not a copy of Arca. The MEMX rulebook defines Exchange Hours as 4:00 a.m. to 8:00 p.m. Eastern, Market Session / Regular Trading Hours 9:30 a.m. to 4:00 p.m., Pre-Market 4:00 a.m. to 9:30 a.m., Post-Market 4:00 p.m. to 8:00 p.m. Official About page (memx.com/overview): founded in 2019 by a diverse group of financial firms. Headquarters on MEMX contact materials: 111 Town Square Place, Suite 520, Jersey City, New Jersey. The SEC approved MEMX LLC's Form 1 as a national securities exchange on 4 May 2020 (Release 34-88806).
| Session | Start (ET) | End (ET) | On the MEMX hours page |
|---|---|---|---|
| Equities Pre-Market | 4:00 a.m. | 9:30 a.m. | Listed as 4:00A Pre-Market |
| Equities Market / Regular | 9:30 a.m. | 4:00 p.m. | Listed as 9:30A Market |
| Equities Post-Market | 4:00 p.m. | 8:00 p.m. | 4:00P Post-Market; 8:00P ends |
| Abbreviated equities post | 1:00 p.m. | 5:00 p.m. | Named early-close days only |
| Options Market | 9:30 a.m. | 4:00 p.m. | Select ETPs 4:15 p.m. |
| Overnight 23/5 | - | - | Not listed. Do not invent. |
On abbreviated equities days the same page starts post-market at 1:00 p.m. and ends it at 5:00 p.m. The 2026 holiday table names the U.S. federal set plus Good Friday, with footnotes for Friday 27 November 2026 and Thursday 24 December 2026 as abbreviated. This profile does not republish the full holiday grid. Options on that page are a different product. Do not mix the 4:15 p.m. select-ETP options close into the equities tape. See pre-market trading and the U.S. session hours 2026 hub.
MEMX 4:00 a.m. is MEMX's page, not a copied Arca row
Do not copy Arca's 4:00 a.m. onto a venue that does not publish it. MEMX does publish it. Equities Pre-Market starts at 4:00 a.m. ET because the MEMX hours page says 4:00A. That is the same early split as NYSE Arca, Nasdaq, and Cboe BZX/EDGX. It is not the 7:00 a.m. split used by NYSE Tape B/C, NYSE American, National, Texas, and Cboe BYX/EDGA. Tape A on NYSE has no continuous early book: orders queue from 6:30 a.m. into the 9:30 auction. IEX pre-market starts at 8:00 a.m. and IEX post ends at 5:00 p.m. MEMX post-market ends at 8:00 p.m.
If a chart paints pre-market from 4:00 a.m., MEMX can be matching. IEX is not matching yet. A 7:15 p.m. MEMX print is not an IEX print. Same symbol, different venue clock. Off-core prints typically carry sale condition T and are not last-sale eligible. The industry Core close remains 4:00 p.m. ET. Trading halts in regular hours still follow LULD and news-halt machinery; this page invents no halt counts.
No exchange overnight on MEMX
Arca, Nasdaq, and Cboe EDGX list 9:00 p.m. to 4:00 a.m. as planned for 6 December 2026 (SEC/SIP/DTCC), with a planned pause 8:00 p.m. to 9:00 p.m. and no overnight auction. That plan is not live as of 25 August 2026 ET. The MEMX hours page does not list overnight. This profile does not invent MEMX overnight and does not copy Arca's planned overnight onto MEMX. Broker overnight is ATS access, not a MEMX session. This page names no brokers and lists no broker hours.
Cboe C1 equity-options GTH is TBA. Index-options GTH on Cboe C1 is a different product. Neither clock is MEMX equities. Do not mix options GTH or a 23/5 slide into MEMX Exchange Hours.
Maker/taker, fees, and sizing
The MEMX home page describes a U.S. Equities Exchange (maker/taker) and a U.S. Options Exchange (maker/taker). That is a fee-structure label. Fee, rebate, access, and market-data numbers are TODO:VERIFY against the then-current MEMX fee schedule. This profile invents no ADV, no market-share percentage, and no rebate. MEMX is an NMS venue. It is not OTC Markets.
Example sizing only, not a trade: account $10,000, 1 percent risk equals $100. If the stop is $1.50 away, shares = floor(100 / 1.50) = 66, round down, on the risk calculator (crypto UI; treat the unit as shares, round down). PDT is not current law. The U.S. stock scanner is coming soon - not live, no subscription price on this page.
A 4:07 a.m. MEMX print is not an 8:15 a.m. IEX print and not a Tape A opening auction. MEMX does not run a 4:00 a.m. opening auction; Pre-Market is continuous matching inside Exchange Hours. The 9:30 a.m. open is an industry auction/cross clock, not a MEMX-only event. Level 2 depth on MEMX is venue depth, not the NBBO by itself. Do not invent MEMX share of NMS volume. Holiday calendars and 1:00 p.m. early closes are on the same MEMX hours page. Recheck that page for a named date rather than copying last year's footnote.
Ignore the stale MEMX production-facility page that still lists 7:00 a.m. pre-market. The official hours page is 4:00 a.m. to 8:00 p.m. ET.
FAQ
Does MEMX open at 4:00 a.m. ET?
Yes, for equities Pre-Market. The official MEMX hours page lists 4:00A Pre-Market. That is MEMX's clock, not a borrowed Arca row.
Does MEMX post-market run until 8:00 p.m.?
Yes, on a full equities day. Post-Market 4:00 p.m. to 8:00 p.m. ET. Abbreviated days cut post to 1:00 p.m. start and 5:00 p.m. end. IEX post ends 5:00 p.m. on a full day.
Does MEMX trade overnight or 23/5?
Not on the official hours page. U.S. exchange overnight 23/5 is planned for 6 December 2026 on named venues and is not live. This profile does not invent MEMX overnight.
Are MEMX fees on this page?
No. Maker/taker is the published structure. Dollar fees, rebates, and data charges are TODO:VERIFY. None invented.
Are these broker hours?
No. Official MEMX Exchange Hours only. A broker's extended window is not a MEMX session.
Educational only. Not financial, tax, or legal advice. Not a recommendation to trade MEMX or any session. Clocks as of the MEMX hours page read 25 August 2026 ET. Recheck the source before you size a print.