Critical Due Diligence Steps for Buyers: The Process in Order

Critical due diligence steps for buyers follow a strict sequence: (1) pre-LOI financial screening, (2) signed LOI and mutual NDA, (3) formal document request list, (4) quality-of-earnings and financial verification, (5) operational and team deep dive, (6) legal, contracts, and compliance review, (7) customer and supplier reference calls, (8) risk scoring and final deal structuring, and (9) attorney and CPA sign-off before close. Skip a step or run them out of order and you either miss a landmine or lose the seller by asking for sensitive documents too early. This is the order that closes deals.

Look, I’ve done 300+ deals over 30 years. The buyers who lose money almost always do the same thing — they run due diligence like a scavenger hunt instead of a process. They ask for tax returns before the LOI is signed. They send an attorney in on week one. They call customers before the seller has agreed they can. Every one of those mistakes kills trust or wastes six figures in professional fees on a deal that was never going to close.

Do the steps in order. That’s the whole game.

Here’s the exact sequence I teach inside Dealmaker Academy, in the order I run it on every acquisition.

Step 1: Pre-LOI Financial Screening

Before you sign anything, you validate whether the business is even worth writing an LOI on — using only what a seller will share without a signed NDA: a redacted P&L, revenue trend, and top-line owner earnings. This step takes 60 to 90 minutes and it kills half the deals in your pipeline. That’s the point.

1. Request a 3-year P&L summary and current-year YTD. If they won’t share this, they’re not a real seller yet — walk away or keep courting.
2. Calculate seller’s discretionary earnings (SDE) or EBITDA. Add back owner salary, personal expenses, and one-time items. This is what the business actually throws off.
3. Screen for cash flow positive with DSCR ≥1.5x at your projected debt load. Below 1.5, the bank won’t finance it and you shouldn’t buy it. Non-negotiable.
4. Sanity-check the multiple. If asking price is 5x SDE for a business with owner-dependent operations and one customer at 40%, you have a math problem, not a deal.

Only if the deal clears this screen do you move to Step 2. Roughly 60% of deals I look at never do.

Step 2: Signed LOI and Mutual NDA

The Letter of Intent (non-binding) and mutual NDA are the two documents that unlock everything else — no financial detail, employee names, or customer data moves without them in place. Signing the LOI also gives you exclusivity, usually 60 to 90 days, so the seller stops shopping the deal while you dig in.

1. Draft the LOI with price, structure, exclusivity window, and diligence timeline. Terms over price. A seller-financed structure often gets accepted at a higher headline number than an all-cash offer at 70%.
2. Include a mutual NDA. Not one-way. Mutual protects both sides and signals you’re a professional buyer, not a tire-kicker.
3. Get everything in writing. No verbal promises. If it’s not in the LOI, it doesn’t exist.
4. Confirm exclusivity in the LOI. Without it, you’re spending money on diligence while a competing buyer sneaks in with a better offer.

See how the LOI fits into the acquisition workflow for the exact clauses that matter.

Step 3: Send the Document Request List

Within 48 hours of a signed LOI, the buyer sends a formal document request list — a numbered checklist covering financials, legal, HR, operations, customers, and IT that becomes the master index for the entire diligence phase. A tight list moves fast. A vague one drags for months and gives the seller time to get cold feet.

Six categories to request in a single package:

1. Financial: 3 years of tax returns, 3 years of P&Ls, 3 years of balance sheets, monthly cash flow, aged receivables, aged payables, current bank statements.
2. Legal: Corporate formation docs, all material contracts, current and past litigation, licenses and permits, insurance policies.
3. HR: Org chart, employee census with tenure and comp, key employee agreements, benefits summary, any HR complaints or claims.
4. Operations: Standard operating procedures, equipment list with condition, facility lease, supplier list with terms.
5. Customer and revenue: Top 20 customers by revenue with concentration, contract terms, churn history.
6. IT and IP: Software licenses, domains, trademarks, patents, tech stack, cybersecurity posture.

Use a virtual data room from day one. Don’t accept documents by email — you’ll lose track.

Step 4: Quality of Earnings and Financial Verification

Quality of Earnings (QoE) is the buyer’s third-party financial audit of the target — a CPA verifies the reported earnings are real, sustainable, and free of one-time or non-recurring bumps that inflate the number the seller is using to justify the price. Skipping QoE is the single most expensive mistake first-time buyers make.

