Which Boundaries Stay, Which Go, and How to Tell Them Apart Before the December Mandates Land
Markets and regulations now operate end to end; most securities firms still run operations function by function. The Treasury clearing mandate shows what that costs. Inside one broker-dealer it lands as a clearing agreement in legal, a debit line in finance's reserve computation, allocations in the stock record, a netting question in net capital, an affiliate-scope decision in onboarding and a margin call in treasury. Seven functions are accountable for pieces of it. No role is accountable for the trade.
The transformation industry's answer is to integrate; the regulator's, written into the supervision, risk-management and customer-protection rules, is to segregate. Both are right, about different boundaries. Every boundary in a securities operation is either a control boundary, which a rule or a written risk limit requires and which stays, or a coordination boundary, which a reorganization, a system's edge or a contract left behind and which is where the friction lives. The redesign is the classification, boundary by boundary, done before anything moves; the live test is the industry's request to deliver customer margin on a net omnibus basis.
This report maps one mandate across seven functions of one firm, sets out the eight kinds of boundary a reorganization leaves untouched, states the three-question test and the four dispositions it produces, applies the test to eleven boundaries in trade-to-settle with the rule behind every keeper, defines the six flows and the flow-owner role, and sets the classification against the calendar from December 7, 2026 to October 11, 2027.
Selected Conclusions
• Consultants say integrate and regulators say segregate, and both are right about different boundaries. A control boundary is one a rule or a written risk limit requires, and it stays; a coordination boundary is one a reorganization, a system's edge or a contract left behind, and it is where the friction lives.
• A control survives the move inside a flow only under three tests. An independent performer, evidence the flow itself produces, and a limit set outside the flow; the request to net customer margin across customers asks the Commission to reclassify a control boundary, and the more likely outcome is that it stays.
• Changeability is the interval from rule text to production, and the model sets it. A function-by-function firm spends most of that interval at its own boundaries, which is why 88 percent of surveyed firms could not finalize without more clarity; a flow-owned model builds to the draft and changes the parameter.
Subscribers to the Journal may download the full report, including 7 Conclusions and 20 Recommendations and Action Items.
