Cboe Speeds Up Closing Auctions with New Order Cutoffs
Published Date: 5/9/2025
Notice
Summary
Cboe BZX Exchange is tweaking its closing auction rules to make trading smoother and clearer. Market-On-Close orders will now lock in earlier at 3:55 p.m., and some order changes will have new cut-off times. Plus, the Exchange will share closing auction info more often, helping traders stay in the know without missing a beat.
Analyzed Economic Effects
3 provisions identified: 1 benefits, 2 costs, 0 mixed.
Closing Auction Data Every Second
Cboe BZX will continue publishing Closing Auction information every five seconds from 3:00 p.m. to 3:59 p.m., but will increase dissemination to every one second from 3:59 p.m. to 4:00 p.m. This provides more frequent Reference Price, Indicative Price, Auction Only Price, and reference buy/sell share information in the final minute before the close.
Market-On-Close Cutoff Moved Earlier
If you submit Market-On-Close (MOC) orders on Cboe BZX, the Exchange will reject any new MOC orders after 3:55 p.m. Eastern Time (previously 3:59 p.m.). That means you must send MOC orders to BZX by 3:55 p.m. on any trading day to participate in the Closing Auction.
Late Order Modifications Restricted
On Cboe BZX, MOC orders may not be modified or cancelled after 3:55 p.m. Eastern Time, and LOC and LLOC orders may not be modified or cancelled after 3:59 p.m. Eastern Time. These modification/cancellation cutoffs apply on each trading day ahead of the Closing Auction.
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