Due Diligence
What Happens During Due Diligence?
Due diligence can make or break your sale. See what buyers investigate, how a 60-day timeline unfolds, and how to handle a retrade without losing the deal.
Quick answer
Due diligence is the buyer's formal investigation of your financials, legal standing, operations, and customers after a letter of intent is signed, typically lasting 30 to 90 days. The buyer's accountant, attorney, and lender verify that what you told them during negotiations is actually true, and any gap between your story and the evidence gets priced into the deal or ends it.
Key Takeaways
- Due diligence begins once a letter of intent is signed and usually runs 30 to 90 days under an exclusivity period that blocks you from shopping the deal elsewhere.
- The buyer's team typically includes their accountant or quality of earnings firm, their attorney, their lender, and sometimes industry, insurance, or environmental specialists.
- Financial diligence exists to confirm your earnings are real, sustainable, and transferable to a new owner, not just to check that your numbers add up correctly.
- Retrades, where a buyer lowers the price mid-process, are common; some are legitimate responses to new information and others are pressure tactics that deserve pushback.
- The single biggest thing that kills deals in diligence is a seller who hides a problem instead of disclosing it early.
- Working capital gets settled during diligence through a true-up calculation that can move your proceeds by a meaningful amount at closing.
- A seller who runs their own sell-side diligence before going to market avoids most of the surprises that sink deals later.
- If part of your payment involves a seller note, an earnout, or an equity rollover, you owe it to yourself to investigate the buyer just as hard as they investigate you.
01 · Fundamentals
What Is Due Diligence and When Does It Start?
Due diligence is the formal investigation a buyer conducts to verify that everything you represented about your business during negotiations is actually true. It starts after both sides sign a letter of intent, which sets the price and terms and grants the buyer a period of exclusivity, usually 30 to 90 days, during which you agree not to shop the deal to other buyers.
That exclusivity is the trade. You give up your leverage to negotiate with other parties, and in exchange the buyer commits real time and money to confirming the deal is what you said it was. Before the LOI, most of what a buyer knows about your business comes from a summary, high-level financials, and your answers in meetings. Diligence is where that story gets tested against evidence: tax returns, bank statements, contracts, and the people who actually work in the business.
02 · Perspective
Who Sits on the Other Side of the Table
Once diligence starts, you are no longer negotiating with one buyer. You are dealing with a team, and each member is looking for a different kind of risk.
Most buyers bring in an accountant or a quality of earnings firm to dig into your financials, a transaction attorney to review contracts and legal exposure, and a lender if the deal involves financing, since banks and SBA lenders run their own underwriting on top of the buyer's review. Depending on your industry, the buyer may add an operations consultant who understands your specific trade, plus insurance and environmental specialists if your business involves real estate, fleet vehicles, or regulated processes. Any one of them can independently slow the deal down or raise a flag that changes the price.
03 · Buyer View
What Buyers Actually Investigate
Financial Due Diligence
Financial diligence is not about catching you in a lie. It is about confirming that the earnings you presented are real, sustainable, and will still be there for the new owner. The buyer's accountant or quality of earnings firm ties your reported financials to your tax returns and bank statements, line by line, looking for any gap between what you claimed and what actually moved through your accounts. They test how you recognize revenue, whether your margins have trended up or down, and they scrutinize every add-back on your SDE or EBITDA schedule, since add-backs are where sellers most often oversell.
A quality of earnings review, in plain terms, is a normalized look at your true, recurring cash flow, stripped of one-time events and personal expenses, so the buyer can trust the number they are paying a multiple on. A residential plumbing company we advised on took a meaningful share of its revenue in cash, and the owner could not produce bank records tying those deposits back to reported income. The buyer's accountant flagged it immediately, and the price came down before anyone would move forward.
Legal Due Diligence
Legal diligence covers entity records, contracts, litigation history, liens, intellectual property ownership, and employment matters. One of the most overlooked risks is the change-of-control clause buried inside a major contract, which can let a customer or vendor terminate the agreement the moment ownership changes hands. A specialty food producer lost most of its negotiating leverage when the buyer's attorney discovered that its largest distribution contract, representing nearly half of revenue, contained exactly that clause, and nobody at the company had ever read it closely. Any question about contract assignability, litigation exposure, or entity structure belongs with a transaction attorney, not a guess.
Operational Due Diligence
Operational diligence asks whether the business can actually run the way it appears to on paper. Buyers look at customer concentration, dependency on a small number of vendors, the condition of equipment, the systems you use to run the business, and whether your processes are documented or exist only in your head. A business that looks efficient because the owner personally handles every exception worries a buyer far more than one with clear, written procedures a new manager could follow.
