SEC approves Cboe BYX rule change allowing non-displayed ISOs and multi-slide orders

On Aug. 28 2026 the Securities and Exchange Commission issued Order No. 34-106229 approving Cboe BYX Exchange's proposed amendment (SR-CboeBYX-2026-026). The change permits Intermarket Sweep Orders (ISOs) to be entered as non-displayed orders and adds a mechanism for non-displayed orders to re-price repeatedly, binding all Exchange members and sponsored participants.

The amendment to Exchange Rule 11.9(d) authorizes a "Non-Displayed ISO" and establishes three sub-rules governing when the System will treat the ISO's limit price as available for new orders or for re-pricing. During Regular Trading Hours (9:30 a.m. to 4:00 p.m. ET) the limit price is available for new entries; during the Early Trading Session (4:00 a.m. to 8:00 a.m. ET), the Pre-Opening Session (8:00 a.m. to 9:30 a.m. ET), or the After Hours Trading Session (4:00 p.m. to 8:00 p.m. ET) the price is not made available. A further provision keeps the price available for after-hours execution if the order remains eligible.

The amendment to Rule 11.9(g)(4) expands "Non-Displayed Order Sliding." Users may now elect multiple price slides so that a non-displayed order re-prices each time the NBBO changes, receives a new timestamp, and is ranked at a more aggressive price without crossing a protected quotation. The order's original limit price remains unchanged.

The Commission found the proposals consistent with the Act and Section 6(b)(5), noting that no comment letters were received after the June 23 2026 notice and that comparable functionality exists at other national securities exchanges. The Commission concluded the changes provide greater flexibility, potentially increase liquidity, and support efficient price discovery.

Accordingly, the Commission ordered that the proposed rule change be approved, effective upon issuance of this order.