Categorized by Order Size is a current Regulation NMS defined term. This guide keeps the reporting classification tied to the enumerated rule buckets rather than informal size labels.
ReviewedEvidence1 sourceSectionPhrases & Idioms
Quick answer
Under Regulation NMS, categorized by order size means dividing orders among the rule’s specified value and share-size categories.
Key details
Canonical FormCategorized by Order Size
Core MeaningDividing orders into the separate size categories specified by Regulation NMS, using dollar-value ranges together with less-than-a-share, odd-lot, and at-least-round-lot distinctions.
Further guidance
History Boundary
This page reflects the current reviewed 17 CFR § 242.600 definition and should be rechecked if Regulation NMS changes.
Meaning
17 CFR § 242.600 defines categorized by order size through the rule’s enumerated order-size buckets.
Usage Boundary
Use the rule-defined buckets for Regulation NMS reporting; do not substitute an informal small/medium/large classification.
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 Order Type is a current Regulation NMS defined term. This guide preserves the rule’s specific order-type classification rather than replacing it with a simplified trading glossary.
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.
Under current U.S. Regulation NMS, the “order size benchmark” measures the full displayed size of protected quotations at the national best bid or offer for the relevant side of an order, with special timing for midpoint-or-better limit orders and a cap at the order size. Use the detailed § 242.600 definition for reporting analysis; the benchmark depends on order side and timing and should not be flattened into a generic order-size metric.
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.
Block Size is a current Regulation NMS defined term. This guide preserves both alternative thresholds in the rule rather than reducing the definition to a single share-count test.
Under current U.S. Regulation NMS, a “covered order” is a rule-defined class of market and limit orders received by a market center, broker, or dealer under the timing and quotation conditions in § 242.600, subject to stated exclusions. The definition contains timing, NBBO, execution, and special-handling conditions and exclusions; do not reduce “covered order” to every market or limit order.
Under current U.S. Regulation NMS, a “customer limit order” is an order to buy or sell an NMS stock at a specified price that is not for a broker or dealer account, and it includes an order transmitted by a broker or dealer on behalf of a customer. Keep this definition tied to NMS stock, a specified price, and the rule’s express inclusion of orders transmitted by a broker or dealer on behalf of a customer.
Under current U.S. Regulation NMS, a “customer order” is an order to buy or sell an NMS security that is not for a broker or dealer account, subject to the rule’s stated market-value exclusions. Use the § 242.600 definition for rule-scoped analysis. The definition excludes orders meeting the stated market-value thresholds, so it should not be reduced to every order placed for a non-broker/dealer account.
