Trust account reconciliations and AI security: what a trust ledger gives away in ChatGPT or Claude.

A trust ledger lists the clients whose money the practice holds, how much and why. Reconciling it against the bank statement is routine, and a formula that will not balance is the kind of problem staff paste into ChatGPT or Claude to find. The sheet contains every client’s name and matter, their balance, the trust bank account, and free-text notes that often record a health or family circumstance. This page marks each cell that bears on the NSW trust account and audit rules and on privacy, and shows how the same ledger is checked on Ermos inside the practice.

The trust account reconciliation spreadsheet

Prepared at the end of each month by comparing the client ledgers with the trust bank statement, and drawn on by the auditor at year end.

An invented trust ledger. The BSB and account number are placeholders, and the clients and matters are fictional. Hover or tap any highlighted cell for the analysis; the full list is below.

What leaves the practice

1. 1
   Client names

   Several clients who have nothing to do with each other, on one sheet. A single paste discloses all of them, though only one of them needed the check. Privacy Act guide.

2. 2
   Matters and property addresses

   Which client is buying or selling which property. Keeping client information confidential is listed among the rules of conduct in Schedule 2 of the Conveyancers Licensing Regulation, according to the NSW Government’s conveyancers page.

3. 3
   A client’s balance held in trust

   What a client has paid in and the date. NSW guidance says funds held for a person cannot be used for any other purpose, and the balance shows how much a client has set aside. Privacy Act guide.

4. 4
   A balance owing back to a client

   A small amount left after settlement. The practice has to account for the balance, and an item left in the ledger is the sort of detail an auditor asks about.

5. 5
   A health circumstance in a note

   A named client in hospital and a daughter who instructs. Health information is sensitive information under the Privacy Act, and a free-text note column is where it ends up. Patient data guide.

6. 6
   A trust and its trustee

   The name of a family trust and the trustee, with the deposit it has paid. Information about a business structure and a named individual. Privacy Act guide.

7. 7
   The trust bank account and statement balance

   The account the practice holds client money in and what it held on 31 October. NSW guidance says the account must be at an approved authorised deposit-taking institution, and this is the one a fraudster would want to name.

8. 8
   The reconciliation sign-off

   That a named conveyancer reconciled and signed off the ledger on a date. The audit record shows a human did the work. NSW audits cover all records relating to trust money, and the period ends on 30 June each year.

9. 9
   The difference formula

   A subtraction of two cells with no data in it. Spreadsheet files can also carry hidden columns, cell comments and formulas that read other sheets, so a formula is only harmless when the file around it is.

What happens in Frontier Models (ChatGPT, Claude)

• The whole document is transmitted to the provider’s servers. On personal plans the user cannot choose where it is stored or processed, and for the major providers that has generally meant outside Australia, under that country’s legal process. Some business plans offer storage in Australia, but the provider still receives the content.
• On consumer tiers, prompts can be retained and used to train future models.
• The provider’s staff and systems can reach the content under the provider’s own policies.
• Once sent, the practice no longer controls it. Retention and deletion happen on the provider’s terms.

The same document on Ermos

Part of AI data leakage in conveyancing practices.

Common questions