Could be huge for automated trading and general market data costs reduction. Let’s see where it settles. https://www.tradersmagazine.com/am/industry-supports-sec-market-data-rule/
The short story: The rules adopted today update and expand the content of NMS market data to include: (1) information about orders in share amounts smaller than the current round lot size (e.g., 100 shares); (2) information about certain orders that are outside of an exchange’s best bid and best offer (i.e., certain depth of book data); and (3) information about orders that are participating in opening, closing, and other auctions. Also: Competing consolidators, rather than the existing exclusive SIPs, will collect, consolidate, and disseminate certain NMS information. Effective in 60 days, but a phased transition plan begins in 2021 to avoid chaos.