TREADSTONE LAW · ONTARIO · DIGITAL LEGAL SERVICES · EST. MMXXI ·TSL
Corporate · Document Checklist · 10 min

Buying a Business in Ontario: The Due Diligence Document Checklist

Everything to ask for, and why it matters, before you sign and pay.

Last reviewed 2026-06

Everything to ask for, and why it matters, before you sign and pay.

Who this is for: Anyone buying an existing business in Ontario — a buyer, a co-founder, or an owner-operator stepping into someone else's company. What you'll get: a grouped, ready-to-send document-request list, plus a plain-language map of how a purchase moves from a handshake to a signed deal.

⚖️ This is a general guide, not legal advice. It can't account for your specific situation. Use it to get oriented, then confirm the details with a licensed Ontario lawyer.


Why due diligence matters

Due diligence is the homework you do before you buy — gathering and reviewing the seller's documents so you understand exactly what you're getting. You're checking three things: that the business is what the seller says it is, that it owns what it claims to own, and that no hidden liabilities (debts, lawsuits, broken contracts) will land on you after closing.

The single most important habit: get it in writing, and get it from the source. A verbal "we have no debts" is worth nothing if a creditor shows up after you've paid.


First, the big fork: asset deal or share deal?

How you buy changes what you're buying — and what you need to review. Understand this before you build your request list, because it drives everything that follows.

Asset purchaseShare purchase
What you buySelected assets (equipment, inventory, name, goodwill, contracts)The shares of the corporation that owns the business
LiabilitiesYou generally pick what you take on; old debts usually stay with the sellerYou inherit the whole company — including unknown liabilities
Contracts/leasesOften must be re-signed or assigned (landlord/customer consent)Usually carry on automatically, since the company is unchanged
Due diligence focusThe specific assets and the contracts you're assumingThe entire history of the corporation
Typical buyer preferenceBuyers often prefer it (cleaner liability)Buyers accept more risk; sellers often prefer it for tax reasons

💡 Why it matters: Sellers often favour a share sale for tax reasons (see our tax guides on the lifetime capital gains exemption). Buyers often favour an asset sale to leave old liabilities behind. The structure is negotiable and has real tax and legal consequences for both sides — settle it early.


How a purchase flows (so you know where you are)

  1. Letter of Intent (LOI). A short, mostly non-binding document setting out price, structure, and key terms — the framework. Confidentiality and exclusivity clauses in it usually are binding.
  2. Due diligence. You request and review the documents below. This is where deals are saved or killed.
  3. Definitive agreement. The binding Asset Purchase Agreement or Share Purchase Agreement, with the representations, warranties, and conditions.
  4. Closing. Money and ownership change hands; documents are signed and delivered.
  5. Transition. The seller helps hand over, often under a non-compete and a short transition period.

⚠️ Watch out: Start your due diligence document requests the moment the LOI is signed. Reviewing 200 documents takes time, and missing items are the most common cause of a delayed or collapsed closing.


The document-request list

Send this to the seller (and their lawyer/accountant) as your formal request. Tick items as you receive and review them — receiving a document isn't the same as understanding it.

1. Corporate records

Where they come from: the seller's minute book and corporate counsel.

💡 Why it matters: A disorganized or incomplete minute book is a red flag and a real problem — in a share deal especially, you're buying the corporation's paperwork as much as its business. Gaps here can stall closing.

2. Financial records

Where they come from: the seller's accountant and bookkeeper.

DocumentLook for
Financial statements (3–5 years)Trends, sudden swings, one-time items
Year-to-date interim statementsRecent performance vs. last year
Corporate tax returns (3–5 years)Consistency with the statements; any reassessments
HST/GST filings and any sales-tax accountsFiled and paid on time?
Payroll records and source-deduction remittancesNo arrears to the CRA
Accounts receivable agingHow collectible are the receivables, really?
Accounts payable and a full list of debts/loansWhat you might inherit
Bank statements and loan/security agreementsLiens against the assets

💡 Why it matters: A PPSA search (Personal Property Security Act registry) reveals who has a legal claim against the business's assets. You don't want to buy equipment a bank can repossess.

3. Material contracts

Where they come from: the seller's records; confirm assignability with the lawyer.

⚠️ Watch out: Customer concentration is a classic hidden risk. If one client is 40% of revenue and their contract can be cancelled on sale, the business may be worth far less than it looks.

4. Employment

Where they come from: HR records and the seller's payroll provider.

💡 Why it matters: In an asset deal, employees don't come with the assets — you decide who to offer employment to, and anyone left behind can trigger termination and severance costs. For those you do hire, the ESA deems their years with the seller to count as years with you. In a share deal, all employment obligations carry over to you. Either way, accrued vacation and severance exposure are real liabilities — price them in.

5. Intellectual property

Where they come from: the seller, CIPO records, and domain registrars.

⚠️ Watch out: A surprising number of small businesses don't actually own their own logo, website, or code — a freelancer built it and never signed an assignment. Confirm the company holds clear title to its brand and tools.

6. Litigation and disputes

Where they come from: the seller and their lawyer.

7. Permits, licences, and regulatory

Where they come from: the seller, the municipality, and provincial regulators.

8. Assets and operations

Where they come from: the seller's records and a physical inspection.


Representations, warranties, and the non-compete

Due diligence finds problems; the agreement allocates the risk of problems you didn't find.

💡 Why it matters: You're not just buying assets — you're buying goodwill. A reasonable non-compete protects that goodwill. Your lawyer will draft it to be enforceable rather than wishful.


Who does what: your lawyer and your accountant

RoleThe lawyerThe accountant
StructureAdvises on asset vs. share and drafts the dealModels the tax outcome of each structure
DocumentsReviews contracts, leases, corporate records, IP, litigationReviews financials, tax filings, and quality of earnings
RiskDrafts reps, warranties, indemnities, holdback, non-competeVerifies the numbers and flags financial red flags
ClosingManages signing, PPSA searches, and transfer documentsConfirms working capital and post-closing adjustments

You need both. Bring them in before the LOI is final — early advice is cheaper than fixing a bad deal later.


Mini-FAQ

How long does due diligence take? It varies — confirm with your advisors. A small, clean business can take a few weeks; a larger or messier one, a few months.

Can I back out if I find something bad? Usually yes — a well-drafted LOI and agreement make closing conditional on satisfactory due diligence. That's exactly what these conditions are for.

Do I really need all of this for a tiny business? Scale it to the deal, but don't skip categories — the smallest businesses often have the messiest records. The corporate, financial, and lien (PPSA) checks are non-negotiable.


How Treadstone Law can help

Treadstone Law guides Ontario buyers through business purchases from the letter of intent to closing — running the legal due diligence, drafting and negotiating the purchase agreement, handling PPSA and corporate searches, and structuring reps, warranties, holdbacks, and the non-compete so you're protected after the deal closes.


This is not legal advice

This guide is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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Sources

Links go to the official consolidated text. Legislation changes — confirm you are reading the current version.

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These guides are general information, not legal advice. Reading one does not create a lawyer–client relationship. For advice about your situation, speak with a licensed lawyer — call 1-844-900-1070.

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