Order prioritisation and matching in an alternative liquidity pool

An ALP is a trading venue where orders can interact outside the conventional exchange order book. The operating rules matter because apparently small design choices—time priority, price priority, order types, or simultaneous routing—can change the chance and sequence of execution. The SFC expects ALP Guidelines to give users clear information about how the pool operates.

Explain the order path

The guidelines should describe the order posting feature and what happens after an order reaches the pool. For example, an operator may allow an order to be routed to an exchange while remaining available in the ALP. Users should be told whether this is possible, how the order is prioritised, and what controls or opt-out choices exist when a third-party ALP is involved.

Why priority information matters

If an order is displayed in more than one place, its relative priority may change when another venue executes first or when the order is modified. A user deciding whether to submit, route, or cancel an order needs to understand those consequences. The operator should not leave material matching mechanics hidden in technical documentation that users cannot practically find or understand.

Third-party routing and user choice

Where an ALP routes orders to a third-party pool, the SFC has highlighted the need to disclose that routing and explain any opt-out options. Users should also be directed to relevant third-party guidelines so they can understand how the external venue handles orders. This is a transparency and informed-choice issue; it does not mean every ALP must use the same matching algorithm.

Exam-ready checklist

• What order types and posting options are available?
• How are orders prioritised and matched?
• Can the same order be sent to an exchange and an ALP?
• Does routing to a third party occur, and can users opt out?
• Could order modification or cancellation change queue priority?
• Are the relevant guidelines provided to users before they trade?

Describe the matching logic in plain language

An ALP guideline should tell a user what happens after an order is entered: whether it is visible to other participants, whether the pool matches at a midpoint or another price, how orders are ranked, and what happens when orders arrive at the same price. If the system uses time priority, pro-rata allocation or another method, explain the rule and any exceptions clearly enough for a user to anticipate how an order competes.

Disclose how amendments affect priority. A price change may cause an order to lose its queue position, while a quantity change can be treated differently under the pool’s rules. State whether an order can rest, expire, be rejected or be partially filled, and explain how the user receives execution information.

Explain routing and interaction with other venues

If the operator sends an order to an exchange or another liquidity pool while it remains active in the ALP, describe the order sequence, cancellation mechanics and safeguards against duplicate execution. Clarify whether a fill at one venue automatically cancels the other order, how quickly that cancellation is sent, and what happens if the venue is disconnected.

A user needs to know whether the order can interact with external participants, whether the destination is an affiliate or third party, and whether the ALP operator receives fees or other benefits from the route. If a third-party ALP is involved, disclose the relevant guidelines and any available opt-out choice as the SFC has highlighted.

Make conflicts and execution quality visible

The operator should explain any feature that could affect execution priority or create an incentive for the operator, an affiliate or a participant. Examples include proprietary orders, sponsored access, internalisation, queue-jumping mechanisms, discretionary matching or routing rebates. The document should be accurate about the system’s actual behavior, not simply state that all orders are treated fairly.

Controls can include documented priority rules, surveillance for misuse, testing of the matching engine, access segregation and review of complaints or unusual fills. Keep records that allow the firm to reconstruct order entry, amendments, routing, matching and execution timestamps.

A practical user disclosure checklist

Before launch or a material change, test the guidelines from a user’s perspective: Can the user understand order types, priorities, routing, fees, execution reports, cancellation behavior and outage handling? Are limitations prominent? Is the third-party arrangement accurately named? Are choices and consent captured?

For an exam response, focus on transparent mechanics and informed choice. The SFC does not prescribe one universal ALP matching algorithm; the operator must explain and control the algorithm it actually uses.

Work through an order example

Assume a client enters a limit order in an ALP and the operator also routes the order to an exchange. The guideline should tell the client whether both orders are live at once, whether an exchange fill cancels the ALP order automatically, and how the operator prevents a second execution during the cancellation delay. It should also say how a partial fill changes the remaining quantity and whether that remaining amount keeps its original priority.

If a client amends the limit price, explain whether the order loses time priority and re-enters the queue. If a venue is disconnected, disclose whether orders are cancelled, held or rerouted and how clients are notified. These mechanics affect execution outcome and belong in understandable user documentation.

Governance and testing of the pool

The operator should maintain a controlled specification of matching logic and test changes before release. Test cases should cover simultaneous orders, partial matches, stale prices, duplicate messages, rejected routes, cancel/replace races and recovery after a connection failure. A release should be approved by personnel with appropriate authority and should retain a rollback plan.

Surveillance should look for repeated priority advantages, unexplained execution disparities, misuse of confidential order information and deviations from published rules. Complaints and execution-quality reviews can identify where the written explanation is incomplete or the system is behaving differently from the documented method.

Key takeaway

ALP Guidelines should explain how orders travel and compete for execution. Focus on disclosure of posting, routing, prioritisation, matching, and user choice rather than assuming all pools work alike.