Form ATS-N/OFA Filings

What Is SEC Form ATS-N/OFA?

SEC Form ATS-N/OFA is an amendment filing made under Rule 304 of Regulation ATS for alternative trading systems that trade NMS stocks. It is used by an NMS Stock ATS to publicly update certain operational disclosures on its Form ATS-N, particularly those related to order display and execution access and fair access requirements. During SEC review and ongoing operation, these disclosures help regulators and market participants understand how the ATS provides access to displayed orders and how it applies fair access standards.

This form type is typically filed when information required to be disclosed in Part III, Items 24 and 25 of Form ATS-N becomes inaccurate or incomplete. In that situation, the ATS files an Order Display and Fair Access Amendment on Form ATS-N no later than seven calendar days after the information change, using the specific amendment type “ATS-N/OFA.” For background on publicly available ATS-N filings, see the Form ATS-N Filings and Information page.

Form ATSN/-OFA supports transparency by ensuring that changes to how an ATS displays subscriber orders, provides execution access, or applies fair access policies are reflected in its public disclosures. These amendments are part of the Form ATS-N disclosure framework and are distinct from other Form ATS-N amendment types, which are selected based on the nature of the change and the applicable filing standard.

Key elements typically found in SEC Form ATS-N/OFA include:

• Name of the NMS Stock ATS and the broker-dealer operator
• Identification of the Form ATS-N Part and Item(s) being updated (typically Part III, Items 24 and 25)
• Description of changes related to order display and execution access disclosures
• Description of changes related to fair access disclosures
• Date the information became inaccurate or incomplete, and the amendment context
• Supporting attachments or marked copies, as applicable to the amendment content

SEC Form ATS-N/OFA Filing Deadlines

SEC Form ATS-N/OFA is event-driven and must be filed based on when certain required disclosures become inaccurate or incomplete. These timing requirements are intended to keep publicly available Form ATS-N information current and aligned with Regulation ATS disclosure obligations.

Key Things to Know About Form ATS-N/OFA Filing Rules

• NMS Stock ATS Scope: Form ATS-N/OFA applies to alternative trading systems that trade NMS stocks and are required to make public filings on Form ATS-N under Rule 304 of Regulation ATS.
• Seven-Day Amendment Timing: An Order Display and Fair Access Amendment must be filed no later than seven calendar days after information required to be disclosed in Part III, Items 24 and 25 becomes inaccurate or incomplete.
• Public Disclosure Framework: Form ATS-N/OFA is part of the public Form ATS-N disclosure regime and is intended to keep key operational access and fair access information current and available to regulators and market participants.
• Distinct Amendment Type: Form ATS-N/OFA is a specific amendment category and is separate from other Form ATS-N amendment types (e.g., updating, correcting, or material amendments). Each amendment filing selects only one “Type of Amendment” for that submission.
• Filing Visibility and Monitoring: Market participants commonly monitor ATS-N amendments alongside other ATS filings to track changes in access, order display, and fair access policies.

To track alternative trading system disclosures under Rule 304 of Regulation ATS, our Insights of SEC Filings tools help you monitor filings such as Form ATS‑N/OFA, which serve as