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Series 23: Trading and Market Making

Try 10 focused Series 23 questions on Trading and Market Making, with explanations, then continue with the full Securities Prep practice test.

Series 23 Trading and Market Making questions help you isolate one part of the FINRA outline before returning to a mixed practice test. The questions below are original Securities Prep practice items aligned to this topic and are not copied from any exam sponsor.

Open the matching Securities Prep practice route for timed mocks, topic drills, progress tracking, explanations, and the full question bank.

Topic snapshot

ItemDetail
ExamFINRA Series 23
Official topicFunction 4 — Supervision of Trading and Market Making Activities
Blueprint weighting28%
Questions on this page10

Sample questions

Question 1

A general securities principal supervises an equity desk that makes markets in an NMS stock. The listing market declares a limit up-limit down trading pause, but one vendor feed used by the desk still shows the stock as open and traders can still attempt manual entries. Several customer orders are waiting, and the desk wants the least disruptive response that still meets supervisory obligations. What is the best immediate supervisory action?

  • A. Allow manual agency orders but prohibit principal trades until the vendor feed updates.
  • B. Let traders continue entering quotes if a supervisor reviews each entry individually during the pause.
  • C. Suspend quoting and order entry in the symbol, confirm the pause through an authoritative market-status source, escalate the stale feed under the firm’s WSPs, and document the incident before reopening activity.
  • D. Wait for trading to resume, then investigate the stale feed as part of the desk’s next routine review.

Best answer: C

Explanation: A trading pause requires an immediate stop on desk activity in the affected symbol plus prompt verification, escalation, and documentation of the control failure.

When a LULD pause or similar market restriction applies, the desk must stop quoting and order entry in the affected security rather than rely on a delayed internal feed. The principal should verify status through an authoritative source, escalate the control issue, and document the response before trading activity resumes.

The core supervisory issue is that an external market restriction overrides the desk’s stale internal status display. Once the principal knows a LULD trading pause is in effect, the proper response is to immediately prevent quoting and order entry in that symbol, verify the restriction through an authoritative market-status source, and escalate the feed or system exception under the firm’s WSPs. That response addresses both market-conduct risk and the control failure that allowed attempted entries during a pause.

Customer interest can remain pending, but the desk should not keep entering quotes or routing orders into a paused market just because one vendor feed is delayed. A manual workaround is not a substitute for honoring the restriction. The key takeaway is that the principal must impose the stop, verify, escalate, and document right away rather than defer review.

  • Agency-only trading fails because a trading pause restricts desk activity in the symbol, not just proprietary trading.
  • Manual supervisor approval fails because human review does not cure the fact that the market is paused.
  • Delayed investigation fails because the control problem requires immediate escalation and documentation, not a later routine review.

Question 2

Under a typical fully disclosed clearing arrangement, which activity is generally the responsibility of the carrying firm rather than the introducing firm?

  • A. Maintaining custody and settlement records for customer positions
  • B. Supervising registered representatives’ recommendations
  • C. Conducting branch inspections and OSJ supervision
  • D. Approving new accounts and suitability determinations

Best answer: A

Explanation: The carrying firm typically performs the back-office clearance, custody, and recordkeeping functions tied to settlement and customer positions.

In a fully disclosed arrangement, the carrying firm usually handles the operational back-office functions of clearing and carrying customer accounts. The introducing firm generally remains responsible for front-end supervision, including account approval, sales practice oversight, and branch supervision.

The core distinction is that the introducing firm typically manages the customer relationship and supervises associated persons, while the carrying firm performs clearing and custody functions under the clearing agreement. In trade processing and clearance, the carrying firm commonly maintains customer securities and funds, processes settlement, and keeps the related custody and position records. By contrast, the introducing firm generally handles account opening review, suitability or Reg BI-related supervision, and oversight of representatives and branch activity. A good Series 23 shortcut is to separate customer-facing supervision from back-office clearance and custody. The closest distractors involve supervisory duties that usually remain with the introducing firm, even when another firm carries the accounts.

