A detailed Regulation NMS term defining which securities are subject securities for an exchange or association member under specified volume and election conditions. This page is limited to the detailed Regulation NMS definition. Whether a security qualifies depends on the regulated entity and the rule’s volume/election conditions; the ordinary phrase “subject security” should not be substituted for that test.
ReviewedEvidence1 sourceSectionPhrases & Idioms
Quick answer
Under Regulation NMS, “subject security” is a rule-defined category whose test differs for an exchange and for a member of a national securities association and depends on the security, recent trading-volume thresholds, and specified § 242.602 elections.
Key details
Canonical FormSubject Security
Core MeaningA detailed Regulation NMS term defining which securities are subject securities for an exchange or association member under specified volume and election conditions.
Further guidance
History Boundary
This page is limited to the detailed Regulation NMS definition. Whether a security qualifies depends on the regulated entity and the rule’s volume/election conditions; the ordinary phrase “subject security” should not be substituted for that test.
Meaning
Regulation NMS defines “subject security” separately for a national securities exchange and for a member of a national securities association, using exchange-traded-security status together with specified trading-volume exclusions or elections under § 242.602(a)(5).
Usage Boundary
This page is limited to the detailed Regulation NMS definition. Whether a security qualifies depends on the regulated entity and the rule’s volume/election conditions; the ordinary phrase “subject security” should not be substituted for that test.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
Categorized by Security is a current Regulation NMS defined term. This guide keeps the meaning limited to the report-level separation of orders by each included NMS stock.
Corporate Debt Security is a current Regulation ATS defined term. This guide preserves the rule-specific meaning and boundary instead of replacing it with informal market shorthand.
Debt Security Under Regulation ATS is a current Regulation ATS defined term. This guide preserves the rule-specific meaning and boundary instead of replacing it with informal market shorthand.
Exchange-Traded Security is a current Regulation NMS defined term. This guide preserves the specific U.S. securities-rule scope instead of substituting an ordinary-language meaning.
Foreign Security Under Regulation AC is a current Regulation AC defined term. This guide preserves the rule-specific meaning and boundary instead of replacing it with informal market shorthand.
Listed Equity Security is a current Regulation NMS defined term. This guide preserves the specific U.S. securities-rule scope instead of substituting an ordinary-language meaning.
Nasdaq Security is a current federal securities-regulation defined term. This guide preserves the rule-specific definition and boundaries instead of replacing it with informal market shorthand.
Regulation NMS uses “NMS security” as a defined market-structure term tied to securities covered by specified transaction-reporting arrangements. It should not be treated as a generic synonym for every security traded electronically.
