Definitions
References to terms defined in this section will be italicized and underlined within the document.
Eligible Auction Orders: On-Open and On-Close orders that are entered prior to the cut-off or Late-Limit orders entered after the cut-off for an Opening/Closing Auction. RHO orders that are entered prior to 9:30 a.m. ET. All orders entered prior to the auction match for an IPO/New Issue/Halt Auction.
Final Last Sale Eligible Trade: The last trade during regular market hours (9:30AM - 4PM) on the Cboe BZX Exchange if the trade was executed within the last one second prior to either the Closing Auction or trading in the security being halted/paused. Otherwise, the last trade reported to the Consolidated Tape and received by Cboe during regular trading hours and, where applicable, prior to trading in the security being halted/paused will be used. If there is no qualifying Final Last Sale Eligible Trade for the current day, the official previous closing price will be used.
Volume Based Tie Breaker: The midpoint of the NBBO, if valid. The NBBO is valid when,
- There is both an NBB and NBO for the security, and
- The NBBO is not crossed, and
- The midpoint of the NBBO is less than the Maximum Percentage away from both the NBB and NBO.
In the event the NBBO is not valid the price of the Final Last Sale Eligible Trade will be used.
For IPO Auctions, the issue price will be used.
Maximum Percentage: The Maximum Percentage will vary depending on the price of the NBBO Midpoint.
| NBBO Midpoint Price | Maximum Percentage |
|---|---|
| Less than or equal to $25 | 5% |
| Greater than $25 but less than or equal to $50 | 2.5% |
| Greater than $50 | 1.5% |
Collar Midpoint: The Volume Based Tie Breaker for all applicable auctions, except for New Issue Auctions in ETPs, for which the Collar Midpoint will be set to the issue price. Effective 09/21/26, this exception will be removed.
Collar Price Range: The range from the set percentage below the Collar Midpoint to the set percentage above the Collar Midpoint. Specifically, the Collar Price Range will be determined as follows:
- Where the Collar Midpoint is $25.00 or less, the set percentage is 10%.
- Where the Collar Midpoint is greater than $25.00 but less than or equal to $50.00, the set percentage is 5%.
- Where the Collar Midpoint is greater than $50.00, the set percentage is 3%.