Periodic Auction Order Details

• Displayed continuous book orders will be executed first using price/time priority. Next will be Periodic Auction orders using size/time priority. Hidden continuous book orders will be executed third using standard BYX Priority.
• For orders less than 100 shares in symbols trading below $500 (based on Last Sale), Periodic Auction Only orders will be rejected upon entry. Periodic Auction Only orders initially entered as round or mixed-lot lot orders, but subsequently modified or partially traded to quantities less than 100 shares, will be prevented from initiating a Periodic Auction. Periodic Auction Eligible orders with quantities less than 100 shares will be restricted from initiating an auction.
• The auction process will not allow for broker preferencing.
• To prevent potential capacity or performance issues, the Exchange will cancel a Periodic Auction at the end of the Periodic Auction Period if it is unable to successfully process such Periodic Auction after three attempts.

At the end of the auction period, the price where the most shares will trade within the collar will be the auction price. If there are multiple prices where the same number of shares can trade, the price that leaves the smallest imbalance will be the auction price. If there are multiple prices where the same number of shares can trade and leave the smallest imbalance, the price closest to the volume-based tie breaker will be the auction price.

The volume-based tie breaker refers to the midpoint of the NBBO for a particular security where the NBBO is a valid NBBO. A valid NBBO refers to where there is both a NBB and NBO for the security and the NBBO is not crossed. The execution price of the auction must be within the NBBO and the Collared Price Range. The Collared Price Range varies based on the NBBO midpoint.