1. Hire a QoE-focused CPA firm, not your regular tax accountant. Costs $15k to $50k depending on deal size. It’s the best money you’ll spend.
2. Reconcile tax returns against P&Ls against bank deposits. Three sources should tell the same story. When they don’t, there’s a reason and it’s rarely good.
3. Strip out one-time items and true-up owner add-backs. COVID PPP forgiveness, one-off contracts, personal expenses that aren’t really personal — these get pulled to find real EBITDA.
4. Verify working capital. How much cash does the business need to operate? That number goes into the purchase agreement as the target working capital at close.
5. Confirm cash flow positive with DSCR ≥1.5x on the verified number, not the seller’s number. If verified EBITDA won’t service the debt, restructure the deal or walk.

See how QoE fits with the other acquisition evaluation frameworks.

Step 5: Operational and Team Deep Dive

The operational and team review answers one question: does this business run without the owner, and if not, how much does it cost to fix that? Owner-dependency is the weakness most buyers under-price. Sellers who work 40+ hours in the business are selling you a job, not an investment.

1. Interview key employees under NDA. Ask them what breaks when the owner is on vacation. Their honest answer is your risk map.
2. Walk the facility with someone who knows the industry. Deferred maintenance is invisible on the P&L and expensive in month one of ownership.
3. Test the SOPs. Ask an employee to run a routine process from the documented SOP. If they can’t, the SOPs are theater.
4. Identify key-person risk. Anyone whose exit would tank the business needs a retention agreement before close, not after.
5. Subtract the market cost of the owner’s labor from earnings. If owner works 40 hours a week and a replacement GM costs $120k, that comes out of SDE before you value the deal.

Step 6: Legal, Contracts, and Compliance Review

Legal due diligence is where your attorney reviews every contract, license, lawsuit, regulatory filing, and corporate document for anything that could survive the close and become your problem. Bring the attorney in at Step 6, not Step 1 — running legal review before financial screening burns fees on deals that die.

1. Contract assignability. Do the top customer and supplier contracts transfer to the new owner or terminate on change of control? A no-assignment clause on your largest customer is a deal-killer.
2. Litigation and claims. Current, threatened, and historical. Anything unresolved goes into the indemnification section of the purchase agreement.
3. Compliance and licenses. Every license needed to operate, current status, transferability. Industry-specific rules (health, safety, environmental, professional) can be non-transferable.
4. Employment law exposure. Wage-and-hour claims, misclassified contractors, unpaid overtime — these travel with the business.
5. Tax exposure. Sales tax nexus in states you didn’t know about, payroll tax liability, unpaid quarterly estimates. Your CPA and attorney work this one together.

Ask your attorney what indemnification, escrow, and holdback protections belong in the purchase agreement to cover the risks they surface. This is a legal question — I don’t give legal advice.

Step 7: Customer and Supplier Reference Calls

Customer and supplier calls happen late in diligence — usually week 4 or 5 — because they signal to the market that a sale is in motion and can spook relationships if timed wrong. Get the seller’s written approval for exactly who you’ll contact and what you’ll say before you dial.

1. Top 5 customers by revenue. Ask about relationship stability, satisfaction, renewal likelihood, and any recent complaints. One honest customer call surfaces risks the CIM buried.
2. Top 3 suppliers or vendors. Terms, exclusivity, payment history, and any change-of-control clauses that trigger on sale.
3. Test customer concentration in real time. If the top 3 customers make up 60% of revenue, and one of them tells you their contract is up for review, price that in — or walk.
4. Ask suppliers about the seller’s payment history. A business that stretches payables to 90 days is a business with hidden cash-flow problems.

Step 8: Risk Scoring and Final Deal Structuring

By Step 8, every finding from steps 1 through 7 gets scored, priced, and translated into deal-structure adjustments — reductions to purchase price, seller notes, earnouts, escrows, holdbacks, or reps and warranties. This is where your diligence turns into leverage.

1. Build a findings log with financial impact per item. Each risk gets a dollar number and a mitigation.
2. Reprice or restructure based on findings. A $200k customer concentration risk becomes a $200k reduction, an earnout, or a holdback — not a walkaway if the rest of the deal is solid.
3. Escrow for indemnification. Standard 10-15% of purchase price held for 12-24 months to cover reps and warranties breaches.
4. Consider a seller note. Structuring 20-40% of the price as a seller note keeps the seller aligned during the transition and protects you if hidden problems surface after close.
5. Model best case, base case, and worst case again using verified numbers. If base case doesn’t clear your required return, walk.

Terms over price. Every time.

Step 9: Attorney and CPA Final Sign-Off and Close

The final step is signing the definitive purchase agreement (APA or SPA) with your attorney and CPA aligned on every material term — from allocation of purchase price to indemnification caps to closing conditions. Nothing at close should surprise you. If it does, back up a step.