  • New account approval is typically an introducing-firm supervisory function, not a core carrying-firm clearance duty.
  • Recommendation oversight stays with the firm supervising the registered representatives and customer interactions.
  • Branch supervision is part of OSJ and personnel oversight, which belongs to the introducing firm’s supervisory structure.

Question 3

A firm’s WSPs do not require any principal check that current issuer information has been reviewed before traders publish priced quotations in non-exempt OTC equity securities. An inspection finds the desk has been entering two-sided quotations in a thinly traded penny stock on an interdealer quotation system with no file showing the required issuer-information review. What is the most likely immediate consequence?

  • A. Withdraw the quotations until issuer review is documented.
  • B. Reverse completed trades as clearly erroneous.
  • C. File CAT corrections for the displayed quotes.
  • D. Send penny stock disclosures to prior purchasers.

Best answer: A

Explanation: Without documented support that the OTC security is eligible for a priced quotation, the firm should stop displaying the quotes.

The immediate issue is quotation eligibility, not trade cancellation or customer paperwork. If the firm cannot show the required issuer-information review for a non-exempt OTC penny stock, it should stop publishing the priced quotation until the condition is satisfied.

For non-exempt OTC equity securities, a firm must have a valid basis to publish a priced quotation, including the required review of current issuer information when applicable. In this scenario, the supervisory failure is that traders could enter two-sided OTC quotes without evidence that the review occurred. That makes the most immediate consequence operational and regulatory: the firm should withdraw the quotation rather than continue displaying it.

Completed trades are not automatically unwound just because quotation controls were deficient, and customer penny stock disclosures address a different obligation. CAT also concerns order-event reporting, not whether the firm was permitted to publish the OTC quote in the first place. The key takeaway is that a quotation-control gap first affects the firm’s ability to continue quoting the security.

  • Trade reversal is too far downstream; missing quotation-review documentation does not automatically rescind executed trades.
  • CAT reporting misses the issue because CAT does not cure a failure to establish OTC quotation eligibility.
  • Penny stock disclosure addresses customer sales-practice requirements, not the threshold permission to publish the quote.

Question 4

A principal reviews a desk plan for a 1,200-share customer market buy order in NMS stock XYZ. The desk wants to execute the balance internally at $25.00. Assume each displayed offer below is a protected, automated quotation, and ignore any broader best-execution analysis.

Displayed offers

  • Venue A: 300 shares at $24.98
  • Venue B: 200 shares at $24.99
  • Venue C: 400 shares at $25.00
  • Venue D: 600 shares at $25.01

Under Regulation NMS order-protection, what is the minimum number of shares the desk must route away before filling the rest internally at $25.00?

  • A. 900 shares
  • B. 1,200 shares
  • C. 500 shares
  • D. 300 shares

Best answer: C

Explanation: Only the 300 shares at $24.98 and 200 shares at $24.99 are better-priced protected offers, so 500 shares must be routed before an internal fill at $25.00.

Order protection focuses on avoiding trade-throughs of better-priced protected quotations. Here, the desk must clear the shares offered below $25.00, which total 500 shares, but it does not have to route to the same-priced $25.00 offer just to satisfy Regulation NMS order-protection.

The core concept is the Regulation NMS Order Protection Rule: a desk may not execute at a price inferior to a better-priced protected quotation. Because the firm wants to fill internally at $25.00, it must first access all protected offers priced lower than $25.00.

That calculation is:

  • 300 shares at $24.98
  • 200 shares at $24.99
  • Total = 500 shares

The 400 shares displayed at $25.00 are at the same price as the proposed internal execution, so they are not a trade-through issue for order-protection purposes. The 600 shares at $25.01 are worse-priced and therefore also do not have to be accessed first. The closest trap is treating same-priced liquidity as an order-protection requirement rather than a separate best-execution consideration.

