Input Tax Credit Recovery: How to Reclaim the GST/HST Hiding in Your AP Ledger

Free money? Yes — and your business is probably sitting on some of it.

Most Canadian business owners are surprised to learn that there is a small pile of cash sitting inside their own accounting system. Not theoretical money. Not future revenue. Actual dollars they already paid out — to suppliers, contractors, software vendors, hotels, fuel cards, you name it — and are legally entitled to recover from the Canada Revenue Agency or a provincial tax authority.

It happens in every business, of every size. Bookkeepers miss tax codes. Invoices arrive with the GST/HST line buried in fine print. PST gets charged on exempt items. Employee expense reports get summarized without proper tax breakouts. Multiply those small misses by thousands of transactions a year, and the result is real money — money the government is happy to keep if you do not ask for it back.

That is what input tax credit recovery does: it finds those missed tax dollars, documents them properly, and gets them back into your business.

What input tax credit recovery actually means

In Canada, the GST/HST and Quebec's QST work on a value-added tax (VAT) principle. When you, as a registered business, pay GST/HST or QST on something you bought for your commercial activity, you are entitled to claim that tax back as an input tax credit (ITC) on your next return. It nets against the tax you collected from your own customers, so you only remit the difference.

The catch is that you actually have to claim those credits. If your supplier charged you HST and your bookkeeper coded the invoice as "no tax" — or coded it as the wrong tax type, or missed it entirely because the supplier's invoice format was unusual — that ITC goes unclaimed. It does not trickle in later. It sits in your AP ledger as silent overpayment until someone goes looking for it.

It is the same story for the Quebec Sales Tax (QST), which has its own input tax refund mechanism that mirrors the federal ITC system.

Provincial sales tax (PST in British Columbia, Saskatchewan, and Manitoba) works differently — there is no general "input credit" mechanism — but PST recovery opportunities still exist. Businesses routinely get charged PST on items that are exempt: production machinery, goods purchased for resale, certain agricultural inputs, and so on. Those overpayments can be reclaimed through provincial refund applications. They simply do not get caught unless someone is specifically looking.

When we refer to "tax recovery" or "input tax credit recovery" in this article, we are using it as shorthand for all of it: federal GST/HST, Quebec QST, and provincial PST opportunities your AP ledger may be hiding.

Why this is a "thing" in the first place

Here is the honest reason this niche exists: tax recovery work is detail work, and detail work is exactly what gets skipped when a business is busy.

The companies we work with have competent bookkeepers and reputable accountants. Their books are clean. Their returns get filed on time. Recovery opportunities still exist because:

• A mid-sized business runs thousands of AP transactions a year. A 1% error rate is mathematically certain at that volume — and 1% against an AP base in the millions is meaningful money.
• Coding shortcuts. When an invoice does not clearly break out tax, the path of least resistance is to code it "no tax" and move on. This is especially common with foreign vendors, cross-border purchases, and SaaS subscriptions.
• Pass-through expenses. T&E reports, corporate card reconciliations, and employee reimbursements are notorious for hiding embedded tax. The summary line on an expense report rarely captures it.
• PST charged in error. Provincial PST gets charged on plenty of items that qualify for exemption. Once it is paid, only a deliberate recovery review will catch it.
• System changes. Migrations between accounting systems, mergers, acquisitions, and finance team turnover all create periods where tax coding goes off the rails.
• Documentation gaps. The CRA requires specific information on a supporting invoice for an ITC to be valid. If that information was missing at the time, the ITC may have been correctly skipped. But often the underlying documentation does exist — it just was not gathered.

None of this means anyone did anything wrong. It means modern AP is messy, and a periodic recovery review is good hygiene, like a plumber checking your pipes.

"Free money" — is it really?

Let us be precise about what "free money" means here, because we do not like vague claims.

The dollars are already yours. You paid them. The question is not whether you can find a tax dodge or a loophole — there is no aggressive tax planning involved. The question is whether you can properly document and claim back tax you were already legally entitled to recover. This is straightforward tax recovery, the same way you would recover an overpayment to any other vendor.

It hits your bottom line dollar for dollar. Unlike a deduction that saves you a fraction of the dollar in tax, a recovered ITC or PST refund is the full dollar coming back.

And in many cases — including ours — the assessment that tells you how much you are owed is free.

The 4-year window: why timing matters

The CRA gives most GST/HST registrants four years from the due date of the return for the period in which the ITC could first have been claimed. After that, the credit is statute-barred. It is gone.

