Why this matters
When your business pays a subcontractor more than $500 in a calendar year for services, the CRA requires a T4A slip. Preparing these accurately depends on having the right details for each subcontractor — including a Business Number or, for individuals, a Social Insurance Number (SIN).
The safest way to handle a SIN is to keep it in one secure system and nowhere else. Here's the method we recommend.
The secure method we recommend
Collect the details by phone, directly from the subcontractor. Enter them straight into QuickBooks on the supplier record, while you're on the call. Never write the SIN down on paper, in a spreadsheet, in a text, or in an email.
QuickBooks stores the number in a protected field and masks it after saving — the supplier view shows only the last few digits. The result: one secure system of record, no loose copies to protect, and nothing sitting in an inbox. We only access the SIN once a year, when we prepare your slips.
"Straight onto the QuickBooks supplier record — while you're on the call — is the safest home for a SIN."
What to collect from each subcontractor
Full legal name and business name, plus mailing address, always. Incorporation status decides which number you ask for next. If the subcontractor is incorporated, request a Business Number (BN). If they are an individual or sole proprietor, request a Social Insurance Number (SIN). If they charge GST/HST on their invoices, capture their GST/HST number too.
How to record it in QuickBooks
In the Suppliers area, open (or create) the subcontractor and mark them to Track for T4A. Open the supplier profile and select Edit. Set the Supplier Type — Individual for a SIN, or Business for a Business Number. Enter the SIN or Business ID number in the field provided.
Add a short dated note on the record — e.g. "SIN collected by phone [date] for T4A reporting; consent given." Select Save. From here, QuickBooks masks the number.
Getting it right
Read it back. Confirm all nine digits of a SIN out loud before saving — one wrong digit means a rejected slip. The dated note in QuickBooks confirms the subcontractor agreed and knew it was for T4A reporting — no separate paperwork needed.
Incorporated? Ask for the BN instead — never ask an incorporated subcontractor for a SIN. Keep QuickBooks permissions tight so only those who need supplier details can see them. If a sub won't share a SIN, request it in writing up to three times and keep a record of each attempt. We can still file, noting the reasonable effort.
The one rule
Never write a SIN on paper, in a spreadsheet, or in an email. Straight onto the QuickBooks supplier record — while you're on the call — is the safest home for it.