Strong Quoting and Trading Across Diverse Market Participants

Market Share

MEMX exchange market share (excluding TRF volume) was 5.2% in June with diverse participation across tapes. MEMX ranked #1 or #2 in market share in 404 symbols and ranked #4 or better in 3,063 symbols among 16 exchanges (Figure 1).

Strong Quoting Across Market Participants

MEMX has a diverse liquidity pool from market participants across the spectrum, including market makers and proprietary traders, banks with institutional order flow, retail investors, and agency brokers (Figure 2).

MEMX ranked #1 or #2 in time-at-NBBO in 3,089 symbols and ranked #4 or better in 6,056 symbols among 16 exchanges (Figure 3). This metric looks at the percentage of time each exchange is at the NBB or NBO during regular-hour trading for at least 100 displayed shares.

MEMX ranked #1 or #2 in NBBO setting in 1,832 symbols and ranked #4 or better in 4,228 symbols among 16 exchanges (Figure 4). This metric looks at the number of times each exchange is the first to establish a new NBB or NBO during regular-hour trading for at least 100 displayed shares.

Retail Trading and High Fill Rates

MEMX retail volume increased 6.1% month-over-month to 30.3 million average daily shares traded (Figure 5).

MEMX retail fill rates when limit orders were placed near the NBBO were 97% for order sizes between 100 and 9,999 shares, 94% for odd-lot sizes, and 90% for order sizes greater than 9,999 shares (Figure 6).

MEMX Options Update

MEMX Options’ pre-production environment is now available for firms to engage in launch preparation activities. Upon successful configuration, firms may enter and cancel orders, view market data, and receive drop copies within the pre-production environment.

On June 30, MEMX released new versions of its options specifications. Version 1.3 can be downloaded here. The change summary is listed below and all details are outlined in the Errata included in the download.

Version 1.3 changes:

• Added additional cancel and reject reason codes.
• Removed the Party Group field from several message types.

The FAQ addressing general technical and onboarding inquiries can be found here.

Market participants are encouraged to:

1. Establish physical connectivity:

1. • New connectivity via form or e-mail to connect@memx.com
   • Verify existing connectivity via email to mops@memx.com

1. Request logical sessions
2. Contact mops@memx.com for session configuration inquiries
3. Establish MEMX Customer Portal access

1. • Select MEMX Market Operations
   • Select MEMX Portal Access

1. Complete MEMX Options Exchange Membership Documents
2. Complete MEMX Options Market Data Order Form

Key Dates:

• Pre-production Environment: NOW AVAILABLE
• MEMX Options Development Environment (MODE): Monday, August 7
• User Acceptance Tests – Saturdays

• • August 19
  • August 26 (including OPRA)
  • September 9

• Production Phased Launch – Wednesdays

• • September 13 – Initial symbol tranche
  • September 20 – Second symbol tranche
  • September 27 – Remaining symbols