Some businesses — including listed financial institutions and registrants with annual taxable supplies above $6 million in each of the two preceding fiscal years — get only two years. Provincial PST refund windows vary by jurisdiction.

The practical implication: every month that passes, a slice of recoverable tax ages out. If you have not done a recovery review in three or four years, you are at the threshold where money is starting to evaporate.

How a free recovery assessment works

What we need from you

Two things, both read-only:

1. Access to the AP side of your accounting system, or a clean export of AP transactions over the review period. Read-only is fine. We do not need to post, edit, or change anything.
2. The supporting documents. In modern accounting platforms — QuickBooks Online, Xero, Sage Intacct, NetSuite, Acumatica, Dext, Hubdoc, and similar — the source invoice is usually saved as a PDF attached directly to the transaction. That attachment is the gold we are looking for. It tells us the actual tax breakdown, the supplier's GST/HST number, the jurisdiction, and everything else needed to validate or correct the original coding.

That is it. No interviews with your team. No banker boxes.

What we do with it

We run a structured review that compares each transaction's coded tax against the tax that should have been claimed based on the supporting document. The output is a categorized list of potential recoveries, segmented by tax type (GST/HST, QST, PST) and by reason — miscoding, missed claim, exemption opportunity, documentation gap, and so on.

What you get back

An estimated recovery range, the categories where opportunities are concentrated, and a recommendation on whether a full recovery engagement makes sense. Honest answer: sometimes it does not. Some AP ledgers are tight, and we will tell you so. The free assessment is the filter.

Then what?

If the numbers justify a full engagement, we agree on scope and fees up front — typically contingency-based, meaning we are paid out of what we actually recover. You have no cost if we do not deliver. If the numbers do not justify it, you keep the assessment and we shake hands.

Why this is so much easier than it used to be

A decade ago, a tax recovery review meant hauling banker boxes of paper invoices into a conference room. Reviewers would sample, extrapolate, and miss things. Engagements took months.

Today, most AP departments save the source document as a PDF attached to the transaction. That single shift changes everything. We can scan thousands of transactions, with their supporting documents, in a fraction of the time — and instead of sampling, we can review the full population. The result is a more accurate recovery estimate, faster, and with far less disruption to your team.

If your business is already in this digital state — and most are by 2026 — you are sitting on a recovery opportunity that has never been easier to surface.

Who benefits most from a recovery review

You will likely find the most in your AP ledger if any of these apply:

• High AP transaction volume (thousands of transactions per year).
• Operations across multiple Canadian provinces or both federal and provincial sales tax regimes.
• A mix of taxable and exempt or zero-rated activities.
• Significant capital expenditures, fleet, or fuel purchases.
• Frequent cross-border purchases or foreign vendor invoices.
• Heavy T&E or corporate card spend.
• A recent system migration, merger, acquisition, or finance team transition.

Smaller businesses can benefit too. The dollars are smaller in absolute terms, but the percentage hit rate is often just as high.

Frequently asked questions

Will a recovery review trigger a CRA audit?

No. Filing an amended return or a properly documented ITC claim is a routine matter. The CRA expects registrants to correct missed credits and overpayments — that is precisely why the four-year window exists.

Is my financial data secure?

Yes. We work under a written engagement and confidentiality agreement, with read-only access wherever possible. Your data does not leave a controlled environment.

Do I have to file amended returns?

In most cases, missed GST/HST ITCs can be claimed in the current period's return rather than by filing amendments — the CRA explicitly permits this within the four-year window. PST refunds usually require a separate provincial refund application.

What is the fee?

The initial assessment is free. If a full engagement is warranted, fees are typically contingency-based — a percentage of what we recover. You do not pay unless you collect.

How long does the assessment take?

For a typical mid-sized AP ledger with PDFs attached to transactions, an initial assessment takes days, not weeks.

What if my accountant already looked at this?

Most accountants do excellent compliance work, but a focused recovery review is a different skill — looking for what is missing rather than confirming what is there. The two are complementary, not competing.

How to get started

If you would like to find out whether there is recoverable tax sitting in your AP ledger, we will do the assessment at no cost and no obligation.

Bring us read-only access to AP, the supporting documents, and a willingness to learn how much is there. We will do the rest — and within days, you will know whether it is worth pursuing.

The money is already yours. The only question is whether you ask for it back.

Use our recovery calculator to get a quick estimate, or reach out directly to start your free assessment.

*This article was originally published on Gateway Tax by Andrew Adolph, CPA and former CRA auditor with 25 years of experience. Andrew is a tax advisory partner at Gateway Tax and Input Recovery.*