1. Final purchase agreement review with attorney. Reps and warranties, indemnification, caps, baskets, survival periods, non-competes, non-solicits.
2. Purchase price allocation with CPA. How the price gets allocated across goodwill, equipment, inventory, and non-competes has real tax consequences for both sides.
3. Working capital true-up mechanism confirmed. Everyone knows the target and the settlement process post-close.
4. Closing conditions checklist. Financing in place, third-party consents obtained, key-employee agreements signed, insurance transferred.
5. Fund and close. Wire the money, sign the docs, get the keys, and start day one with a 100-day plan already written.

I’m not an attorney and I’m not a CPA. Never take legal or tax advice from me — that’s what your professionals are for. My job is to teach you the process and make sure you don’t skip a step.

How Long Does the Whole Sequence Take?

From signed LOI to close, a typical small business acquisition runs 60 to 90 days. Bigger or more complex deals can stretch to 120. Anything faster than 45 days and you’re cutting corners. Anything longer than 120 without a specific reason and the deal is drifting — usually a sign the seller is having second thoughts or the buyer is hesitating.

Pre-LOI screening (Step 1) is unlimited — you might look at 50 deals to find one worth an LOI. That’s normal. That’s the numbers game.

Frequently Asked Questions

What is the correct order of due diligence steps in a business acquisition?

The correct order is: pre-LOI financial screening, signed LOI and mutual NDA, formal document request list, Quality of Earnings and financial verification, operational and team deep dive, legal and compliance review, customer and supplier reference calls, risk scoring and deal restructuring, and finally attorney and CPA sign-off at close. Each step gates the next — you don’t request tax returns before the LOI is signed, and you don’t send an attorney in before financial screening confirms the deal is worth pursuing.

What is the very first step of buyer due diligence?

Pre-LOI financial screening. Before you sign anything, request a 3-year P&L summary and current-year YTD from the seller. Calculate seller’s discretionary earnings or EBITDA, screen for cash flow positive with a debt service coverage ratio of at least 1.5x, and sanity-check the multiple. Roughly 60% of deals fail this screen and never get an LOI.

When should I sign the LOI in the due diligence process?

After pre-LOI financial screening clears (Step 1) and before you request detailed financial or operational documents (Step 3). The LOI plus a mutual NDA is the trigger that unlocks the document request list and gives you exclusivity — usually 60 to 90 days — to complete diligence without competing buyers in the mix.

What is Quality of Earnings and why does it come at Step 4?

Quality of Earnings is a third-party CPA audit that verifies the seller’s reported earnings are real, sustainable, and free of one-time items. It comes at Step 4 because it needs the documents you unlock in Step 3 (tax returns, P&Ls, bank statements) and because it’s the most expensive step — you don’t spend $15k to $50k on QoE until steps 1 and 2 confirm the deal is worth it.

When do I call the target’s customers and suppliers?

Step 7 — usually week 4 or 5 of diligence. Customer and supplier calls happen late because they signal to the market that a sale is in motion. Always get the seller’s written approval for exactly who you’ll call and what you’ll say before you dial. Call the top 5 customers by revenue and top 3 suppliers.

Do I need an attorney and a CPA for all steps of due diligence?

No. Bring the CPA in at Step 4 for Quality of Earnings. Bring the attorney in at Step 6 for legal and compliance review. Running legal work at Step 1 or 2 burns fees on deals that die in early screening. But get the final purchase agreement reviewed by both professionals at Step 9 — never sign it without them. Always defer to your attorney and CPA on legal and tax questions.

How long does the full due diligence process take?

From signed LOI to close, a typical small business acquisition runs 60 to 90 days. Complex or larger deals can stretch to 120. Faster than 45 days usually means corners are being cut. Longer than 120 without a specific reason usually means the deal is drifting — the seller is having second thoughts or the buyer is hesitating.

What’s the difference between this step-by-step process and a due diligence checklist?

A checklist tells you what to verify. This process tells you what to verify in what order and why sequence matters. See our due diligence checklist for the item-by-item list you’ll work through inside each step, and the full 4-phase due diligence framework for how the sequence fits into the broader acquisition workflow.

What happens if I skip a step or run them out of order?

Two outcomes, both bad. Skip too early (like asking for tax returns before the LOI) and you kill trust — sellers stop responding. Skip too late (like bringing in the attorney at Step 1) and you burn $10k to $30k in fees on deals that were never going to close. The sequence protects your money and the seller relationship at the same time.

Where can I learn to run this process on live deals?

Dealmaker Academy walks the full 9-step due diligence process on real acquisition targets with Carl Allen and the coaching team. The Protégé Community is where active dealmakers post their diligence findings and get sanity checks from buyers who’ve closed deals in the same categories.

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Next move: run Step 1 on the three deals sitting in your pipeline right now. See how many clear the screen. That’s your real signal on which deals deserve the next 60 days of your life. Book a coaching call to walk through a specific target with the team.