Introduction

Welcome to Order Entry, Routing, and Execution: the rules that govern how a broker-dealer (BD) controls trader activity, makes markets, accepts and routes orders, complies with short-sale obligations, achieves best execution, manages market access risk, and supervises behavior during volatility halts. This unit is the trading-desk supervision core of Function 4 on the Series 24 exam.

Exam Weight: Part of 21% (~32 questions across Function 4)

What You'll Learn

In this unit, you'll cover:

• Trader Mandates and Aggregation Units: How a firm defines each trader's authority through written trader mandates (products, position limits, loss limits, counterparties, hours), and how a firm uses aggregation units under Reg SHO to net long and short positions separately on different desks for short-sale marking
• Market Making and Quoting Activities: Registration, two-sided continuous quotations within the Designated Percentage, the 20-business-day suspension for unexcused withdrawals, passive market making during a Reg M restricted period, and the bright-line ban on issuer payments for market making
• Regulation SHO Short Sales: Order marking (long, short, short exempt), the locate requirement before order entry, close-out windows for fail-to-deliver positions, and the alternative uptick rule (10% intraday decline trigger)
• Best Execution and Reg NMS: The regular and rigorous review standard for best execution, the Order Protection Rule that prohibits trade-throughs of automated protected quotations, execution-quality reports vs. order-routing reports, and the sub-penny rule for NMS quotations
• Market Access Rule: The required pre-trade financial and regulatory controls, prohibition on unfiltered (naked) sponsored access, and the annual CEO certification requirement
• Volatility Pauses (LULD and MWCB): Single-stock LULD bands that double in opening/closing windows, the 15-second / 5-minute pause mechanic, and the three-level Market-Wide Circuit Breaker (7%/13%/20% S&P 500 drops)
• Prohibited Trading Practices: Manipulative quoting, back-away prohibitions, anti-coordination, front running of block transactions, trading ahead of research, Manning (front-running prohibition for customer orders), order-adjustment of GTC orders, and the OTC quotation-initiation framework
• Escalation Upon Discovery of Prohibited Activity: The supervisor's duty to recognize, investigate, and escalate through internal compliance and external reporting channels (regulatory event reporting, SAR, exchange referrals), and how a failure to escalate can become an independent supervisory-system failure

Why This Matters

The Series 24 exam tests three principal-level questions on this material:

• Whether the firm has structural controls that constrain trading activity to the right products, sizes, venues, and risk limits (trader mandates, aggregation units, market-access controls, Reg SHO marking)
• Whether the firm complies with the marketplace rules that govern quoting, routing, and execution (Reg NMS protected quotations, the best-execution rule, market-maker quotation and withdrawal obligations, LULD/MWCB halt compliance)
• Whether the firm detects, investigates, and escalates prohibited activity (spoofing, layering, front running, Manning violations, breakpoint avoidance, locked/crossed quoting) and documents the supervisory response

A firm that allows a trader to flip between aggregation units to mark a covered short as long violates Reg SHO; a firm that fails to flag a customer order routed away from the protected NBBO violates the Order Protection Rule; a firm whose CEO does not certify the market-access controls fails the market-access rule outright. The exam pairs these because the rulebook does.

Let's start with the foundational supervisory structure that constrains every trading decision: trader mandates and aggregation units.