FINRA Updates ADF Rules to Feed Odd-Lot Quotes Into the SIP

FINRA has filed an immediately effective rule change to amend Rule 6272 and make the Alternative Display Facility, or ADF, compatible with the SEC’s new odd-lot quotation regime under Regulation NMS. The change was published by the SEC on March 30, 2026, with an operative date of April 27, 2026.

The practical shift is simple: ADF market participants will now have to provide specified odd-lot quotation information to FINRA so it can be passed to the securities information processors, or SIPs, for consolidated dissemination. The filing adds a new paragraph requiring participants to submit their highest-priced odd-lot buy order at or above the national best bid and their lowest-priced odd-lot sell order at or below the national best offer. In the new framework, that best odd-lot information becomes part of the broader push to surface liquidity that used to sit outside traditional round-lot quote displays.

FINRA noted that the ADF historically handled quotations sized at at least one round lot, so the rule had to change to reflect the SEC’s newer market-data requirements.

Why it matters

Odd lots now represent a meaningful share of activity in many higher-priced U.S. stocks. Bringing that information into consolidated feeds can improve price discovery for traders who rely on public data rather than direct-feed products.

What to watch next

The near-term question is how consistently brokers, vendors, and data users incorporate the new odd-lot fields into screens and routing logic after the April 27 operative date. The rule change is only useful if the market actually displays and uses the added information.