Legal Due Diligence: The Contracts and Clauses That Can Sink a Sale
Most owners selling a business spend months getting the numbers ready and almost no time on their contracts. That is backwards. In my experience, more deals fall apart during legal due diligence than during the financial review, and the reason is almost always a contract the owner signed years ago and never thought about again.
A buyer’s attorney reads your agreements line by line. They are looking for anything that hands a customer, a landlord, a lender, or a partner the power to block the sale, walk away, or rewrite the terms after closing. When they find it, you lose leverage at the worst possible moment. The good news is that every one of these problems is findable before you go to market, while you still have room to fix it.
What is legal due diligence when you sell a business?
It is the buyer’s review of the legal backbone of your company. It runs alongside the financial review, but it asks a different question. The financial side asks whether your earnings are real. This side asks whether the buyer can actually own and operate what they are paying for, free of hidden claims and surprise obligations.
Your corporate records, litigation history, licenses, real estate, and employee agreements all get pulled into the review. But contracts get the hardest look, because contracts are where other people hold rights to your business. Getting ahead of that review is the core of real exit readiness, and it is the work we walk owners through on the sell side long before a buyer is ever in the room.
Why your contracts are where deals actually die
Owners brace for the financial review and get blindsided by the legal one. You can defend your margins. You know your numbers cold. What you may not remember is the clause buried on page nine of a customer agreement you signed back in 2019.
M&A contracts carry rights that belong to someone other than you. A key customer might have the right to approve any transfer of their agreement. A landlord might be able to terminate the lease the moment ownership changes. A lender might be able to call the loan. None of that shows up in your EBITDA. All of it shows up the day the buyer’s lawyer reads the fine print.
Which contracts does a buyer’s attorney actually read?
A buyer’s attorney does not skim. They build the equivalent of a contract review sheet, logging every material agreement and flagging anything that touches the sale. During the legal review, expect them to pull and read:
- Customer and supplier contracts, especially your largest accounts
- Real property and equipment leases
- Employment, noncompete, and key-person agreements
- Loan agreements, security agreements, and any personal guarantees
- Intellectual property licenses, both the ones you grant and the ones you depend on
- Insurance policies and any open or threatened litigation
The American Bar Association lays out how thorough this gets, down to tracking whether each contract needs consent to transfer. Their breakdown of the buyer-side review process is a clear look at the same scrutiny you are preparing to pass.
The contract clauses that can sink your sale
A handful of standard clauses cause most of the trouble. They are common, they are easy to miss, and any one of them can hand a third party control over your deal. These are the provisions worth finding in your own agreements before a buyer finds them for you.
Anti-assignment clauses
An anti-assignment clause says a contract cannot be transferred to anyone else without the other party’s consent. In an asset sale, where the buyer purchases your contracts one by one, this is the clause that bites hardest. If your biggest customer’s agreement carries an anti-assignment clause, that customer has to sign off before the contract can move to the buyer. A customer who senses the leverage can stall, renegotiate, or refuse outright. Suddenly your most valuable relationship is the reason the deal is stuck.
Change of control clauses
A change of control clause treats a shift in ownership as a triggering event, even when the contract itself never changes hands. This one matters most in a stock sale, where the buyer purchases the company rather than its assets. The entity stays the same. The lease, the loan, and the customer agreement all stay in the same name. But a change of control clause can still require consent, let the other party terminate, or let a lender call the loan, purely because you are no longer the owner. Asset sale or stock sale, the takeaway is the same. Read the consent and termination language in every material agreement, because the structure of your deal decides which clauses come alive.
Termination for convenience
Some contracts let a customer walk away on short notice for no reason at all. A termination-for-convenience clause with a 30-day window makes your revenue look fragile to a buyer, because income that can vanish on a month’s notice is not the dependable revenue it appears to be on a spreadsheet.
Exclusivity and noncompete provisions
Terms that restrict what your business can do travel with the sale. An exclusivity arrangement with a supplier, or a noncompete that limits the territory you can serve, becomes the buyer’s problem the day they take over. If those restrictions clash with the buyer’s plans, they turn into a reason to lower the offer or rethink the deal.
Personal guarantees
Obligations you signed in your own name do not disappear because the business changed hands. A personal guarantee on a lease or a loan has to be addressed, released, or replaced as part of the sale. Leave it unhandled and you can stay on the hook for a business you no longer own.
Rights of first refusal
A right of first refusal gives someone the first claim to buy before you can sell to anyone else. A minority partner, an early investor, or even a landlord might hold one. If they do, you cannot close with your chosen buyer until that party has had their shot, and that single provision can slow or sink a sale you thought was finished.
How a buried clause becomes a lower price, or a dead deal
Here is how a single clause turns into real money. When a buyer’s legal due diligence surfaces a consent you cannot get or a termination right you cannot remove, they do not simply absorb the risk. They price it.
That repricing shows up in familiar ways. The offer comes down. A chunk of the purchase price gets parked in escrow until the issue clears. The buyer demands an indemnification promise that makes you personally responsible if the problem resurfaces later. Or, on a closing condition the buyer will not waive, they walk.
The obligations you take on here do not end when the deal closes. The promises you make about your contracts become representations and warranties in the purchase agreement, and those can follow you for months or years after the sale. I covered how that works, and how it can bite long after the money hits your account, in this breakdown of representations and warranties.
What can cause a business sale to fall through, and how to get ahead of it
Most sales that collapse do not die over price. They die over surprises, and a contract clause nobody flagged until the buyer’s attorney found it is one of the most common surprises of all. The owners who clear legal due diligence cleanly are the ones who did the buyer’s homework first.
That work is straightforward, and you can start it today. Pull every material contract you have. Read the assignment, change of control, termination, and consent language in each one. Build a list of every party whose sign-off you will need to close. Then start resolving what you can, quietly, while time and leverage are still on your side. Fixing a problem on your own schedule is a negotiation. Fixing it under a buyer’s deadline is a fire drill.
The contracts that kill deals are almost always findable in advance. The only question is whether you find them first, or the buyer does.
A buried clause can sink a sale. See what your file would show a buyer.