  • Only best offer misses the protected offer at $24.99, so routing just 300 shares would still trade through a better-priced quote.
  • Including same price incorrectly adds the 400 shares at $25.00, which are not better-priced than the proposed internal execution.
  • Sweeping the full order confuses order protection with a duty to route the entire customer order away regardless of price.

Question 5

During a principal’s weekly trade-reporting review, an exception report shows that several NMS equity orders routed by the firm’s smart order router were reported to CAT with the firm’s MPID as the executing venue, even though the router log shows the orders were sent to an ATS and executed there. On the same orders, the CAT route event timestamp is later than the execution event timestamp. Customer price and size are correct, and no complaints have been received.

Which action best aligns with a durable supervisory standard?

  • A. Reconcile the OMS, router, and ATS records; correct the CAT submissions; and test the venue/MPID mapping control
  • B. Ask traders to annotate future order tickets with the ATS name and close the current exceptions
  • C. Leave the CAT records unchanged because the customer executions were accurate
  • D. Wait to investigate unless the ATS or regulator rejects the submissions

Best answer: A

Explanation: Mismatched venue, MPID, and event timing indicate an audit-trail control failure that requires correction and root-cause testing, not just trade-by-trade cleanup.

The issue is not customer execution quality alone; it is the integrity of the firm’s reporting and audit trail. When venue, MPID, and event timestamps do not align with the source records, the principal should reconcile the data, correct the reports, and address the control weakness that caused the mismatch.

This scenario points to a reporting-control breakdown. Accurate price and size do not cure inaccurate CAT data when the executing venue, MPID, and event sequencing are wrong. A principal should compare the firm’s source records across the order management system, router, and execution venue, submit needed corrections, and determine whether a mapping or interface problem caused the mismatch.

Reasonable supervision focuses on both remediation and prevention:

  • verify the true route and execution path from source records
  • correct the affected CAT records
  • identify the root cause in identifier or timestamp logic
  • test and strengthen the control before treating the issue as resolved

The closest distractor is the idea that correct customer fills make the issue immaterial, but audit-trail accuracy is itself a core supervisory obligation.

  • Customer outcome only fails because correct fills do not excuse inaccurate venue, MPID, or timestamp reporting.
  • Manual notes going forward fails because it does not correct the existing records or fix the underlying system mapping problem.
  • Wait for rejection fails because supervision should identify and remediate reporting exceptions proactively, not only after outside notice.

Question 6

A firm’s WSPs require a principal to review unmatched trade comparisons, DK notices, and any changes to institutional block-trade allocations made after execution. Which supervisory obligation does this control primarily support?

  • A. Approval of retail communications before use
  • B. Accurate trade booking, comparison, and supportable account allocation
  • C. Best execution review of venue routing decisions
  • D. Reg SHO supervision of short sale locates

Best answer: B

Explanation: These exceptions test whether executed trades were recorded correctly, compared successfully, and allocated to the proper accounts on a supportable basis.

This control is aimed at post-trade accuracy. Unmatched comparisons, DK notices, and late allocation changes are classic indicators of possible booking errors, compare breaks, or unsupported account allocations that require principal review.

Trade comparison and allocation controls are designed to ensure the firm’s books and records match the executed trade, the counterparty can compare the trade correctly, and block orders are allocated to the proper customer accounts on a timely and supportable basis. Unmatched trades and DK notices signal possible booking or comparison errors, while post-execution allocation changes raise supervisory concerns about accuracy, documentation, and fairness of the allocation process.

  • Verify the executed terms were entered correctly.
  • Resolve compare breaks and document corrections.
  • Review late allocation changes for approval and support.

This is different from controls focused on routing quality, short sale compliance, or communications approval.

  • Best execution relates to routing and execution quality, not whether the booked trade later compares and allocates correctly.
  • Reg SHO addresses short sale locate and close-out supervision, not post-trade comparison breaks or allocation changes.
  • Communications approval governs public-facing materials, not trade records, counterparty comparisons, or block allocations.

