Study guide
Function 4 accounts for 32 of the 150 scored questions and centers on the trading desk: short sales, quoting and market making, order handling duties owed to customers, trade reporting, and the surveillance systems that catch manipulation and insider trading. Expect questions that test both the underlying rule and what a supervising principal should do when a red flag appears.
Short Sales Under Regulation SHO
Regulation SHO governs short selling in equity securities, and supervisors are tested on three pillars: marking, locates, and close-outs. Every sell order must be marked long, short, or short exempt, and a seller is long only if it owns the security and can deliver it by settlement. Before accepting or effecting a short sale, the firm must locate the security, meaning it has borrowed the shares, arranged to borrow them, or has reasonable grounds to believe they can be borrowed in time for delivery; bona fide market making activity is excepted from the locate requirement, but the exception does not cover speculative proprietary shorting dressed up as market making. Threshold securities are those with aggregate fails to deliver at a registered clearing agency of 10,000 shares or more that also equal at least half a percent of shares outstanding, for five consecutive settlement days; once a firm has a fail position in a threshold security for 13 consecutive settlement days, it must close out the position by purchasing shares, and until it does, it may not accept further short sales in that security without a pre-borrow. Rule 204 separately requires prompt close-out of fails from short sales, generally by the morning after settlement date. Rule 201, the alternative uptick rule, is a circuit breaker: when a stock falls 10 percent intraday from its prior close, short sales may be executed only at a price above the current national best bid for the remainder of that day and the entire next trading day. Supervising principals monitor locate documentation, fail reports, and order marking accuracy, and they treat repeated marking errors by a trader like Tomas as an escalation event, not a clerical footnote.
Regulation NMS, Quoting, and Market Maker Obligations
Regulation NMS knits U.S. equity markets into a single national market system. The Order Protection Rule, Rule 611, prohibits trade-throughs, meaning executions at prices inferior to a protected quotation, which is an automated, immediately accessible quote at the top of an exchange's book; a firm routing an intermarket sweep order that simultaneously hits the better-priced quotes may execute the balance at its own price. The Access Rule caps fees for taking displayed quotes, and the Sub-Penny Rule sets the minimum quoting increment at one cent for stocks priced at one dollar or more, though recent SEC amendments permit a half-penny increment for certain tick-constrained stocks, so verify the current state of that change. Market makers register with FINRA or an exchange on a security-by-security basis and must maintain continuous two-sided quotations during regular hours. The firm quote rule obligates a market maker to execute orders at its displayed quote up to its displayed size; failing to honor a quote is called backing away and is a serious violation supervisors must investigate immediately. Excused withdrawal procedures exist for genuine circumstances such as system failures, and unexcused withdrawal from quoting can suspend a firm's market making privileges in that security. Alternative trading systems, including electronic communication networks, operate under Regulation ATS: they register as broker-dealers, file Form ATS, and face additional obligations, such as fair access, once volume thresholds are crossed. Third-market trading, meaning over-the-counter trading of exchange-listed securities, remains subject to the same best execution and trade reporting duties. Principals supervising a market making desk review quote quality, backing-away complaints, clearly erroneous trade filings, and compliance with registration in each quoted security.
Best Execution and Protecting Customer Orders
FINRA Rule 5310 requires a firm handling customer orders to use reasonable diligence to find the best market and execute at a price as favorable as possible under prevailing conditions. The factors are testable: the character of the market for the security, the size and type of transaction, the number of markets checked, and the accessibility of quotations. A firm that routes orders to a venue or wholesaler, including for payment for order flow, cannot let routing economics displace execution quality, and firms that do not check markets order-by-order must conduct regular and rigorous reviews of execution quality, at least quarterly, comparing venues they use against venues they could use. Related disclosures include quarterly public order routing reports and disclosure of payment for order flow practices to customers. Rule 5320, the successor to the Manning rule, prohibits a firm that holds a customer order from trading for its own account at a price that would satisfy that order without immediately executing the customer order at the same or better price. Two exceptions matter most: institutional accounts and large orders, generally 10,000 shares or more with substantial dollar value, may be handled on a not-held basis if the firm discloses the practice and gives the customer a meaningful chance to opt in to full protection; and a no-knowledge exception applies where information barriers genuinely separate the proprietary desk from the desk holding the customer order. Example: Rosa places a limit order to buy at 25.10, and the firm's proprietary desk buys at 25.10 for its own book. Unless an exception applies, Rosa's order must be filled at 25.10 or better, and her principal should expect surveillance to flag the sequence.
