Seller's guide to due diligence in a business sale

Due diligence should validate — not discover.

When a buyer finds a surprise digging through your file, that’s no longer validation. It’s an investigation — and the negotiation dynamic shifts.

What due diligence is

Due diligence is the stage where the buyer reviews in detail everything the business has presented.

In the process of selling a business in Quebec, it kicks off after the signing of a letter of intent (LOI). The buyer has signaled serious interest, a base price has been agreed — and now they want to confirm that what they’re buying matches what they saw.

It’s the equivalent of a home inspection before purchase. The buyer isn’t second-guessing the decision to buy — they’re making sure the foundation is solid.

The analogy goes further: when an inspector finds a hidden defect, the deal doesn’t necessarily fall apart — but the price adjusts. The same logic applies to selling a Quebec SME.

For a Quebec SME, the typical timeline runs 4 to 8 weeks, sometimes longer depending on the complexity of the file.

It isn’t an interrogation. It’s a structured process, with defined areas and predictable requests. A well-prepared seller knows exactly what to expect.

The 5 areas the buyer checks

Due diligence systematically covers five major areas. For each one, the buyer has specific questions — and the seller needs the answers ready.

1. Financial

This is the most heavily scrutinized area.

The buyer verifies:

• normalized EBITDA and the quality of the adjustments
• the quality of revenue — recurring vs one-time, customer concentration
• financial trends over 3 to 5 years
• working capital and capex requirements

What the seller needs to provide: audited or reviewed financial statements (3 to 5 years), detail of EBITDA adjustments, breakdown of revenue by customer and by product.

2. Tax

The buyer wants to be sure the business is in compliance — and that there are no hidden tax risks.

They look at:

• tax filings from recent years
• notices of assessment
• tax credits claimed (SR&ED, etc.)
• any ongoing or potential tax disputes

What the seller needs to provide: filings and notices of assessment, documentation of tax credits, correspondence with tax authorities.

3. Legal

Contracts, litigation, and intellectual property get a fine-tooth-comb review.

The buyer verifies:

• customer and supplier contracts — change-of-control clauses, term, exclusivity
• commercial leases — assignability, remaining term
• ongoing or potential litigation
• patents, trademarks, and proprietary software

What the seller needs to provide: copies of all material contracts, intellectual property registry, status of litigation with estimated exposure.

4. Operational

The buyer wants to understand how the business runs day to day — and whether it can keep running after the deal.

They look at:

• the list of the top 10 customers and their share of revenue
• critical suppliers and dependencies
• the condition of equipment and assets
• documented (or undocumented) processes

What the seller needs to provide: customer and supplier lists, equipment inventory with age and condition, documentation of key operational processes.

5. Human resources

People are often the most valuable asset in an SME — and the most fragile in a transaction context.

The buyer verifies:

• who the key people are and their intent to stay
• employment contracts and non-compete clauses
• benefits and obligations
• the risk of departures after the deal

What the seller needs to provide: org chart, employment contracts for key people, detail of benefits, retention plan if available.

And depending on the industry: environment

For some SMEs — manufacturing, transportation, real estate, processing — an environmental layer often gets added to diligence.

The buyer may require a compliance check, a hazardous-materials review, or even a Phase I environmental study on the buildings.

The mistakes that kill deals

Due diligence doesn’t kill deals. What kills them are surprises, omissions, and the seller’s reactions — a recurring pattern in the files we work on.

Surprises

This is the most destructive mistake.

An undisclosed lawsuit. A major customer whose contract expires in 3 months. A latent tax issue.

When the buyer discovers something the seller didn’t mention, trust collapses. And once trust is lost, it’s very hard to rebuild.

The rule is simple: anything the buyer will discover, the seller should have disclosed first. Controlling the narrative changes the dynamic.

The textbook example: a deal that derailed after $50,000 in fees — a surprise in diligence that could have been anticipated months earlier.

Information drip-fed

Providing documents one by one, late, incomplete — even without bad intent — creates distrust.

The buyer wonders: “If it’s this hard to get a simple customer contract, what else aren’t they showing me?”

The defensive seller

The buyer asks questions — that’s their job. It isn’t a personal judgment on how you’ve run the business.

A seller who takes every question as an attack makes the process painful for everyone. A seller who answers factually and quickly sends a signal: this file is solid.

How to prepare

The best way to get through due diligence is to prepare for it before it starts.

Build a virtual data room upstream

A data room is an organized digital space where every document is filed by area — financial, tax, legal, operational, HR.

Building it before going to market — not in reaction to the buyer’s first request — changes the dynamic of the process.

Preparation begins well before diligence. The virtual data room (VDR) is the concrete deliverable.

Anticipate the hard questions

Every business has its sensitive zones — a dominant customer, a minor lawsuit, owner dependency.

Identifying them upstream and preparing a factual answer turns a potential problem into a point already addressed. It’s always better to be the one who brings it up first.

Another sensitive zone often overlooked by sellers: the buyer’s financial scenario after closing. The bank doesn’t finance a structure that suffocates the new owner — that’s why the buyer’s projected profitability decides whether the deal closes. A file that holds up to that test gets through diligence without late renegotiation.

Designate a point of contact

The owner shouldn’t handle the buyer’s requests alone during diligence. A broker or advisor coordinating exchanges filters requests, manages pace, and protects the seller from overload.

At RCA, coordinating diligence is an explicitly documented step in our sale advisory process.

The seller’s role during due diligence

During diligence, the seller has two main responsibilities.

Keep running the business

This is the most subtle trap: the owner gets so focused on the sale that they forget the business.

If revenue drops or a major customer is lost during diligence, the buyer will notice — and the price will adjust.

The business has to run normally, as if no transaction were underway.

Stay available and factual

Respond quickly. Provide complete documents. Answer questions without taking them personally.

Due diligence isn’t a judgment on the owner. It’s a structured process that lets the buyer confirm the decision.

A cooperative seller speeds up the process. A difficult seller slows it down — and every day of slowdown raises the risk that the deal won’t close.

If you want to know whether your file is ready for diligence, a confidential valuation helps identify the areas to work on before going into process.