Guides · Accountants

Accountants and tax advisers: using AI with payroll, tax returns and statements

Gonzalo Sabater, lawyer · 28 October 2026 · 5 minutes

An accounting practice handles its clients’ most sensitive data every day: tax IDs, bank accounts, payslips, income and assets. AI can save hours explaining a tax notice, reviewing a lease or drafting a reply. But those documents shouldn’t leave the office as they are.

This article is general information, not legal advice for a specific case.

What’s at stake

• Data protection: the practice processes personal data about clients and third parties (employees, tenants, heirs). Where the GDPR applies, it must process only what is necessary and have a processor contract with any external provider.
• Professional confidentiality: accountancy and tax bodies generally require members to keep client information confidential, and engagement letters usually say so too.

What the AI doesn’t need

To explain a notice or review a clause, the AI needs the technical content, not the client’s name, tax ID, account or address.

1. Replace identifiers: names, tax and ID numbers, IBAN and account numbers, addresses, reference numbers.
2. In spreadsheets, watch whole columns of personal data and sheet names.
3. Check what you can’t see: comments, document author, file properties.
4. Review the result before sending it.

Where Maskwise helps

Maskwise validates check digits for ID and tax numbers in five countries, detects IBANs and addresses, and keeps Excel formulas intact when it replaces values with tags. It also reviews comments, sheets, charts and file properties, and checks every copy before you use it, all on your Mac.