Customer and Market Due Diligence
At some point, most buyers want to talk to your customers directly, and this is usually the most sensitive part of the whole process. Customer calls happen late in diligence, after the buyer is already committed enough that the risk of a leak is worth taking, and they run through a short, controlled list of contacts that you and your advisor approve in advance. The framing matters: customers hear that the company is exploring a transition or new investment, not an open invitation to speculate. Done carefully, these calls confirm relationship strength and calm buyer anxiety. Done carelessly, they leak the sale to your competitors and unsettle your best accounts.
Employee and HR Due Diligence
Buyers review how your workers are classified, whether you have key employees whose departure would hurt the business, what you pay relative to market, and whether your management team is likely to stay after closing. A business that depends on one unlicensed lead technician or one salesperson who owns every customer relationship carries real key person risk, and buyers will either discount for it or ask you to lock that person into a retention agreement before closing.
Environmental, Real Estate, Insurance, and Regulatory Due Diligence
Where they apply, these categories get their own specialists. A business with a manufacturing facility, fuel storage, or a history of chemical use may need an environmental assessment. A business that owns real estate or holds a long-term lease will have that lease or deed reviewed independently. Insurance coverage gets checked for gaps and claims history, and any licensed trade, from HVAC to food production to medical, gets checked against your state's actual regulatory requirements.
04 · Process
A Realistic 60-Day Due Diligence Timeline
Most articles stop at listing documents. Almost none of them tell you how the weeks actually unfold, so here is the typical shape of a 60-day period.
Weeks one and two are document production. You and your advisor load financials, tax returns, contracts, and corporate records into a data room, and the buyer's team starts its initial read.
Weeks three and four bring the first real questions, mostly financial. This is when the quality of earnings firm reconciles your numbers and produces its first list of discrepancies or clarifications, and it is usually the busiest stretch for you personally.
Weeks five and six shift toward legal, operational, and customer-facing work. Contracts get reviewed for assignability, site visits happen, and the buyer's attorney starts drafting the purchase agreement in parallel.
Weeks seven and eight are where issues get resolved or a deal gets renegotiated. Customer calls typically happen late in this window, working capital gets finalized, and any retrade conversation usually surfaces here, once the buyer has enough information to justify a number.
By week eight or nine, if things have gone well, you are into final purchase agreement negotiation and scheduling a closing date. Complex businesses, or ones with real estate, franchise approval, or SBA financing involved, often run closer to 90 days.
05 · Perspective
Your Job as the Seller During Due Diligence
Your real job during diligence is to respond fast, tell the truth, and keep the business performing. Slow answers read as evasion even when they are just disorganization, so treat every information request like it has a deadline, because it effectively does. Buyers get nervous the longer diligence drags.
If you know about a problem, whether it is a customer about to leave, a pending lawsuit, or a maintenance issue, disclose it yourself before the buyer's team finds it. A disclosed problem is a negotiating point. A discovered problem is a trust problem, and trust is hard to rebuild mid-deal. Meanwhile, do not let the business slip. Revenue that dips during diligence gets noticed immediately and can trigger a retrade or a walk.
06 · Buyer View
Retrades: When a Buyer Tries to Lower the Price
A retrade is when a buyer reduces their offer, or changes the terms, after diligence has started and often after the LOI has already set a price. It is one of the most emotionally difficult moments in a sale, and it happens more often than most first-time sellers expect.
Some retrades are legitimate. If the quality of earnings review finds that your reported SDE was overstated, because an add-back does not hold up or revenue was recognized incorrectly, the buyer has a real basis for asking to adjust price. If a customer call reveals that a key account plans to leave, that is new information the buyer could not have known at LOI, and an adjustment tied directly to that finding is defensible. Working capital shortfalls uncovered during the true-up process are also legitimate, mechanical adjustments rather than tactics.
Other retrades are tactics, not corrections. A buyer who waits until the final two weeks of exclusivity, when you have turned down other conversations and hold the least leverage, then drops the price citing vague "market conditions" or a re-reading of numbers that have not actually changed, is testing whether you will cave under time pressure. The tell is usually timing and vagueness: a legitimate retrade points to a specific, documented finding, while a tactical one shows up late and stays fuzzy on the reason.
