For each NMS stock, the national securities exchange identified as the primary listing exchange in the effective national market system plan or plans required under § 242.603(b). Use the current defined term “primary listing exchange.” Do not substitute the broader phrase “primary listing market” when stating the § 242.600 definition.
ReviewedEvidence1 sourceSectionPhrases & Idioms
Quick answer
Under Regulation NMS, the “primary listing exchange” for an NMS stock is the national securities exchange identified as such in the effective NMS plan or plans required under § 242.603(b).
Key details
Canonical FormPrimary Listing Exchange
Core MeaningFor each NMS stock, the national securities exchange identified as the primary listing exchange in the effective national market system plan or plans required under § 242.603(b).
Further guidance
History Boundary
Use the current defined term “primary listing exchange.” Do not substitute the broader phrase “primary listing market” when stating the § 242.600 definition.
Meaning
Under Regulation NMS, the “primary listing exchange” for an NMS stock is the national securities exchange identified as such in the effective NMS plan or plans required under § 242.603(b).
Usage Boundary
Use the current defined term “primary listing exchange.” Do not substitute the broader phrase “primary listing market” when stating the § 242.600 definition.
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.
Under current U.S. Regulation NMS, an “exchange market maker” is a member of a national securities exchange registered as a specialist or market maker under that exchange’s rules. Keep this definition tied to the Regulation NMS rule text; it does not define every market-making role outside that regulatory context.
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.
Actionable Indication of Interest 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.
Administrative Data is a current Regulation NMS defined term for specified administrative, control, and technical messages in the market-data plan framework.
Affiliate of a Subscriber is a current Regulation ATS defined term. This guide preserves the rule-specific meaning and boundary instead of replacing it with informal market shorthand.
Under current U.S. Regulation NMS definitions, aggregate quotation size is the sum of the quotation sizes of all responsible brokers or dealers communicating bids or offers in an NMS security at the same price. Treat this as a U.S. securities-regulation definition; it should not be generalized to unrelated uses of aggregate size or quotation outside Regulation NMS.
Alternative Trading System 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.
Auction Information is a current Regulation NMS term for specified, publicly disseminated exchange data generated leading up to and during securities auctions.