Question 7

A general securities principal reviews a T+1 exception memo for a retail equities desk. Most items are routine: several institutional DKs were cured on trade date, and two street-side delivery fails are awaiting corrected depository instructions. One practice is different: when a representative enters the wrong retail account number, operations moves the executed trade to a different customer account after the original confirmation has been sent, and no corrected confirmation is issued if the price and quantity stay the same. What is the primary supervisory red flag?

  • A. Street-side delivery fails caused by incorrect depository instructions
  • B. Routine DK activity that may slow trade comparison
  • C. Manual exception handling that could delay settlement processing
  • D. Post-confirmation reallocations that leave customers with inaccurate final trade disclosures

Best answer: D

Explanation: Changing the customer allocation after a confirmation without issuing a corrected confirmation risks both inaccurate customer disclosure and weakened transaction finality.

The key risk is not the ordinary settlement noise; it is changing who the trade belongs to after the customer has already been sent a confirmation. That creates inaccurate customer records and undermines confidence that the confirmed transaction is final unless the firm issues a proper correction.

The core concept is that standard settlement exceptions, such as DKs cured quickly or delivery problems caused by bad instructions, are usually operational issues that can be resolved within normal post-trade processing. By contrast, reallocating an executed retail trade to a different customer account after the original confirmation has already been sent directly affects the accuracy of customer disclosures and the finality of the transaction record.

A principal should view this as the most serious red flag because the control failure is not just delayed settlement; it is allowing a completed, disclosed trade to be reassigned without sending corrected disclosure to the affected customer. The closest distractors describe normal settlement frictions, but those do not inherently mean the customer received an inaccurate final confirmation.

  • DKs are routine because same-day cured comparison issues are ordinary settlement exceptions, not the clearest disclosure or finality failure here.
  • Delivery fails matter less because wrong depository instructions can delay settlement, but they do not by themselves show that the wrong customer received the trade confirmation.
  • Manual processing is secondary because slower workflow is a weaker concern than changing the customer allocation after disclosure without a corrected confirmation.

Question 8

A principal reviews an exception report showing that a retail customer entered a limit order marked “Route only to Nasdaq; do not internalize.” The firm’s routing disclosure states that non-directed orders may be sent to the firm’s ATS for possible price improvement. The desk instead routed this order to the ATS and executed it there. Which supervisory response best matches these facts?

  • A. Defer escalation unless the customer later complains about the execution.
  • B. Escalate immediately as a customer-instruction exception and review remediation.
  • C. Handle it in the next periodic best-execution committee review only.
  • D. Accept the fill because the firm’s routing disclosure permits ATS internalization.

Best answer: B

Explanation: An explicit customer routing instruction overrides the firm’s default routing disclosure, so the principal must escalate the contrary execution immediately.

A firm’s general order-routing disclosure applies to non-directed orders, not to an order with a specific customer routing instruction. Because the desk executed the order contrary to that instruction, the principal should treat it as an immediate supervisory exception requiring investigation and possible remediation.

The core concept is that specific customer instructions control the handling of that order, even when the firm has disclosed a general routing practice for other orders. Here, the order was clearly marked as customer-directed and specifically prohibited internalization, yet the desk sent it to the firm’s ATS and executed it there. That creates an order-handling conflict that should be escalated promptly as a potential supervisory and conduct issue.

The principal should investigate the cause, preserve the review trail, assess whether other orders were affected, and consider customer remediation and control changes. A periodic best-execution review may later analyze the event, but it does not replace immediate escalation of a clear exception. The key takeaway is that disclosed default practices do not override explicit customer instructions.

  • Disclosure confusion fails because general routing disclosure does not override a direct customer instruction on a specific order.
  • Wait for complaint fails because supervisory escalation is triggered by the exception itself, not by whether the customer notices it.
  • Periodic review only fails because a best-execution committee review is too late for a known order-handling breach.
  • Immediate escalation fits because the decisive fact is the explicit routing instruction that was not followed.

