WSIB Clearance Certificates When Buying a Trades Business in Ontario

If you're buying an Ontario trades or construction business — an electrical contractor, a plumbing company, a general contracting firm — one due diligence step is easy to overlook amid the bigger questions of price, equipment, and contracts: confirming the seller's standing with the Workplace Safety and Insurance Board (WSIB).

Trades and construction are industries where workplace injury coverage through the WSIB system is central to how the business operates day to day. A buyer who skips checking the seller's WSIB standing isn't just missing a minor compliance detail — they can end up personally exposed to premiums the seller never paid.

Why This Matters More in Trades and Construction

Ontario's workplace insurance system, governed by the Workplace Safety and Insurance Act, 1997, generally requires many employers — particularly in construction and related trades — to be registered and to keep their premium payments current. Where a business is acquired, Ontario's framework can hold the purchaser responsible for the seller's outstanding WSIB premiums in certain circumstances, separate from whatever the purchase agreement says between buyer and seller about "assumed liabilities."

That's the key point: a purchase agreement that says the buyer isn't assuming the seller's debts is a matter between the two parties — it doesn't necessarily bind the WSIB or prevent the regulator from looking to the buyer if the seller's account isn't in good standing at the time of the sale.

What a Clearance Certificate Actually Confirms

A WSIB clearance certificate confirms that a registered business's account is in good standing — that is, it isn't in arrears — as of the time the certificate is issued. Getting one before closing gives a buyer documented confirmation of the seller's status at a specific point, which is the whole purpose of checking: you want to know before you close, not find out after.

A clearance certificate reflects a snapshot in time. Because a seller's account status can change, a certificate obtained too early in a deal timeline may no longer reflect the seller's actual standing by the time closing finally happens — which is why this is generally something to obtain close to the closing date, not weeks or months in advance.

Building It Into Your Closing Process

1. Confirm whether the seller's business is required to be registered with the WSIB — most trades and construction businesses with workers are, but coverage requirements can vary depending on the exact nature of the business, so confirm rather than assume.
2. Request a current clearance certificate as part of due diligence, and again close to the actual closing date given how status can change.
3. Make clearance a closing condition in the purchase agreement, so the deal isn't obligated to close if the seller can't produce current confirmation of good standing.
4. Address what happens if arrears turn up — whether through a price adjustment, a holdback, or a requirement that the seller resolve the arrears before closing.
5. Keep a copy of the certificate obtained at or near closing as part of your permanent deal records, in case the seller's status is ever questioned later.

Common Misconceptions

• "My purchase agreement says the seller keeps all their old liabilities, so I'm covered." That protects you in a claim against the seller, but it doesn't necessarily stop the WSIB itself from looking to the buyer for unpaid premiums where the framework allows it — a clearance certificate addresses the regulator's position directly, which contract language between the parties doesn't.
• "I got a clearance certificate at the start of due diligence, so I'm set." A certificate reflects the seller's status as of the date it was issued — obtaining one early and then closing much later can leave a gap where the seller's account changed in between.
• "This only matters for large construction companies." Smaller trades businesses with employees are commonly subject to the same registration and premium obligations, and the same successor-liability exposure applies regardless of size.

Frequently asked questions