A share sale does not reset the target’s relationship with the Canada Revenue Agency. The corporation you are about to own is the same taxpayer it was the day before closing, filing history included — so a gap between what it reported and what its own books show is exposure that survives the transaction.
Key takeaways
Reconciling tax filings to the internal accounts is a specific, mechanical comparison: the corporate income tax return (T2) for each of the last several fiscal years set against the internal financial statements or general ledger for the identical period, line by line, followed by the same exercise for GST/HST returns and payroll remittances. The question is not whether the two sets of numbers are close. It is whether every difference between them has a specific, checkable explanation.
A treadstonelaw.ca due-diligence checklist for Ontario business purchases puts the financial side of this plainly: buyers should “copies of corporate tax returns and notices of assessment for the past three to five years”, and separately verify HST registration status, that payroll remittances are current, and whether any CRA assessments or audits are outstanding.
The corporation itself carries a statutory duty to keep its own accounting records “until the expiration of six years from the end of the last taxation year to which the records and books of account relate” under section 230(4)(b) of the Income Tax Act. On a share purchase the buyer takes over that same corporation, which means the buyer also takes over whatever the CRA might still find inside those six years of records — a materially different exposure than an asset purchase, where the buyer generally acquires specific assets rather than the selling entity’s filing history.
This is exactly why a tax-specific holdback is a normal negotiating point on an Ontario share deal, not an unusual buyer demand. As one M&A answer puts it, a “tax-specific holdback is usually paired with a tax indemnity that lets the buyer draw on the held-back funds if the Canada Revenue Agency actually reassesses,” with the amount and duration “negotiated based on how real the CRA risk appears to be, often informed by the corporation’s own tax filing history.” A clean reconciliation is the evidence that makes that negotiation short; an unexplained gap is the evidence that makes it necessary in the first place.
Getting the review vs. audit question right on the underlying statements sits upstream of this — see when a review or audit engagement is worth requiring.
Two patterns come up repeatedly. The first is cash revenue that never shows up in the GST/HST return at the rate the sales ledger implies it should — deavo.ai’s own list of mistakes that lower a sale price names exactly this: cash sales that “do not reconcile against GST/HST filings”, alongside personal expenses run through the business and books that are not kept up to date. The second is a corporate tax return whose taxable income figure was arrived at through adjustments that never made it into the internal statements — a real and legitimate thing (capital cost allowance is not a book expense), but one your accountant needs to walk through line by line rather than accept as a rounding difference.
A due-diligence checklist deavo.ai publishes for first-time buyers puts the financial side of this at the top of the list: “tax and GST/HST filings checked against the statements” alongside two to three years of historical financials plus the current-year interim. It is worth reading with reviewing bank statements line by line, since a bank-record gap and a filing-versus-books gap are frequently the same underlying problem seen from two different angles.
It is worth knowing the CRA’s own fallback method, because it is a preview of what a post-closing reassessment could look like. When the CRA concludes it cannot verify income from a taxpayer’s own records, it can reconstruct income using a net worth audit — comparing assets and debts at the start and end of a period, adding back living expenses, and treating the resulting gap as unreported income. As the explanation puts it, this method is “generally a last resort, used when the CRA concludes it cannot verify income using the taxpayer’s own books and records,” and because it works backward from lifestyle and assets rather than forward from transactions, it “can surface a much larger reassessment than a conventional line-by-line audit.” A target whose books do not reconcile cleanly to its filings is, by definition, a candidate for exactly this kind of scrutiny — the CRA does not need your reconciliation to run one; you need it first.
The same logic extends to source deductions. Every person paying salary or wages in Canada is required, under subsection 153(1) of the Income Tax Act, to “deduct or withhold from the payment the amount determined in accordance with prescribed rules and… remit that amount to the Receiver General” at the prescribed time. Those amounts are held in trust for the Crown, not company cash the corporation is free to defer — so a target that has been late or inconsistent with remittances is carrying a liability that does not show up as a normal accrued expense on the balance sheet, and one that will land squarely on the corporation you are buying if it is a share deal. Checking remittance currency alongside the T2 and GST/HST reconciliation, rather than as a separate afterthought, is the efficient way to run this. What that obligation means for cash planning in the weeks right after closing is covered in cash management immediately after closing.
Suppose diligence turns up a target with T2-reported taxable income of $420,000 for the most recent fiscal year against internal pre-tax book income of $460,000 — both figures are illustrative, set here only to show the process. A $40,000 gap is not alarming on its own; CCA claimed for tax purposes routinely exceeds book amortization, and a handful of permanent differences (non-deductible meals and entertainment, for example) run the other way. The test is whether the accountant can walk the $40,000 to specific, named adjustments — and whether those same adjustments were applied consistently in the prior two years, not invented for the year under review. If the walk stops short by even a few thousand dollars with no candidate explanation, that residual is the number a holdback should be sized against, not waved past.
Less directly, since the buyer is acquiring specific assets rather than the selling corporation itself, and the seller’s corporation — not the buyer — generally remains the taxpayer of record for its own prior filings. It is still worth checking, because unpaid tax debts can attach to the assets or trigger clearance-certificate requirements depending on the tax in question, but the exposure is narrower than on a share deal.
Your own accountant, as part of financial due diligence — not the seller’s accountant, however cooperative they are. The point of the exercise is independent verification, and a reconciliation performed by the same firm that prepared the filings being checked does not serve that purpose.
That is the point at which a tax-specific holdback, tied to a tax indemnity, becomes the right tool rather than an escalation. It lets the deal proceed while directly protecting against the specific risk the unexplained gap represents, with the size and duration negotiated against how real that risk looks.
A short call is enough to map out what the reconciliation should cover before diligence starts, not after a gap surfaces.
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