T4 Slip Season: AI Year-End Payroll Prep for Burnaby

T4 season is closer than it looks

It's late October. Payroll feels routine right now. Then January arrives and someone notices that two people have old addresses on file, one SIN is missing, and nobody remembers whether the summer student ever got a group life benefit.

For small teams in Burnaby and across Metro Vancouver, T4 prep usually falls on one person who's also doing five other jobs. This post covers what the CRA actually requires, where AI can save real time on the prep work, and where it shouldn't touch anything.

The rules you're working against

Start with the dates. The CRA says the filing due date for T4 returns is "the last day of February after the preceding calendar year." If that day is a Saturday, a Sunday or a public holiday the CRA recognizes, you have until the next business day (CRA, When to file information returns). February 28, 2027 falls on a Sunday, so under that rule your 2026 slips are due Monday, March 1, 2027.

Employees need their slips by the last day of February too. The CRA's employer guide says it "may charge you a penalty of $25 per day for each T4 slip that is not given to an employee" (CRA, RC4120 Employers' Guide). If you want to email slips, the same guide says you need written consent from each employee first. A portal has to be secure, and anyone who asks for paper gets paper.

How you file matters as well. For returns filed on or after January 1, 2024, you must file electronically once you have more than 5 slips of the same type in a calendar year (CRA, How to file information returns). Filing on paper anyway costs $125 for 6 to 50 slips, and the penalty goes up from there. CRA Web Forms handle up to 100 slips. Internet file transfer takes XML files up to 150 MB from payroll software.

Late filing is the other risk. Under the CRA's administrative policy, 1 to 5 late slips cost a flat $100. For 6 to 10 slips it's $5 per day to a maximum of $500, and for 11 to 50 it's $10 per day to a maximum of $1,000 (CRA when to file page, last modified July 3, 2025). That won't sink a 15 person company, but you can avoid it entirely.

Where AI actually helps

Filing usually isn't the slow part. Cleaning up the data beforehand is. That's where an AI assistant, set up carefully, earns its place. Here are the jobs we'd give it:

• Data hygiene sweeps. Flag missing SINs, mismatched addresses and people who stopped appearing on pay runs but were never marked as terminated. Missing SINs are worth chasing early. The CRA says you still have to file the slip before the due date even if you don't have the employee's SIN (CRA, T4 slip information for employers).
• Reconciliation prep. Compare deduction totals in your draft summary against your remittance records and list any gaps before you reach the balancing lines (82 to 86) on the T4 Summary. The assistant points out the differences. A person decides what caused each one.
• Benefit reminders. Draft check-in messages to managers about benefits that affect slips. One example: the CRA says you always have to issue a T4 when there's group term life insurance, even if total pay for the year was $500 or less.
• Consent tracking. Find out who hasn't given written consent for email delivery, and send polite reminders in December, not February.
• February questions. Answer "where's my T4?" and "how do I log in to the portal?" from an approved FAQ. Anything about amounts goes straight to a person.

The design rule is simple. The AI flags things and people decide. Your payroll software or your accountant still produces the actual slips and the XML file.

Keep employee data under control

Payroll data is some of the most sensitive information a business holds. In BC, the Personal Information Protection Act defines employee personal information as information collected, used or disclosed "for the purposes reasonably required to establish, manage or terminate an employment relationship." Section 34 says organizations must protect personal information by "making reasonable security arrangements to prevent unauthorized access, collection, use, disclosure" and similar risks (BC Laws, Personal Information Protection Act).

The federal Privacy Commissioner's principles for generative AI are more specific. They say to "use anonymized or de-identified information within prompts" where possible and reasonable, that prompts generally shouldn't be retained or used for secondary purposes, and that "accountability for decisions rests with the organization, and not with any kind of automated system" (OPC, Principles for responsible, trustworthy and privacy-protective generative AI technologies).

