Effective October 5, 2026, Cboe BZX Equities Exchange will implement changes related to the opening auction process for primary listings.

The opening auction process will facilitate achieving the best possible auction when the auction collar is based on the previous trading day’s closing price and the maximum number of shares that can be matched is at a price outside the defined collar range. This circumstance typically occurs with a significant overnight price change.

Opening auctions will no longer be required to occur immediately at 09:30:00 a.m.

Opening auction collars will sometimes be widened periodically to allow the opening auction to occur at the best possible price.

Currently, opening auction collars are established around a reference price, with the opening auction occurring within the established collars at 09:30:00 a.m. The opening auction collar reference price is the midpoint of the prevailing NBBO unless the NBBO is invalid (crossed, missing, or too wide). If the NBBO is invalid, currently the Final Last Sale Eligible Trade (FLSET) is used as the collar reference price. The FLSET is equal to the previous day’s closing price and collars are set around that price.

The updated opening auction process will reduce the risk of using a FLSET-established opening auction collar which may result in an opening price at 09:30:00 a.m. that deviates significantly from the Indicative Price, which is the price at which the most shares can be traded.

On the effective date, if at 09:30:00 a.m. the midpoint of the NBBO cannot be used as the opening auction collar reference price, then the collar range set by the FLSET will be compared to the current auction Indicative Price. If the Indicative Price is outside the established collars, the opening auction will be extended. If the Opening Auction is extended, Auction Update messages will continue to be disseminated every 5 seconds after 09:30 a.m.

In the case the opening auction is extended, the auction will be re-tried at the following times:

• 09:30:01 a.m.
• 09:30:02 a.m.
• 09:30:03 a.m.
• 09:30:04 a.m.
• 09:30:05 a.m.

At each of these times, the opening auction collars will be re-evaluated based on changes to the NBBO or on trades occurring after 09:30:00 a.m. which allow a new collar reference price to be established. If the NBBO is valid or if the Indicative Price falls within the opening auction collars set by the FLSET, then the opening auction will be conducted.

If the FLSET is still being used as the collar reference price and the Indicative Price is still outside of the established auction collars at 09:30:05 a.m., then the opening auction will be further extended. At 09:30:05 a.m., the upper or lower opening auction collar price will be widened by an amount that is 5% of the FLSET towards the Indicative Price at periodic time intervals until the Indicative Price is within the collars or the maximum number of extensions is exhausted. If at any time the Indicative Price is within the collars, the opening auction will be conducted.

Additionally, if at any time there is no crossing interest in the auction, the security opens immediately using the FLSET as the opening price.

The 5% widening of the upper or lower opening auction collar will occur at the following times:

• 09:30:05 a.m.
• 09:30:30 a.m.
• 09:31:30 a.m.
• 09:32:30 a.m.
• 09:33:30 a.m.
• 09:34:30 a.m.

At 09:34:30 a.m., the opening auction will conclude using the opening auction collars present at that time.

Should the opening auction be extended, the following eligible order types will be accepted after 09:30:00 a.m.:

• Continuous book orders
• Regular Hours Only limit orders (treated as Late-Limit-On-Open (LLOO) orders)
• LLOO orders (treated in the same manner as LLOO orders between 09:28:00 a.m. and 09:30:00 a.m.)

This functionality is currently available to test in the BZX certification environment.