Trade Reporting, TRACE, and the Consolidated Audit Trail
Over-the-counter trades in equity securities, including exchange-listed stocks traded off-exchange, are reported to a FINRA Trade Reporting Facility or the OTC Reporting Facility as soon as practicable, and no later than 10 seconds after execution during reporting hours. In trades between two members, the executing party reports; in trades with a customer or non-member, the member reports. Late reporting, misreported capacity, and unreported trades are recurring exam fact patterns, and supervisors are expected to review trade reporting exception queues daily. Fixed income transactions are reported through TRACE, the Trade Reporting and Compliance Engine, which covers corporate bonds, agency debt, asset-backed and mortgage-backed securities, and U.S. Treasuries. The standard for most TRACE-eligible trades is as soon as practicable but no later than 15 minutes after execution; FINRA has adopted a framework to move toward one-minute reporting, but as of mid-2026 the 15-minute outer limit still applies, so confirm the current requirement when you study. The Consolidated Audit Trail, or CAT, is the industry-wide order lifecycle database: firms report the origination, routing, modification, cancellation, and execution of orders in NMS securities and OTC equities, generally by early the next trading day, with synchronized business clocks. CAT reporting accuracy is itself a supervised activity, meaning firms need procedures to verify submissions, correct rejected records promptly, and document the review. A useful mental model for the exam: equity trade reports feed public last-sale data measured in seconds, TRACE feeds bond price transparency measured in minutes, and CAT feeds regulatory surveillance measured in order lifecycles, and a principal is responsible for the firm's timeliness and accuracy in all three.
Manipulation, Insider Trading, and Prohibited Practices
SEC Rule 10b-5 prohibits fraud and deceit in connection with the purchase or sale of any security, and it anchors insider trading law: trading while in possession of material nonpublic information in breach of a duty, tipping others for a benefit, and misappropriating confidential information are all covered, and tippees inherit liability when they know or should know the tip breached a duty. The Insider Trading and Securities Fraud Enforcement Act requires broker-dealers to maintain written policies to prevent misuse of material nonpublic information, which in practice means information barriers between departments, watch lists for quiet monitoring, and restricted lists that halt proprietary trading and solicitation in a name. Civil penalties can reach three times the profit gained or loss avoided, and firms that fail to supervise face controlling-person liability. Rule 10b5-1 trading plans offer an affirmative defense when adopted in good faith before the person learns inside information; amendments effective in 2023 added cooling-off periods before trading can begin, generally longer for directors and officers, along with certification requirements and limits on overlapping plans. Front running, FINRA Rule 5270, prohibits trading ahead of imminent customer block transactions, with a block conventionally understood as 10,000 shares or a comparable dollar value. Rule 5240 prohibits coordinating quotes or trades to intimidate other market participants. Classic manipulation patterns to recognize: marking the close or open, wash sales and matched orders that create false volume, spoofing and layering with orders never meant to execute, and pump-and-dump distributions. Supervisors respond with surveillance reports, prompt escalation, documented investigations, and, where warranted, Rule 4530 reporting of internal conclusions.
Key terms
- Locate requirement
- — The Reg SHO duty, before effecting a short sale, to borrow, arrange to borrow, or reasonably believe the security can be borrowed in time for delivery; bona fide market making is excepted.
- Threshold security
- — An equity with aggregate fails to deliver of 10,000 shares or more, equal to at least 0.5 percent of shares outstanding, for five consecutive settlement days; persistent fails of 13 settlement days force a close-out.
- Rule 201 (alternative uptick rule)
- — A circuit breaker triggered by a 10 percent intraday decline that permits short sales only above the national best bid for the rest of that day and the next trading day.
- Protected quotation
- — An automated, immediately accessible top-of-book quote on an exchange that other markets may not trade through under Reg NMS Rule 611.
- Intermarket sweep order (ISO)
- — An order routed to execute against better-priced protected quotes simultaneously, allowing the sender to execute the remainder at its own price without a trade-through violation.
- Backing away
- — A market maker's failure to honor its displayed quote up to its displayed size, violating the firm quote rule.
- Best execution (Rule 5310)
- — The duty to use reasonable diligence to obtain the most favorable terms reasonably available for customer orders, backed by regular and rigorous reviews when routing is not assessed order-by-order.
- Rule 5320 (Manning rule)
- — The prohibition on trading for the firm's own account at prices that would satisfy a held customer order without executing that customer order at the same or better price.
- Trade Reporting Facility (TRF)
- — The FINRA facility for reporting over-the-counter trades in exchange-listed equities, generally within 10 seconds of execution.
- TRACE
- — FINRA's Trade Reporting and Compliance Engine for fixed income transactions, with most trades reportable as soon as practicable and no later than 15 minutes after execution as of mid-2026.
- Consolidated Audit Trail (CAT)
- — The regulatory database capturing the full lifecycle of orders in NMS securities and OTC equities, reported by firms with synchronized clocks, generally by early the next trading day.
- Rule 10b5-1 plan
- — A prearranged written trading plan providing an affirmative defense to insider trading when adopted in good faith before learning inside information, now subject to cooling-off periods and certification requirements.
Exam tips
- Anchor the reporting clocks: 10 seconds for OTC equity trade reports, 15 minutes for most TRACE-eligible bond trades as of mid-2026, and CAT order events generally due by early the next trading day.
- Rule 201 questions test duration as much as the trigger: a 10 percent intraday drop restricts short sales for the remainder of that day plus the entire next trading day.
- For Rule 5320, recall the two big escape hatches, institutional and large orders with disclosure and opt-in, and the no-knowledge exception, which works only with real information barriers.
- Distinguish a watch list, which is confidential and used for surveillance, from a restricted list, which openly restricts trading and solicitation; moving a name from watch to restricted often signals a deal became public.
- Best execution cannot be traded for payment for order flow; if a question shows routing decided purely by rebates, the answer almost always involves a 5310 failure.