Cboe BZX Delays Wild Market Openings for Fairer Price Discovery
Published Date: 1/27/2026
Notice
Summary
Cboe BZX Exchange is proposing a new rule to delay the opening auction when the market is acting wild. This pause helps find better prices that truly match what's happening in the market, so traders get fairer deals. If approved, this change will affect all traders using BZX and could improve how stocks open each day without extra costs or delays.
Analyzed Economic Effects
4 provisions identified: 3 benefits, 1 costs, 0 mixed.
Opening Auction May Be Delayed Up to 9:34:30
The Exchange would delay the Opening Auction when the Indicative Price falls outside the Collar Price Range. The system will check every second from 9:30:00 to 9:30:05, then may widen collars and continue checks up to 9:34:30, so the opening may occur later than 9:30 a.m. ET.
Aims to Reduce LULD Halts and Improve Bands
The Exchange states the change should produce fewer limit up-limit down (LULD) halts and more accurate Collar Price Ranges because opening prices and LULD reference prices will be based on more current market conditions rather than stale closing prices.
Odd-Lot Executions Can Set Opening Price
The Exchange would redefine the BZX Official Opening Price so that either a round-lot or an odd-lot execution from the Opening Auction can set the official opening price disseminated to the consolidated tape. That official opening price will continue to be used to help set LULD reference prices and bands.
Order Submission and Cancellation Timing Rules
Under the proposal, LOO and MOO orders must be submitted by 9:28 a.m.; additional LOO/MOO orders after 9:28 will be rejected. Regular Hours Only (RHO) market orders are rejected from 9:28 a.m. until the Opening Auction concludes, while late-limit-on-open (LLOO) orders may be submitted from 9:28 a.m. until the Opening Auction concludes. Eligible Auction Orders may not be cancelled or modified from 9:28 a.m. until the Opening Auction concludes, except RHO limit orders may be modified but not cancelled.
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