Pre-market share gains and new options active risk feature

Expanded Pre-market Hours; Options Active Risk Feature Improves Quoting

Equities Exchange Highlights

The SIP operating committees recently announced a proposed model for 24-hour trading from Sunday at 8 p.m. to Friday at 8 p.m. ET with a brief technical pause at the end of each trading day at 8 p.m. The pause will be no longer than 1 hour. Implementation is subject to SEC approval. Additional considerations include:

• Availability of symbol directory messages (corporate actions) on the SIP feed, which the SIPs have agreed to implement on or before the proposed extension of hours. See MEMX recommendation.
• Availability of TRFs
• Availability of DTCC for real-time clearing
• Which investor protections will function in a 24-hour market (i.e. LULD, clearly erroneous rules, MWCBs). See the MEMX Member Poll.

Figure 1 shows the rise in pre-market activity between 4:00 a.m. to 9:30 a.m. ET in recent months. Pre-market average daily volume increased to 1.3 billion shares (7.5% of industry volume) in May 2025, up from 636 million shares (5.1% of industry volume) in May 2024.

Figure 2 shows the industry volume mix in 30-minute time bins. The first 30 minutes from 4:00 a.m. to 4:30 a.m. (ET) was 0.63% of industry volume in May 2025 (and 110 million average daily volume), up from 0.31% of industry volume in May 2024. Activity starts to ramp up around 7:00 a.m., ahead of the opening auction at 9:30 a.m.

Figure 3 shows MEMX market share in 30-minute time bins before (May 1-16) and after (May 19-30) the launch of 4:00 a.m. trading. MEMX has seen pre-market market share gains since expanding trading to 4:00 am on May 19th. We expect firms to continue to ramp up pre-market trading on MEMX in the upcoming month.

In May, the pre-market add volume mix occurring on MEMX was 60% retail and 75% sub-$1 priced stocks. 50% of MEMX volume was retail and sub-$1 in the pre-market session.

Options Exchange Highlights

MEMX Options average daily contracts increased 160% year-over-year to 1.82 million in May. MEMX Options total market share was 3.6% and regular electronic market share was 6.5%.

MEMX Options continues to exhibit strong quote performance. Figure 6 shows MEMX trading and quoting data in the most active options contracts on the last day of the month. 

For example, in SPY on May 30th, MEMX options regular electronic market share was 5.8% and we ranked second among 18 exchanges in quote performance. MEMX quoted 75.4% of the time at the best bid or ask when an options regular electronic trade occurred in SPY. In the top 15 underlyings, MEMX mostly ranked first or second in quote performance among all exchanges.

MEMX Options offers a unique active risk control feature to improve quote performance by helping market makers better manage risk using internal metrics. The functionality provides a real time conversation between a trading firm and MEMX about where they stand in terms of their risk profile and trading activity. In contrast, standard risk controls monitor risk passively using defined period-of-time techniques—a less flexible approach that can leave market makers more exposed.

MEMX’s experience with active risk protections also highlights the ways in which an options exchange can facilitate high-quality quoting by market makers without impairing access to displayed liquidity. See MEMX comment letter on IEX options.

1 Regular electronic market share includes continuous trading in single-leg options (excludes auctions, floor, and complex trades).

2 Quote performance is calculated based on the percent of time an exchange was quoting at the best bid or ask when an options regular electronic trade occurred. The higher the percentage, the greater an exchange’s quote performance.

3 Rank among 18 options exchanges.

MEMX Member Poll

As a framework for 24-hour trading takes shape, MEMX is playing an active role in the regulatory conversations to help achieve industry consensus and a harmonized approach.

To ensure varied perspectives inform the transition to 24-hour trading, we’re conducting a quick poll to gauge sentiment around several key issues. Take the Poll and stay tuned for our analysis.