Bank reconciliation — what it catches, and what a skipped year costs

Reconciling is the least glamorous bookkeeping task and does the most work. Busy owners drop it first, assuming the bank feed imported everything. That is how unreconciled years happen, and an unreconciled year is an expensive thing to hand a CPA in Canada.

What bank reconciliation actually is

Reconciling is not clicking “match” on a bank feed. It is a proof. You take the closing balance the bank says you had, you take the closing balance your books say you had, and you explain every dollar of difference with items that legitimately exist, a cheque issued but not yet cashed, a deposit in transit, a card charge posted after the cut-off. If anything is left over that you cannot name, the books are wrong and you have found it while it is still small.

The feed is a convenience, not a control. It can drop transactions in an outage, import a day twice after a reset, and miss anything outside that account: a cheque paid personally, cash taken from a job, a transfer between company accounts recorded once.

What it catches in real Canadian books

Duplicated income. The most expensive error, because it flows straight through to tax. A deposit that lands twice inflates revenue, and the corporation pays tax on money it never received. Nothing in the books flags it; only the bank balance does.

Missing expenses. The reverse, and it costs the deduction. A charge that never imported is a deduction never claimed, and because it makes the balance look better, nobody investigates.

Transfers recorded once. Moving money between the operating account and a savings or tax-reserve account should have two entries. Recorded once, it becomes phantom revenue or a phantom expense.

Sales tax on the wrong side. If a deposit is coded to revenue without splitting out the GST/HST collected, your input tax credits and tax collected stop tying to the bank, and the return you file is a guess.

Payments that never cleared. An uncashed supplier cheque or CRA remittance shows only as a stale reconciling item. Find uncleared source deductions early; trust-fund arrears are treated far more seriously than ordinary debt.

Why the corporate angle changes the stakes

For a sole proprietor, unreconciled books mostly mean an inaccurate T2125. For an incorporated owner, the same problem propagates. The bank balance feeds the balance sheet, which feeds Schedule 100 of the T2. The revenue figure feeds Schedule 125 and the small business deduction calculation. The shareholder loan account — the one that determines whether money you took out has to be included in your personal income — is only reliable if every personal transaction that ran through the company account has been identified. Reconciliation is how they get identified. Owners running the software themselves without a CPA behind it will recognize the situation in QuickBooks but no accountant.

Unreconciled books also break the link between the corporate return and your personal one. If dividends declared do not agree to what actually left the bank, the T5 slips and the T2 stop telling the same story, and that inconsistency is visible to the CRA without any audit at all.

What a CRA reviewer asks for

When the CRA reviews a small business, it rarely asks for your books. It asks for bank statements, invoices and support for particular amounts, and works inward from those records. The CRA requires records supported by source documents and capable of verification. Reconciled books meet that; unreconciled books are a claim.

This is also why the reconciliation should be saved, not just performed. Keep the month-end statement, the reconciliation report and the list of outstanding items with your retained records, so the proof still exists years later when someone asks. If a letter does arrive, the guide to a pre-assessment review covers what to send.

What an unreconciled year actually costs

Three costs, only one of them a fee. Reconstruction: twelve months reconciled at once, from memory and archived statements, takes far longer than twelve monthly reconciliations. Tax paid on errors: duplicated deposits and missed expenses stay in the return unless found, and after filing, fixing them takes an adjustment. Decisions: you steered all year by numbers that were not true.

A fourth cost comes later: never-reconciled books have no clean starting point, so the first reconciled year opens on a balance nobody can prove. That is why catch-up work usually reconciles backwards to the last correct balance.

A workable monthly routine

Once the statement closes, reconcile every account the business touches — each bank account, credit card and payment processor. Confirm the closing balance agrees. List outstanding items and check that last month’s have cleared; anything still there after two months is usually an error. Review anything uncategorized before closing the period. Done monthly it takes little time, and it is the backbone of a proper month-end close.

This article is general information for Canadian business owners and is current as of July 2026. It is not tax, legal or accounting advice, and it does not create a client relationship. Tax rules change and your situation is unique, so please speak with a CPA before acting on anything here.