CRA Reassessment: A Bookkeeping Cleanup Guide

A CRA reassessment notice lands, and the questions start immediately. What changed? Why did it change? Does the bookkeeping actually support what was reported? For business owners, it can feel like an accusation. In reality, it's usually just a flag that something in the numbers needs a second look.

A reassessment often points to one of a handful of familiar culprits: missing documentation, expenses filed under the wrong category, GST/HST mismatches, deductions that lack proper backup, or transactions that were never fully reconciled. None of that automatically means wrongdoing. It usually means the books need attention before you respond.

At NCSGX, we work with Canadian businesses to keep their records organized, accurate, and properly documented. When a CRA review uncovers gaps, the fix isn't cosmetic. It's a genuine bookkeeping cleanup that creates a clear, defensible trail for this filing and every one after it.

Key Takeaways

• A CRA reassessment doesn't automatically signal an intentional error. Start by understanding exactly what CRA changed and why.
• Compare the notice of reassessment against your filed return, your bookkeeping records, and your supporting documents.
• Catch-up bookkeeping can surface unreconciled accounts, missing records, GST/HST discrepancies, and other errors that need correcting.
• If you disagree with the reassessment, know the difference between supplying information, requesting an adjustment, and filing a formal notice of objection.
• Track the applicable deadline closely, and keep a clear record of everything you submit to CRA.

What a Reassessment Notice Actually Means

A notice of assessment is CRA's initial read on a filed return. A notice of reassessment is a later revision to that assessment. Getting one isn't evidence of fraud or intent to mislead. Adjustments happen for ordinary reasons: information was missing, figures didn't line up with CRA's own records, a deduction wasn't sufficiently backed up, or CRA simply reached a different conclusion than you did.

For corporations, the standard T2 reassessment window is typically three years from the original notice of assessment for a Canadian-controlled private corporation (CCPC), and four years for corporations that don't qualify as CCPCs. Exceptions exist, including cases involving neglect, carelessness, wilful default, fraud, or specific waivers and adjustments.

What to Do the Moment the Notice Arrives

Before touching your books or picking up the phone to CRA, work through this:

• Read the full notice, not just the summary.
• Confirm which tax year or reporting period is affected.
• Pinpoint exactly what changed, whether it's income, expenses, deductions, credits, GST/HST, interest, or penalties.
• Line up the notice against your originally filed return and your accounting records.
• Read CRA's stated explanation for the adjustment.
• Check every deadline tied to a response or objection.
• Pull together supporting records before drawing conclusions.
• Bring in professional help if the issue is technical, significant, or likely to be disputed.

Deadlines aren't flexible. For a Canadian corporation, a formal income tax objection generally needs to be filed within 90 days of the notice of assessment or reassessment.

Why the Books Need a Real Cleanup

A CRA review often surfaces problems that were sitting in the books long before the notice showed up. Cleaning them up is how you determine whether the reassessment actually holds up against the real transactions.

Issue	What It Can Cause	What to Review
Unreconciled bank accounts	Incorrect income or expenses	Bank statements and ledger
Missing receipts	Unsupported deductions	Receipts and proof of payment
Duplicate transactions	Inflated expenses	Transaction listings
GST/HST discrepancies	Incorrect net tax or ITCs	GST/HST reports and invoices
Payroll discrepancies	Incorrect liabilities	Payroll reports and remittances

Catch-up bookkeeping matters most when records have fallen behind or contain gaps. But it's more than backfilling old entries. CRA defines business records broadly, covering ledgers, financial statements, invoices, receipts, contracts, and bank statements that support your transactions.

A Practical Workflow for Correcting the Books

1. Identify what CRA changed. Build a simple reconciliation between your original filing and CRA's adjustment, and quantify each difference.
2. Reconcile the affected accounts. Go through bank accounts, credit cards, GST/HST accounts, payroll liabilities, loans, and accounts receivable/payable. An unreconciled balance can bury the exact transaction causing the issue.
3. Trace transactions to source documents. For anything material, match the ledger entry back to the invoice, receipt, contract, or bank record.
4. Correct the errors. Fix duplicates, wrong classifications, missing entries, or unsupported amounts, and document why each change was made rather than quietly overwriting history.
5. Review the GST/HST impact. Confirm sales and purchases were treated correctly and that any input tax credits claimed are properly supported.
6. Reconcile tax and liability accounts. Compare your accounting balances against CRA statements and filed returns, and dig into anything that doesn't line up.
7. Document every correction. Note what changed, why, which source document backs it up, and when the adjustment was made.
8. Build a clean review trail. Anyone unfamiliar with the file should be able to follow a transaction from source document through bookkeeping entry, reconciliation, tax return, and CRA response.

Building Your Supporting Documentation Package

What you need depends on what CRA is reviewing, but a solid package generally includes:

• Sales and purchase invoices
• Receipts and proof of payment
• Bank and credit-card statements
• Payroll records
• GST/HST records and working papers
• Accounting ledgers and journal entries
• Financial statements
• Documentation explaining business purpose

CRA generally expects records and supporting documents to be kept for six years from the end of the last tax year they relate to, though some records, such as long-term property or corporate historical documents, may need to be kept longer or indefinitely.

Three Ways to Respond to CRA

Keep these distinct, since each follows a different process:

Providing requested information. If CRA asks for documents during a review, supply them by the stated deadline. Without a response, CRA can base its decision on whatever information it already has.

Requesting a reassessment or adjustment. If you find an error in a previously filed amount, the correction process depends on the return type. Corporations can request a T2 reassessment electronically or in writing, along with supporting information.

Filing a formal notice of objection. If you disagree with an assessment or reassessment, this is the formal dispute route. For corporations, the deadline is generally 90 days from the notice date. The objection needs to lay out the disputed issue, the facts, the reasoning, and the supporting documentation. Corporations can typically file online through My Business Account, or through Represent a Client if an authorized representative is involved.

Preventing a Repeat

A bookkeeping routine that's CRA-ready from the start is almost always cheaper and less disruptive than reconstructing years of records after the fact. Consistency is the whole strategy:

• Reconcile bank and credit card accounts every month.
• Review GST/HST payable and input tax credit accounts on a regular basis.
• Keep invoices and receipts organized in digital folders.
• Keep personal and business spending fully separate.
• Review accounts receivable and payable balances monthly.

The Bottom Line

A CRA review or reassessment is, in its own way, a useful prompt to look closely at your bookkeeping, your documentation, and how you report. Addressing the discrepancies, documenting every correction, and keeping records organized builds a stronger foundation for future filings and any future correspondence with CRA. If your business needs help catching up its books or closing bookkeeping gaps, reach out to NCSGX to talk through what you need.