How you respond depends on which kind you are facing. For a legitimate retrade, negotiate the adjustment on its merits, ideally with your CPA or advisor quantifying the actual dollar impact of what was found, rather than accepting the buyer's number at face value. For a tactical retrade, the strongest response is often to hold your price and be willing to let exclusivity lapse. Buyers who are bluffing tend to fold when a seller does not panic, and buyers who are not bluffing will at least have to justify their number with something concrete. Either way, having a backup buyer somewhere in your pipeline, even a soft one, changes your leverage completely.
07 · Fundamentals
Why Deals Die in Due Diligence
Deals rarely die from one catastrophic discovery. They die from small trust failures piling up: a slow response, an evasive answer, a number that never reconciles. Buyers who feel like they are chasing you for information start to wonder what else you might be hiding, and that suspicion compounds faster than any single financial issue would.
The businesses that sail through are usually the ones where the seller already knows what the buyer is going to find, because they looked first. A commercial cleaning company we advised on ran its own sell-side diligence before going to market, cleaning up its books and reconciling every add-back in advance, and it closed in under 45 days with no retrade at all. Preventing a dead deal mostly comes down to preparation before the LOI is signed, not damage control afterward.
08 · Buyer View
Reverse Due Diligence: Investigating the Buyer
Diligence is not one-directional, and if any part of your payment is deferred, you should be investigating the buyer just as hard as they are investigating you.
If you are carrying a seller note, understand the buyer's other debt obligations, their industry experience, and their track record running similar businesses, since you are effectively extending them credit. If you have an earnout tied to future performance, look closely at how much operational control you keep versus how much shifts to the buyer, because a structure that lets the buyer make decisions that suppress the metrics you are paid on is a real risk. If you are rolling equity into the new company, ask to see the buyer's financial statements, their existing debt load, and how previous rollover partners have been treated. A transaction attorney can help you request the right information and build protective language into the purchase agreement.
09 · Perspective
Working Capital and the True-Up
Most purchase agreements require you to leave a normal, agreed-upon level of working capital in the business at closing, and that target usually gets negotiated during diligence and finalized through a true-up calculation shortly after. The buyer's team calculates a working capital target based on your historical average. If the actual balance at closing comes in below that target, the difference is deducted from your proceeds; if it comes in above, you may be owed more.
The process is mechanical, but it is also where sellers lose money they did not expect to lose, usually because they did not understand the target being negotiated or let inventory and receivables drift in the months before closing. Your CPA or M&A advisor should model the working capital target early, not wait for the true-up to surface it as a surprise deduction.
10 · Advisor View
Expert Insight: What Experienced Advisors See in Due Diligence
The sellers who get through diligence cleanest are rarely the ones with the cleanest businesses. They are the ones who stop treating diligence as an interrogation and start treating it as a joint project to get the deal closed. Owners who get defensive, slow-walk requests, or negotiate every information request as if it were a concession tend to create the exact suspicion that produces retrades and dead deals. The owners who hand over what is asked, flag their own weak spots before anyone finds them, and stay focused on running the business instead of managing the process consistently get better outcomes, even when their underlying numbers are not perfect.
Tax and legal questions that come up during diligence, from entity structure to contract assignability to how a retrade might affect your net proceeds, should go to a CPA or transaction attorney who can look at your actual documents. This article explains the concepts; it is not a substitute for that review.
— Expert insight · John Rojas, Wagner Realty Commercial
11 · Q&A
People Also Ask
How long does due diligence take when selling a business?
Most due diligence periods run 30 to 90 days, with 60 days being a common target for a straightforward small business sale. Complex deals involving real estate, franchise approval, or SBA financing tend to run longer.
What documents do buyers request during due diligence?
Buyers typically request three to five years of tax returns and financial statements, bank statements, customer and vendor contracts, corporate and entity records, lease agreements, employee records, and insurance policies. The exact list depends on your industry and business size.
Can a buyer back out during due diligence?
Yes. Most letters of intent are non-binding on price and give the buyer an exit if diligence reveals something material that was not disclosed. This is one of the main reasons early, honest disclosure protects you more than it exposes you.
What is a quality of earnings report?
A quality of earnings report is an independent analysis, usually performed by an accounting firm on the buyer's behalf, that normalizes your financials to show true, recurring cash flow. It strips out one-time events, tests your add-backs, and gives the buyer confidence in the number they are paying a multiple on.
Do I need a lawyer during due diligence?
Yes. A transaction attorney should review the purchase agreement, any disclosure schedules, and the legal findings from the buyer's side before you sign anything binding. This is not a place to rely on a general practice attorney unfamiliar with M&A deals.
