Due Diligence Checklist for Sellers: What Buyers Request Before Closing

Due diligence is a determining factor in the business sale process, and with good reason. Think of it from a buyer’s perspective. They’re investing huge sums in a business they intend to own, control, be responsible for, and hopefully scale and profit from, so they really want to make sure they’re getting the attractive proposition that a seller has advertised. Due diligence lets them do that, verifying every aspect of the business is in order.

The following checklist will help you understand what you must bring to the table for due diligence when you’re selling a business.

What Is Due Diligence and Why Does It Matter for Sellers?

We just explored why due diligence is important to buyers, but it’s surprisingly advantageous for sellers too. Since due diligence is the process of rigorously examining your internal documentation, it’s an opportunity for you to display everything in the best light possible. But if things aren’t in order, it can cause closing delays, reduce sale price, and even make a once eager buyer say no deal.

So prepare the following information well  before due diligence gets underway.

The Due Diligence Checklist: What Buyers Will Request

Financial Documents

3 years of tax returns: Every business owner should have tax returns appropriately ordered and archived, and during due diligence you can’t do without them.

Profit and loss statements: P&L statements give buyers a clear picture of your revenue trends, cost structure, and profitability over time. They're looking for consistency, growth trajectory, and any irregularities that might signal hidden risk or inflated earnings.

Balance sheets: The balance sheet gives buyers a snapshot of your business's financial health at a specific point in time, what you own, what you owe, and what's left over. Buyers use it to assess liquidity, understand debt load, and determine whether the business has the financial footing to support their investment and future growth plans.

EBITDA calculations and normalized earnings: EBITDA (earnings before interest, taxes, depreciation, and amortization) is the most common starting point for valuing a business, as it reflects operating profitability stripped of financing and accounting variables. Normalized earnings take that a step further, adjusting for one-time expenses, owner perks, and anomalies that wouldn't carry over to a new owner. Together, these numbers give buyers the clearest possible picture of what the business actually earns, and what it's worth.

Legal Documents

Business licenses and permits: Buyers need to confirm that every license and permit required to operate your business is current, properly maintained, and transferable. Lapses or gaps here can create legal exposure, delay closing, or require costly remediation before a deal can move forward.

Contracts with customers and vendors: Customer and vendor contracts reveal the stability and depth of your key business relationships. Buyers want to understand contract lengths, renewal terms, exclusivity arrangements, and any clauses that could be triggered by a change in ownership, all of which directly affect business continuity and value.

Lease agreements: Whether it's your physical location, equipment, or other infrastructure, lease agreements tell buyers what operational assets are locked in, at what cost, and for how long. Favorable long-term leases can be a selling point; short-term or expiring leases may raise concerns about stability. 

Any ongoing or past litigation: Undisclosed legal issues are one of the fastest ways to derail a deal. Buyers will scrutinize any current or historical litigation to understand potential liabilities, regulatory exposure, or reputational risk that could follow them into ownership. Full transparency here is always the better path.

Operations

Organizational chart: An org chart gives buyers clarity on how the business is structured and who is responsible for what. More importantly, it helps them assess whether the business can operate effectively without the current owner, a critical factor in determining risk and transition planning. 

Employee agreements and key personnel information: Buyers want to understand who the key people are, what keeps them in place, and what happens if they leave. Employment agreements, non-competes, compensation structures, and any retention arrangements all factor into how a buyer evaluates operational stability post-closing.

Standard operating procedures: If critical knowledge lives only in the heads of the owner or a handful of employees, that's a red flag for buyers. Documented SOPs demonstrate that the business runs on systems, not just people, making it far more transferable, scalable, and valuable in the eyes of a prospective buyer. 

Equipment and inventory lists: A complete, accurate accounting of equipment and inventory gives buyers a clear picture of the tangible assets they're acquiring. Condition, age, and replacement costs all factor into valuation, and surprises in this area, missing assets or undisclosed liabilities, can erode trust quickly.

Sales & Customer Information

Customer concentration data: Buyer concern spikes when a large percentage of revenue comes from a small number of customers. Concentration data helps buyers assess how vulnerable the business is to customer loss and whether the revenue base is diversified enough to weather normal customer churn after a transition.

Recurring revenue documentation: Recurring revenue is one of the most attractive qualities a business can have. Documentation of subscriptions, retainers, long-term contracts, or repeat purchase patterns gives buyers confidence that cash flow will continue after closing, and often supports a higher valuation multiple.

Sales pipeline and history: Historical sales data and a well-documented pipeline tell buyers where revenue has come from and where it's headed. They're looking for consistent growth, healthy channel diversity, and evidence that the business isn't overly dependent on any single relationship, geography, or sales method that might not survive an ownership transition.

How to Prepare Before the Due Diligence Process Begins

Don't wait for a buyer to ask: organize documents in advance

Organized financial, legal, and process documentation keeps your business running smoother in general, and makes selling easier when the time comes. Start early, don’t rush!

Clean up financials and address any red flags proactively

The middle of a meeting with a potential buyer is the wrong time to encounter an inexplicable number in your financials. Audit yourself thoroughly and resolve disparities; so you’re not stammering through excuses and confessions mid-sale.

Ensure contracts, licenses, and legal documents are current

Anything your business does should be backed up with the applicable up-to-date contracts, documents, and licensing.

Handling due diligence correctly can speed up closing and improve your valuation, if you’re prepared. Preparation isn’t easy, but an M&A advisory firm can help.

Why You Need an M&A Advisory Firm During Due Diligence

Due diligence puts every aspect of your business under the microscope. Even the most hands-on control of your business likely won’t prepare you for everything a buyer will dig into.

An M&A advisory firm can.

Having undertaken the business sales preparation process hundreds of times or more, a good M&A advisor knows exactly the questions a seller can expect from a buyer. Where weaknesses exist, they can help fix them. They make sure word doesn’t get out, so employee anxiety doesn’t rattle operations and tank business value. And at the negotiating table, they know when and how to push back, to keep a solid deal moving without making damaging concessions.

If you’re inexperienced at selling, buyers can get you to settle for less. An M&A advisor is savvy to aggressive buyer tactics, knows how to present your business, and can protect your interests and your business’ value while sealing a solid deal.

Preparation Is Your Strongest Asset at the Closing Table 

Preparation makes all the difference in due diligence. An organized company looks better, feels more trustworthy, and may sell quicker at a better value.

IBG Business can help you get there. Contact us to request a confidential conference now, so when due diligence arrives, you’ll be prepared!

Frequently Asked Questions

How long does the due diligence process typically take? It varies by deal size and complexity, but most business sales involve a due diligence period of 30 to 90 days. The more organized your documentation is going in, the faster it tends to move.

What happens if a buyer finds a problem during due diligence? It depends on the issue. Minor problems may be resolved through price adjustments or seller concessions. More serious issues, undisclosed liabilities, legal exposure, or financial discrepancies, can delay closing or cause a buyer to walk away entirely. This is why proactive self-auditing matters.

Can due diligence affect my sale price? Absolutely. A clean, well-organized due diligence process reinforces buyer confidence and supports your asking price. Messy records, gaps in documentation, or unresolved issues give buyers leverage to negotiate you down.

Do I have to share everything with a buyer during due diligence? Buyers will request comprehensive access, but disclosures are typically governed by a confidentiality agreement signed before the process begins. An M&A advisor can help you manage what's shared, when, and with whom, protecting sensitive information while keeping the deal on track.

What's the most common mistake sellers make in due diligence? Waiting too long to prepare. Many sellers underestimate how much documentation a buyer will request and scramble to pull it together under pressure. Starting the organization process well before you go to market puts you in a far stronger position.