Treadstone Associates
Article · Trust accounting

Can AI reconcile a law firm trust account?

The monthly trust comparison is one of the few pieces of professional work whose form is prescribed down to the signature. That makes it an unusually clear test of where automation belongs.

Treadstone Associates · Updated 2026

Key takeaways

  • • In Ontario the monthly comparison must be signed by the licensee who prepared or approved it — a person, not a process.
  • • Ontario requires the record to be created within twenty-five days of month end; British Columbia allows thirty days from the effective date.
  • • Electronic records are expressly permitted in Ontario, but a paper copy must be producible promptly on the Law Society’s request.
  • • AI matches, classifies and drafts the exception narrative. The licensee reviews, corrects and signs.

The short answer

Yes to the arithmetic and the assembly; no to the accountability. A tool can match deposits to receipts, match withdrawals to disbursements, produce the client-by-client listing and draft the explanation for every difference. It cannot be the licensee, and in Ontario the by-law says so in terms: paragraph 8 of section 18 of By-Law 9 requires a record, signed by the licensee who prepared or approved it, showing a comparison made monthly of the total of balances held in the trust account or accounts against the total of all unexpended balances of funds held in trust for clients, together with the reasons for any differences.

That paragraph also names the two supporting records, and they too must be signed: a detailed listing made monthly showing the amount held in trust for each client and identifying each client, and a detailed reconciliation made monthly of each trust bank account. So the deliverable is not one document but three, and each carries a name.

What Ontario actually asks for

  • • The comparison itself — trust bank balances against client trust ledger balances, with reasons for differences.
  • • A monthly client listing — how much is held for each client, each client identified.
  • • A monthly detailed reconciliation of each trust bank account.
  • • A signature from the licensee who prepared or approved each of them.

Timing is prescribed too. Section 22 requires the financial records to be entered and posted so as to be current at all times, with an exception in subsection 22(2): the paragraph 8 record must be created within twenty-five days after the last day of the month to which it relates. Retention runs long — section 23 requires records under sections 18, 19 and 19.1 to be kept for at least the six-year period preceding the licensee’s most recent fiscal year end, and the records under paragraphs 1, 2, 3, 8, 9, 10 and 11 of section 18, which include the comparison, for at least ten years.

Section 21 is the provision that makes automation lawful and also constrains it. Subsection 21(1) permits the records to be entered and posted by hand or by mechanical or electronic means; subsection 21(2) requires that where a record is entered and posted electronically, the licensee ensure a paper copy can be produced promptly on the Society’s request. Any tool you cannot export a complete, readable copy from fails that test on the day it matters.

British Columbia is close but not identical

If you practise in more than one province, do not assume one calendar. Under Rule 3-73 of the Law Society of British Columbia’s Rules, a lawyer must prepare a monthly trust reconciliation of the total of all unexpended balances held for clients as they appear in the trust ledgers against the total of balances held in the trust bank accounts, together with the reasons for any differences. Subrule 3-73(2) lists the supporting records, subrule 3-73(3) requires each reconciliation to include the date on which it was prepared, subrule 3-73(4) requires the reconciliation and its supporting listings to be retained for at least ten years, and subrule 3-73(5) requires it to be made not more than thirty days after the effective date of the reconciliation.

BC also fixes what happens when the comparison fails. Rule 3-74 requires a lawyer who discovers a trust shortage to pay in enough funds immediately to eliminate it, and to make an immediate written report to the Executive Director where the shortage is greater than $2,500 — expressly including shortages caused by service charges, credit card discounts and bank errors. That last clause matters for automation: a shortage created by a bank fee is still a shortage, and a system that quietly absorbs small differences is hiding a reportable event.

In Alberta the same duty runs through the Law Society of Alberta, which operates the Trust Safety programme for responsible lawyers and firms; in Quebec it is the Barreau du Québec. Read your own regulator’s rule rather than a summary of someone else’s.

So what should AI actually do

  • • Match and classify. Bank line to receipt, bank line to disbursement, with a confidence flag and the reason for every unmatched item.
  • • Age the exceptions. Stale outstanding cheques and long-dormant client balances are the two findings that generate work, and both are trivially detectable.
  • • Draft the difference narrative. The by-law wants reasons for differences. Drafting those in plain sentences is exactly what a language model is for.
  • • Assemble the pack. Comparison, client listing, bank reconciliation, in the order a reviewer reads them, with the source documents attached.

And the things it must not do: propose or execute a transfer between trust and general. Rule 3.6-10 of the Rules of Professional Conduct provides that a lawyer must not appropriate client funds held in trust for or on account of fees except as permitted by the by-laws, so that movement is a licensee’s decision every time, however obvious the arithmetic looks. Treadstone Law’s article on trust accounts when buying a law practice is a reminder of how carefully trust balances are treated when a practice changes hands, and a related answer shows why third parties are trained to verify trust details independently.

Worked example (illustrative)

A six-lawyer Ontario firm has been producing the monthly comparison in the last week before the deadline, from a spreadsheet rebuilt each time. It moves to a matching step that runs nightly against the bank feed and the trust ledger, with three queues: matched, probable, unmatched.

The change is not that the comparison takes less time. It is that by the fifth of the month the unmatched queue holds four items instead of forty, and the bookkeeper spends the time on those four. The signing licensee still reads the pack and still signs it, but signs something that has been stable for three weeks rather than assembled the night before.

The measures worth recording are the number of open unmatched items at day five, and the number of months in which the paragraph 8 record was created inside the twenty-five-day window without an evening spent on it. Both are countable from records you already keep.

Questions we get asked

Can the tool sign on the licensee’s behalf?
No. The by-law wants the signature of the licensee who prepared or approved the record. An approval action recorded under a named licensee’s credentials, on a pack that licensee has actually read, is the shape of the control; a scheduled job is not.

Can we keep everything in the cloud?
Section 21 permits electronic records, and requires that a paper copy be producible promptly on request. Test that export before you migrate, not after.

What if the difference is small?
Then it is a small difference with a reason, and the reason goes in the record. In British Columbia, a shortage above the reporting threshold must be reported immediately in writing, and bank errors and service charges are expressly included.

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