# 2026-12523: BYX Exchange Mirrors Cboe ISO Rule Update

2026-12523, Self-Regulatory Organizations; Cboe BYX Exchange, Inc.; Notice of Filing of a Proposed Rule Change To Amend Rule 11.9(d) To Permit an Intermarket Sweep Order (“ISO”) To Be Entered as a Non-Displayed Order and To Establish the Price Level at Which the System Will Consider an ISO Available for Other Orders To Be Entered, is a Federal Register notice from Securities and Exchange Commission published 2026-06-23; PRIA reads it as touching household money (as of 2026-06-30).

- Canonical: https://policyrisk.com/federal-register/2026-12523
- As of: 2026-06-30
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2026-12523
- Title: Self-Regulatory Organizations; Cboe BYX Exchange, Inc.; Notice of Filing of a Proposed Rule Change To Amend Rule 11.9(d) To Permit an Intermarket Sweep Order (“ISO”) To Be Entered as a Non-Displayed Order and To Establish the Price Level at Which the System Will Consider an ISO Available for Other Orders To Be Entered
- Type: Notice
- Agencies: Securities and Exchange Commission
- Citation: 91 FR 37451
- Published: 2026-06-23
- Effective: unknown
- Comments close: not stated
- Significant: no
- Touches household money: yes
- Regulation identifier numbers: none
- Last updated: 2026-06-30

## In one line

BYX Exchange Mirrors Cboe ISO Rule Update

## Summary

Cboe BYX Exchange is updating its rules to let traders enter Intermarket Sweep Orders (ISOs) as hidden (non-displayed) orders and set clear price levels for when these orders can be matched with others. This change helps traders act faster and smarter in the market, potentially improving trading efficiency. The new rules could start soon after the SEC reviews them, affecting anyone who trades on BYX and possibly impacting trading costs and speed.

## Effects PRIA read

- Hidden ISOs Allowed on BYX: benefit, medium. Cboe BYX will allow Intermarket Sweep Orders (ISOs) to be entered as Non-Displayed (hidden) orders. The change is proposed for implementation during the second half of 2026. If you trade on BYX, you can send ISO orders without displaying them, giving you a new option for hiding residual interest wh…
- Clear ISO Price-Level Rules by Session: benefit, low. The Exchange will codify when an ISO's limit price is considered available for other orders to join or for resting orders to re-price. Under proposed Rules 11.9(d)(1)-(3): during Regular Trading Hours (9:30 a.m.–4:00 p.m. ET) the ISO limit price is considered available; during the Early Trading Ses…
- Non-Displayed Orders Can Re-Price Multiple Times: benefit, medium. BYX will permit Non-Displayed Orders to re-price (slide) multiple times to more aggressive prices if the User elects that instruction. Each time a Non-Displayed Order is re-priced it receives a new timestamp, and the order will retain its original limit price regardless of the ranked price. The Exc…

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## Sources
- [2026-12523 on federalregister.gov](https://www.federalregister.gov/documents/2026/06/23/2026-12523/self-regulatory-organizations-cboe-byx-exchange-inc-notice-of-filing-of-a-proposed-rule-change-to)
- [2026-12523 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2026-06-23/pdf/2026-12523.pdf)

## Related
- [Previous: 2026-12521, Self-Regulatory Organizations; The Depository Trust Company; Notice of Filing a…](https://policyrisk.com/federal-register/2026-12521)
- [Next: 2026-12524, Self-Regulatory Organizations; Cboe BZX Exchange, Inc.; Notice of Filing of a P…](https://policyrisk.com/federal-register/2026-12524)
- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2026-12523 (as of 2026-06-30).