What is the difference between due diligence and the letter of intent?
The letter of intent sets the price, structure, and key terms based on preliminary information and opens the diligence period. Due diligence is the verification process that follows, where the buyer confirms those terms are supported by evidence before the deal becomes final and binding.
How do I prepare for due diligence before listing my business?
Reconcile your financials, gather three to five years of clean records, review your major contracts for assignability issues, and address any obvious problems before a buyer finds them. Owners who do this sell-side preparation tend to move through diligence faster and with fewer price adjustments.
What happens if due diligence uncovers a problem?
It depends on the size and nature of the problem. Minor issues usually get resolved through a price adjustment, an escrow holdback, or a specific representation in the purchase agreement, while major undisclosed problems can cause a buyer to walk away entirely.
12 · Pitfalls
Common Mistakes Business Owners Make During Due Diligence
- Waiting until diligence starts to organize financial records. Scrambling to reconcile three years of books while a quality of earnings firm is actively reviewing them signals disorganization at best and raises real suspicion at worst.
- Being defensive or slow to respond to information requests. Every delay reads as evasion to a buyer's team, even when the real cause is simply being busy running the business.
- Never reading your own contracts for change-of-control clauses. Sellers are routinely surprised by language in their own agreements that a buyer's attorney finds in the first week of legal review.
- Letting business performance slip during the diligence window. A dip in revenue or a missed customer commitment during diligence gets noticed immediately and often triggers a retrade.
- Accepting a retrade without asking for the specific finding behind it. A legitimate price adjustment should point to a documented issue. If a buyer cannot name one, that is information too.
- Skipping reverse diligence on a buyer offering a seller note or earnout. Sellers who investigate only the sale price and ignore the buyer's financial stability often discover problems only after money is already owed to them.
13 · FAQ
Frequently Asked Questions
Who pays for due diligence costs?
Each side typically pays for its own advisors. The buyer covers their accountant, attorney, and any specialists, while you cover your CPA and transaction attorney, and these costs should be budgeted for regardless of whether the deal closes.
What does exclusivity mean during the due diligence period?
Exclusivity means you agree not to negotiate with, or accept offers from, other potential buyers while the current buyer conducts diligence. It protects the buyer's investment of time and money, and it is one reason picking the right buyer before signing the LOI matters so much.
Can I still run my business normally during due diligence?
You should run it exactly as normally as possible. Diligence creates real demands on your time, but a business that performs consistently through the process reassures buyers far more than one that visibly slows down while the owner is distracted.
What happens if diligence takes longer than expected?
Extended diligence usually means either the business is more complex than initially understood or the buyer's team found something requiring further review. Occasional extensions are normal, but a diligence period that keeps sliding without clear reasons is worth discussing candidly with your advisor.
Is due diligence the same for an asset sale and a stock sale?
The core categories are similar, but a stock sale typically involves deeper legal review since the buyer is acquiring the entity itself, including its full history of liabilities. Your transaction attorney can walk you through how deal structure changes what gets scrutinized.
What should I do if I discover my own problem during diligence?
Disclose it immediately to your advisor and, in most cases, to the buyer directly. Problems you surface yourself are almost always easier to resolve than problems the buyer's team finds independently, because your credibility stays intact.
How many buyers typically go through due diligence before a deal closes?
Most sellers work with one buyer in exclusive diligence at a time, though it is common for a deal to fall apart and go back to a second buyer from the original pipeline. This is part of why keeping other qualified buyers warm during negotiations matters.
What happens right after due diligence is complete?
Once diligence wraps and any remaining issues are resolved, the parties move to finalize the purchase agreement, satisfy any remaining lender conditions, and schedule a closing date. Funds typically transfer, and ownership changes hands, at closing.
Ready to Move Through Due Diligence With Confidence?
Due diligence is where deals either get confirmed or come apart, and most owners go through it exactly once. Having an experienced advisor beside you, someone who has seen hundreds of these reviews and knows the difference between a routine question and a real problem, changes how the entire period feels.
Preparation before you ever sign a letter of intent is what makes diligence manageable. Clean financials, organized contracts, and an honest accounting of your business's weak spots turn a stressful 60 days into a fairly straightforward one.
We work with business owners through every stage of a sale, including the diligence period itself, to keep deals on track and protect the outcome you have worked toward. A confidential conversation now costs you nothing and can save you real money later.
Contact us today to schedule your confidential consultation about preparing for due diligence.