Which month-end close task should a controller test AI on first?

The close is a calendar of small jobs that lean on one another. The University of Washington publishes its own eight-business-day version: receiving must be complete on the month's last day, the receipt accrual runs on day one, reversing journals post on day two, journals must be approved by 2 p.m. on day six, with any still in process at 5 p.m. cancelled, and days seven and eight belong to the controller's office alone. Most of what a controller would hand to AI sits in the first days, when time is shortest.

A first test needs four things: finished examples from closed months, an answer key that doesn't depend on anyone's memory, a reviewer who does the task today, and inputs that are documents or exports, not conversations. Held against those, the candidates sort quickly:

• Accruals from open POs and receipts: strong on all four.
• Card and bank reconciliations: a clean key, though much of the bank matching may already be done by your system.
• Journal entry support: good for standard recurring entries, poor for the rest.
• Intercompany: the answer key lives in two sets of books.
• Flux explanations: the numbers are easy to check, the reasons are not.

FASB's conceptual framework defines accrual as recognizing an asset or liability, with the related revenue or expense, for an amount expected to be received or paid in the future, usually in cash; its first examples are purchases and sales of goods or services on account. The accrual for goods and services received but not yet billed is exactly that, and its inputs are documents: the open PO report, the receiving log, invoices dated in the month that arrive after it, and emails confirming work was done.

It comes with two answer keys: the entry your team booked, and the invoices received after cutoff, which show what was really owed (the check auditors call a search for unrecorded liabilities). A draft that matches the first and is borne out by the second has passed.

Your reviewer, the person who books the accrual today, will watch where it breaks: a receipt valued at the PO price when the invoice came in higher, a partial receipt accrued in full, a service PO with no receipt because nobody receives services, an invoice already entered in AP and accrued a second time, and freight or tax that sits on no PO line. If your ERP already runs a receipt accrual, the test is about everything that report can't see.

What stays out: accruals that rest on estimates rather than documents, such as bonuses, legal costs, warranty reserves and taxes. Those are judgment calls, and the people who own them keep them.

Reconciliations have the plainest answer key in the close: a signed reconciliation that ties, with a short list of reconciling items. California's State Administrative Manual, section 7901 (revised June 2021), shows how firm the form can be: agencies reconcile balances to supporting documents and to outside records such as bank statements monthly, within 30 days; every reconciliation shows the preparer's and reviewer's names, signatures and dates; and reconciling differences must be resolved before financial reports are prepared.

A close guide from the Justice Department's Office of Justice Programs support center for grantees in the U.S. territories, laid out by timeframe from AICPA closing-cycle practices, puts preliminary bank reconciliations the day before period end, because cash is the asset most likely to be involved in fraud or misuse. The catch for a test is that bank feeds and matching rules may already clear most lines. If so, test the leftovers: unmatched deposits, fees, a transfer that cleared in the next month.

Card reconciliations may be the better pick of the two, because every line has a document behind it. The federal statute on government purchase cards, 41 U.S.C. 1909, sets a pattern worth borrowing: each cardholder is assigned an approving official other than the cardholder, and each statement is reconciled against receipts and other supporting documents. A draft can match each charge to its receipt, propose the GL code your team used last time and list every charge with no receipt. The cardholder and the approver still sign, and any write-off stays with them.

Pulling the support for each entry (the schedule, the invoice, the approval email) is steady document work, and closed months are full of finished examples. The PCAOB's auditing standard on fraud, AS 2401, separates standard entries, used every month for sales, purchases, cash disbursements and recurring estimates and generally covered by the company's controls, from nonstandard ones, such as a business combination or an impairment, which may not get the same level of control.

The same standard tells auditors which entries to look at hardest: those posted to unrelated, unusual or seldom-used accounts, made by people who don't usually make entries, recorded at period end or after closing with little or no explanation, or carrying round numbers, and those in accounts with significant estimates, unreconciled differences or intercompany transactions. A first test belongs at the other end: standard recurring entries, where your reviewer can say exactly what complete support looks like.

The OJP close guide adds a check worth building in: confirm each recurring entry is still right for this month, since a change such as an employee leaving can make a fixed payroll entry wrong. Top-side, post-closing and nonstandard entries stay with your team.

Intercompany looks like a reconciliation, but its answer key sits in two ledgers kept by two teams, often on two systems after an acquisition. When the entities disagree, someone decides which side is right, and that decision is rarely written down where a test could read it.

In its audit of the U.S. government's consolidated financial statements for fiscal years 2025 and 2024, released on March 19, 2026, GAO listed the government's inability to adequately account for intragovernmental activity and balances between federal entities among the three major impediments that kept it from issuing an opinion. Inside one company the stakes are smaller, but the shape is the same: two sides, two timings, and a difference nobody owns until someone is assigned to it.

Test it later, with exports from both entities for the same closed months and the elimination entries your team booked, after a simpler task has passed.

Working out what moved is arithmetic. Explaining why takes facts from outside the ledger: a price increase, a lost customer, an invoice booked in the wrong month. The SEC's rule for MD&A in public filings, Regulation S-K Item 303, shows what a good explanation does. Where line items change materially from period to period, including where changes inside one line item offset each other, it asks for the underlying reasons in quantitative and qualitative terms, and for how much of a change in sales came from price, from volume and from new products.

A private company's flux memo answers to no such rule, but the bar is a good one, and it is why flux makes a weak first test: past memos give an answer key for the numbers, not the reasons, and two careful people can explain one variance differently. A draft can do the groundwork: which accounts moved past the threshold your controller sets, which vendors, customers or entries drove each move, and which offsetting changes hide inside a single line. The words that go to the owner or the board stay with the controller.

Pick two or three closed months and pull 20 to 30 receipts and open PO lines from them, each paired with the accrual line it became and the invoice that followed. Put the awkward ones in on purpose: a partial receipt, a service PO, a price change, an invoice that was already in AP. Copies and exports go over only after the NDA is signed; nothing logs in to your ERP, and nothing is posted.

Before anything runs, the owner names the reviewer, and the success criteria go in writing: every receipt either accrued or marked with a reason, nothing accrued twice, every line traced to its source, and anything the draft can't settle handed to a person. You also get a price range for running the task live.

Your reviewer sets each draft beside the booked entry and the later invoices, and decides. After a yes, the task runs live for about 30 days, through one real month-end, with a person approving every accrual line before it posts. None of this is accounting advice: the drafts follow the treatment your team already uses, and questions of treatment belong to your team and your auditors.