# 2025-04328: Late-Night Options Auctions Get a Clarity Boost from Nasdaq ISE

2025-04328, Self-Regulatory Organizations; Nasdaq ISE, LLC; Notice of Filing and Immediate Effectiveness of Proposed Rule Change To Amend Its FLEX Trading Rules, is a Federal Register notice from Securities and Exchange Commission published 2025-03-18, effective 2025-03-07 (as of 2026-06-08).

- Canonical: https://policyrisk.com/federal-register/2025-04328
- As of: 2026-06-08
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2025-04328
- Title: Self-Regulatory Organizations; Nasdaq ISE, LLC; Notice of Filing and Immediate Effectiveness of Proposed Rule Change To Amend Its FLEX Trading Rules
- Type: Notice
- Agencies: Securities and Exchange Commission
- Citation: 90 FR 12577
- Published: 2025-03-18
- Effective: 2025-03-07
- Comments close: not stated
- Significant: no
- Touches household money: no
- Regulation identifier numbers: none
- Last updated: 2026-06-08

## In one line

Late-Night Options Auctions Get a Clarity Boost from Nasdaq ISE

## Summary

Nasdaq ISE just updated its FLEX trading rules to clear up what happens when FLEX auctions run past market closing time. This change affects traders using FLEX options and kicks in right away, making trading smoother and more predictable. The SEC is open to feedback for the next 60 days, but the new rules are already in action!

## Effects PRIA read

- FLEX Auction Timing Clarified: benefit, low. If you trade FLEX options on Nasdaq ISE, the exchange changed its rules to clarify what happens when a FLEX auction runs past the market close. The change took effect immediately when filed on March 7, 2025, and the SEC is accepting public comments through April 8, 2025.

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## Sources
- [2025-04328 on federalregister.gov](https://www.federalregister.gov/documents/2025/03/18/2025-04328/self-regulatory-organizations-nasdaq-ise-llc-notice-of-filing-and-immediate-effectiveness-of)
- [2025-04328 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2025-03-18/pdf/2025-04328.pdf)

## Related
- [Previous: 2025-04327, Self-Regulatory Organizations; Cboe BZX Exchange, Inc.; Notice of Filing of a P…](https://policyrisk.com/federal-register/2025-04327)
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Source: PRIA, https://policyrisk.com/federal-register/2025-04328 (as of 2026-06-08).