Collects, labels, and packages audit evidence on request.
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CASTELLAN
Customer story
Castellan Financial takes 3 days out of the close and finds $283K a year in duplicate payments
An asset manager with 4,200 employees and 9 legal entities deployed the Audit, Controls, and Close Agents ahead of its year-end audit.
“The auditors asked for the lineage record on the first package and never asked again. We went through interim fieldwork without pulling anyone off the close.”
Marcus Lindqvist
Corporate Controller, Castellan Financial
Challenge
Castellan Financial closes 9 legal entities in 3 currencies. In 2025 the consolidated close took 10 business days, and the controller's team tracked 214 tasks in a shared spreadsheet that was accurate only on the afternoon someone updated it. Intercompany differences surfaced late because the entities closed on different days, and the people downstream found out by asking.
The external audit generated 460 prepared-by-client requests plus SOX 404 control testing samples. Three senior accountants spent most of the first quarter locating journal entries, invoices, approvals, and bank statements, naming files, and uploading them, while also trying to close January and February. Auditor follow-ups averaged 1.4 per request because evidence arrived without context.
Accounts payable processed about 7,000 invoices a month across the entities. The ERP's duplicate check matched on exact vendor and invoice number. Internal audit suspected leakage but had only sampled 60 invoices a quarter and found nothing conclusive.
Approach
Read-only first. Castellan connected the ERP general ledger and subledgers, document management, banking, and the email archive through read-only connections. No agent received write access to a financial system at any point in the deployment.
Audit Agent, dry run on last year. Before the current audit began, the team loaded the prior year's PBC list and had the agent assemble packages for 80 requests. The controller and the engagement senior compared them to what had been submitted manually. The agent's packages had complete lineage records and consistent naming; two manual packages from the prior year had been missing an approval that the agent found in the email archive.
Controls Agent, six tests. Internal audit enabled duplicate invoice detection with fuzzy matching, three-way match exceptions, vendor bank-detail changes without callback, split purchases under approval thresholds, preparer-approver conflicts on journal entries, and expense policy checks. Thresholds were set per entity. Every exception required disposition by AP or controllership.
Close Agent, the real checklist. The 214-task spreadsheet became the agent's dependency graph. Bank and subledger reconciliations that tied were prepared with support attached. Recurring accruals were drafted from prior periods and open purchase orders. Late tasks were nudged, then escalated to the controller after 4 hours. Preparer and reviewer separation was enforced on every task.
Results
The close went from 10 business days to 7 by the second cycle. Most of the gain came from removing waiting: downstream owners saw upstream blockers in real time, and 61 of the 214 tasks were prepared before their owners arrived in the morning. Reconciliations with unexplained differences were never closed automatically; there were 14 of them in the first cycle and 6 in the third.
The Controls Agent identified duplicate payments annualizing to about $283,000 in its first 90 days, most of them invoices resubmitted under a second vendor record or with a suffix appended to the invoice number. AP recovered the majority from vendors. False positives fell by half after the first month of dispositions.
Across the audit year, the finance team recorded about 900 hours saved on evidence collection. Auditor follow-ups fell roughly 70% because packages carried an index, lineage, and the selection method. The three senior accountants worked on the close during fieldwork for the first time.
| Measure | Result1 |
|---|---|
| consolidated close, down from 10 | 7 days |
| annualized duplicate payments identified in 90 days | $283K |
| saved on audit evidence in the first year | ~900 hrs |
| auditor follow-up requests | −70% |
Timeline
22 weeks from scoping to steady state, in 5 phases.
Phase 1: Weeks 1-2
Connect and scope
Read-only connections to ERP, document management, banking, and email archive. Audit scope, entities, and periods defined.
Phase 2: Weeks 3-4
Audit Agent dry run
80 prior-year PBC requests assembled and compared with the engagement team.
Phase 3: Weeks 4-6
Controls Agent live
Six tests enabled per entity. AP and controllership disposition workflow in place.
Phase 4: Weeks 6-9
Close Agent, first cycle
214-task checklist imported with dependencies. Shadow prep for one cycle, live the next.
Phase 5: Weeks 10-22
Year-end audit
460 PBC requests handled through the Audit Agent with controller release on every package.
- 1.Modeled outcomes from design-partner deployments. Results vary by data quality, workflow scope, and approval policy. ↩
Agents in this story
The agents Castellan Financial runs
Each agent is scoped to one workflow, reads only permitted data, logs every action, and routes consequential actions to a named approver.
Tests each transaction for duplicates, anomalies, and policy breaches.
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Runs the month-end checklist. Chases what is late. Records who signed.
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Start with the workflow that pays back first
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