In practice that means:

Don't paste a payroll register into a free consumer chatbot. Mask SINs before any record reaches a model. Use a business account and read the vendor's current data retention and training terms yourself, because those terms change. And keep a log of what the assistant flagged and who signed off.

If you'd like a framework for this, the NIST AI Risk Management Framework (version 1.0, released January 26, 2023, plus a generative AI profile, NIST AI 600-1, released July 26, 2024) groups the work into Govern, Map, Measure and Manage. For a small business that comes down to three questions. What is the AI allowed to do? Who reviews its output? How would you know if it got something wrong?

An illustrative run

This is an illustrative example, not a client story. Picture a 25 person trades company in New Westminster. Starting in November, an assistant runs a weekly check against the payroll export and sends the office manager a short list: two addresses that don't match recent pay stubs, one missing SIN, and three people who haven't replied about email delivery. In January it lines up summary totals against remittance records and points out a gap of a few hundred dollars from a corrected pay run. The office manager and the bookkeeper fix it in payroll. Filing happens in mid February with nothing left to chase.

Nothing clever happened there. The useful part is that problems came up in November and not on February 27.

Where this doesn't apply

We'd rather you hear the limits from us.

Very small teams. If you issue 5 or fewer slips, paper filing is still allowed and the data is small. A checklist and an hour with your bookkeeper will beat any setup project.

Payroll providers that already validate. Many payroll services run their own year-end checks. Adding a second layer that disagrees with the first can create confusion instead of removing it.

It isn't tax advice. Generative models can be confidently wrong. The OPC principles specifically ask organizations to take reasonable steps to make sure outputs are accurate. Classifying benefits and unusual payments is a job for your accountant, not a chatbot.

Messy processes stay messy. AI can show you that onboarding never collects SINs on day one. It can't fix your onboarding for you.

Expect modest gains. Statistics Canada found that 12.2% of businesses used AI to produce goods or deliver services in the 12 months before Q2 2025, up from 6.1% a year earlier. Among those businesses, 89.4% reported no change in employment, and 47.2% said AI reduced employee tasks "to a small extent" (Statistics Canada, Analysis on artificial intelligence use by businesses in Canada, second quarter of 2025). That fits what we'd expect here: fewer tedious hours, not a smaller team.

Timing. Starting in late February is too late. Setting this up, testing it on last year's data and getting sign-off takes a few weeks, so November is the right time to start.

Sources

• Canada Revenue Agency, "When to file information returns," 2025. https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/payroll/file-information-returns-slip-summaries/when-to-file.html
• Canada Revenue Agency, "How to file information returns," 2025. https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/payroll/file-information-returns-slip-summaries/how-to-file.html
• Canada Revenue Agency, "RC4120 Employers' Guide: Filing the T4 Slip and Summary," 2025 edition. https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/rc4120/employers-guide-filing-t4-slip-summary.html
• Canada Revenue Agency, "T4 slip: Information for employers." https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/payroll/completing-filing-information-returns/t4-information-employers/t4-slip.html
• Office of the Privacy Commissioner of Canada, "Principles for responsible, trustworthy and privacy-protective generative AI technologies," 2023. https://www.priv.gc.ca/en/privacy-topics/technology/artificial-intelligence/gd_principles_ai/
• Province of British Columbia, "Personal Information Protection Act," SBC 2003, c. 63. https://www.bclaws.gov.bc.ca/civix/document/id/complete/statreg/03063_01
• National Institute of Standards and Technology, "AI Risk Management Framework," 2023 (Generative AI Profile, 2024). https://www.nist.gov/itl/ai-risk-management-framework
• Statistics Canada, "Analysis on artificial intelligence use by businesses in Canada, second quarter of 2025," 2025. https://www150.statcan.gc.ca/n1/pub/11-621-m/11-621-m2025008-eng.htm

Want T4 season to be quieter this year? Book a free call with Autana Solutions. We'll look at your payroll workflow, tell you plainly whether AI is worth it for your team, and if it is, help you set it up before the rush.