Trace confidential deal information through organisational separation, named wall crossing and restricted-list controls, with precise UK and US scope.
Information barrier and wall crossing
An information barrier is an organisational arrangement that controls who may receive or use confidential information across parts of a financial firm. Wall crossing is a controlled disclosure to a person who would ordinarily remain outside that information. For a quant, the consequence is immediate: a dataset being technically accessible does not make it an authorised research input, and learning confidential deal information can restrict trading and publication.
The barrier is the control mechanism; material nonpublic information (MNPI) is one type of information it protects. Confidential information is broader than MNPI: client identities or commercially sensitive work can require protection without satisfying the relevant legal test for inside information. Morgan Stanley’s 2026 Code of Conduct makes this distinction and limits access and sharing to authorised, need-to-know purposes. That is a concrete firm policy example, rather than a definition of every jurisdiction’s law. Morgan Stanley, “Protecting Confidential and Sensitive Information”.
Follow the information, not the department name
Consider a fictional firm advising Lumen on an unannounced transaction. Its deal team receives confidential projections and transaction terms. Research analysts Aya and Ben use public information; Trading operates in the market. Ordinary channels must not deliver the deal material to Research or Trading.
The separation has to survive the actual workflow. A restricted deal folder accomplishes little if its contents are copied into a shared notebook, exported to an unrestricted table or discussed in a group chat. In this example, access controls follow the information through storage, communication and derived work. A valuation output can itself reveal confidential assumptions, even when the original spreadsheet is absent.
Fictional Lumen workflow: deal information is blocked from ordinary Research and Trading access. A controlled exception names Aya alone, records purpose, approval, consent and restrictions, and leads to a later status review. Ben and Trading remain outside the information; removing Aya’s file access does not erase her knowledge.
Original fictional access-control flow. The three business roles illustrate separation; they do not prescribe a mandatory team structure. Aya’s wall crossing permits scoped receipt of information and adds restrictions; it does not authorise trading.
Several controls can work together: need-to-know permissions, restricted communication channels, physical separation where appropriate, documented responsibilities, and monitoring of whether the separation actually works. This is an architectural description, not a universal checklist. The FCA’s current SYSC 10.2.2 rule defines an information-withholding or non-use arrangement between business areas and says maintaining it includes reasonable steps to keep it effective and adequately monitored. Its permission to withhold information has a specified regulated/ancillary-activity scope and does not override information-transmission requirements arising outside COBS. FCA Handbook, SYSC 10.2.
Crossing the wall changes Aya’s position
Suppose the firm needs Aya’s specialist valuation expertise for the transaction. In this fictional workflow, an authorised control function first establishes the business purpose, records the proposed recipient and information scope, obtains Aya’s agreement to the restrictions, and approves the disclosure. Aya then receives only the agreed material. Ben does not acquire access merely because he sits in the same research group.
The record connects what was disclosed, to whom, when, for what purpose, and with which restrictions. Here, Aya cannot trade the example issuer, pass the information onward, or publish affected public research pending review. Her affected ordinary work must be reassigned or constrained. The control function is a responsibility in this example; it need not be a department bearing a particular name.
An internal specialist consultation and an external market sounding are different situations. In the UK market-sounding context, the FCA has specifically warned about email recipient lists expanding after a gatekeeper has consented, exposing people who have not been wall crossed. Its Market Watch 83 also explains that the UK MAR Article 11 safe harbour concerns qualifying disclosure and depends on its conditions and scope. Consent to receive a sounding does not turn it into permission to trade. FCA, Market Watch 83, “Risk of unlawfully disclosing inside information during a market sounding” and “Multiple brokers market sounding for a transaction”.
A recipient record and a restricted list answer different questions
A wall-crossing record identifies people who received information. A restricted list identifies issuers or instruments and the activities or accounts subject to restrictions. It is not simply a list of employees who have crossed the wall.
The distinction matters to implementation. “Aya received Lumen’s projections” is a recipient fact. “These Lumen-related transactions are blocked for these accounts or business areas” is a restriction rule. A system needs the connection between them without broadcasting the confidential deal rationale to everyone who checks an order.
Scope varies. Morgan Stanley’s 2026 code describes restrictions that can affect employee trading, principal trading, client solicitation and research distribution, with separate lists for some businesses. A restriction may therefore apply beyond the wall-crossed individual, and an issuer can appear on a list for reasons other than that individual’s disclosure. These are examples of that firm’s arrangements, not uniform rules for all firms. Morgan Stanley, “Information Barriers”.
What an effective barrier does—and does not—establish
Protecting information and protecting research independence are connected but different objectives. For US FINRA members within Rule 2241’s equity-research scope, paragraph (b)(2)(G) requires information barriers or other safeguards designed to insulate analysts from potentially biased review, pressure or oversight, including from investment banking and sales and trading personnel. Related provisions address supervision, compensation and research review. A locked folder alone does not resolve those influences; the rule also contains definitions and exemptions that matter to its application. FINRA Rule 2241.
Nor is “we have a wall” a blanket defence to insider trading. Under US Rule 10b5-1(c)(2), a person other than a natural person may demonstrate that a trade was not on the basis of MNPI through the specified conditions: the investment decision-maker was unaware of it, and reasonable policies and procedures were implemented to prevent prohibited trading. Merely naming a barrier establishes neither condition. This provision addresses that particular legal question, not every duty, conflict or trading restriction. 17 CFR 240.10b5-1(a), (b) and (c)(2).
Finally, ending Aya’s access does not erase what she knows. A transaction announcement may leave other confidential details undisclosed. In the example, the control function reassesses the information and remaining restrictions, records the decision, and communicates any release. A missing restricted-list entry or a revoked folder permission cannot substitute for that assessment.
FCA, Market Watch 83. Published 8 September 2025; page updated 22 October 2026. Supervisory observations concerning corporate finance firms, including UK market soundings and barrier effectiveness.
Morgan Stanley, Code of Conduct 2026. “Confidential Information”, “Material Non-Public Information” and “Information Barriers”; an actual firm-policy example.