Question 9

An operations manager asks a Series 23 principal which pending settlement item can stay in normal clearance processing instead of being escalated as a special delivery exception. Which item would NOT usually require added principal attention before acceptance?

  • A. Physical certificates delivered in irregular units for the contract
  • B. Book-entry bonds in exact amount through normal clearance
  • C. Delivery against a sight draft instead of regular DVP
  • D. Registered certificates needing assignment and signature review

Best answer: B

Explanation: A routine book-entry delivery in the exact contracted amount through normal clearance is standard good delivery and does not present the special risks raised by irregular units, registered issues, or draft settlement.

Added principal attention is generally warranted when the delivery departs from ordinary good-delivery processing. Irregular units, registered certificates requiring assignment review, and delivery with draft each create extra settlement or transfer risk, while a standard book-entry delivery in the exact amount does not.

The key is whether the delivery presents a special good-delivery or settlement-control issue. Deliveries in irregular units can create rejection, denomination, or re-delivery problems. Registered securities require careful review of assignments, endorsements, and signature guarantees before acceptance because transfer errors can make the delivery defective. Delivery against a draft also changes the normal payment-and-delivery process, so firms typically give it added supervisory attention.

A book-entry bond delivery in the exact contracted amount through ordinary clearance is routine and fits normal settlement controls unless some other exception is present. The fact that the other choices involve nonstandard form, transfer review, or draft mechanics is what makes them escalation items.

  • Irregular units still merit review because nonstandard units of delivery can create good-delivery exceptions even if the total amount matches the trade.
  • Registered certificates need added scrutiny because assignments and signature guarantees must be in proper form before acceptance.
  • Sight draft settlement is not ordinary DVP processing and can introduce timing and collection risk that deserves escalation.

Question 10

A general securities principal is reviewing trade-reporting exceptions under the firm’s WSPs.

Exhibit:

WSP closure standard:
- Close an exception only after the corrected submission is accepted.
- Escalate repeated exceptions for trend review.

Exception summary:
OTC TRF | Late equity report         | Corrected; accepted   | 4th this month
TRACE   | Bond price transposed      | Corrected; accepted   | Isolated
CAT     | Customer acct type omitted | Resubmission pending  | 3rd this week

Which action is most appropriate?

  • A. Escalate only the TRACE item because accuracy errors require special handling.
  • B. Close all items because each has a documented remediation note.
  • C. Reopen the TRACE item because same-day correction cannot satisfy supervision.
  • D. Keep the CAT item open and escalate the CAT and OTC TRF patterns.

Best answer: D

Explanation: The CAT item is still unresolved because resubmission is pending, and both CAT and OTC TRF show repeated exceptions that the WSP requires to be escalated.

The exhibit says exceptions may be closed only after the corrected submission is accepted, so the CAT item remains open because its resubmission is still pending. The WSP also requires escalation of repeated exceptions, which applies to both the CAT pattern and the OTC TRF pattern, while the isolated corrected TRACE item may be closed.

The key supervisory point is that trade-reporting review is not complete when a problem is merely identified or a fix is started. A principal must confirm that a required correction was actually accepted, and must also escalate recurring reporting problems for trend review across venues.

Here, the TRACE item was corrected, accepted, and marked isolated, so it can be closed. The OTC TRF item was corrected and accepted, but it is the 4th similar event this month, so the pattern must be escalated even though that individual report was fixed. The CAT item is more urgent because the correction is not yet accepted; “resubmission pending” means the exception is still open, and it is also the 3rd similar event this week, so it also requires escalation.

A remediation note or vendor ticket alone does not satisfy the WSP closure standard.

  • Close everything fails because a pending CAT resubmission is not an accepted correction.
  • Reopen TRACE fails because the exhibit shows the TRACE correction was accepted and isolated.
  • Escalate only accuracy errors fails because the WSP requires escalation of repeated exceptions regardless of whether the issue was timeliness or completeness.

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Revised on Sunday, May 3, 2026