Business acquisition
Business Acquisition Due Diligence Checklist [2026]
Buying a business is the fastest way to become a business owner — but one missed red flag can turn a $500K investment into $0. This checklist walks through every document to review, every question to ask, and every red flag that kills a deal.
SDE vs EBITDA — Normalizing the Seller's Financials
The single most important step in due diligence is understanding what the business actually earns. Sellers present “adjusted” numbers. Your job is to verify them. Here's how SDE and EBITDA differ and why normalizing matters.
| Metric | Formula | What It Tells You |
|---|---|---|
| SDE | Net Income + Owner's Salary + Owner's Personal Expenses + Non-Recurring Expenses + Depreciation + Interest | Total financial benefit the owner receives — the starting point for valuation |
| EBITDA | SDE − Owner's compensation at market rate | Earnings available to a new owner who pays themselves a market salary |
The seller runs personal expenses through the business — car lease, health insurance, cell phone, travel, meals. These are called “add-backs.” Many sellers OVER-add-back. You must verify every single add-back independently.
Example: Add-Back Verification
P&L shows $80K net income. Seller claims $40K in add-backs = $120K SDE. You verify: $30K legitimate (documented owner expenses, one-time legal fees), $10K questionable (vague “miscellaneous” entries, no receipts). Your adjusted SDE = $110K — not $120K. That $10K difference, at a 3x multiple, changes the valuation by $30,000.
Red flag:Add-backs exceed 15–20% of revenue — the seller may be inflating earnings. This directly connects to the business-valuation-calculator — use SDE, not net income, to value the business.
Financial Due Diligence Checklist
These 8 documents are non-negotiable. If the seller refuses to provide any of them, treat that refusal as a red flag. Real numbers leave a paper trail — if the paper trail doesn't exist, the numbers may not either.
3 years of business tax returns
Not just P&Ls — tax returns are harder to fake. Cross-reference them with the P&L statements. If the seller won't share tax returns, walk away.
Monthly P&L statements (past 24 months)
Look for declining trends, seasonal patterns, and month-to-month volatility. A single bad quarter might be noise. Six consecutive down months is a signal.
Balance sheets (past 3 years)
Hidden debt and understated liabilities often appear here. Look at retained earnings trends, debt-to-equity, and whether working capital is positive.
Accounts Receivable aging report
How much is over 90 days? Those invoices are probably uncollectible. If 20%+ of A/R is over 90 days, reduce your valuation to reflect likely write-offs.
Accounts Payable aging
Hidden debts. An AP aging report shows bills the business hasn't paid yet. If AP exceeds cash on hand, the business has a liquidity problem.
Bank statements (past 12 months)
Reconcile to P&L — cash doesn't lie. If total deposits don't match reported revenue within 5–10%, investigate the gap.
Sales tax returns
Cross-reference with reported revenue. If the seller under-reported revenue to the IRS, that's tax fraud exposure for YOU as the new owner.
Customer list with revenue per customer
Critical for assessing customer concentration risk. If any single customer represents more than 15% of revenue, that's a red flag.
Customer & Revenue Analysis
Revenue is revenue, right? Not exactly. The quality and composition of revenue dramatically affects business value. Here are the four dimensions to analyze.
Customer Concentration
Any single customer over 15% of revenue is a RED FLAG. That customer leaves, and revenue drops 15% overnight. Target: no single customer over 10%. If concentration exists, negotiate the purchase price down or structure an earn-out tied to customer retention.
Recurring vs One-Time Revenue
Recurring revenue is worth 3–5x more in valuation than one-time project revenue. A business with 80% recurring revenue is far more predictable and valuable than one with 80% one-time projects. Expect lower valuation multiples for project-dependent businesses.
Revenue Trend
Is revenue growing, flat, or declining? A flat business is worth less than a growing one at the same profit level. A declining business is worth significantly less — regardless of how profitable it is today. Look at at least 24 months of monthly data to identify the true trend.
Churn Rate
For subscription/retainer businesses: annual churn over 20% means the business is losing customers faster than it can grow organically. You'll need to invest heavily in acquisition just to stay flat. Factor this into your valuation.
Legal & Compliance Due Diligence
Financials tell you what the business earns. Legal due diligence tells you what you're actually buying — and what liabilities you might inherit. Don't skip this step.
- Entity documents: Articles of incorporation, operating agreement, EIN confirmation letter, good standing certificate. Verify the entity exists and is in good standing.
- Contracts:Review all client contracts, vendor agreements, leases, loans, and employment agreements. Some contracts may not survive a change in ownership — check for change-of-control clauses.
- Lease transfer:The landlord must consent in writing to assign the lease to you. Without written consent, you could be evicted immediately after purchase. This is one of the most common deal-killers — start the conversation with the landlord early.
- Litigation:Any pending or threatened lawsuits? Even “baseless” lawsuits cost money to defend. Review court dockets in the business's county and federal district.
- Intellectual property:Who owns the business name, logo, domain, software code? If the seller's cousin “informally” built the website, you don't own it — and you can't buy what isn't properly assigned. Verify trademark registrations, domain ownership, and written IP assignments.
- Licenses & permits:Can they be transferred to you? Many professional licenses (healthcare, construction, liquor licenses) are non-transferrable. If the business requires a license you can't obtain, you can't legally operate it.
Red Flags That Kill Deals
Some issues can be negotiated. These seven cannot. If you see any of these red flags, strongly consider walking away — or at minimum, demand a significant price reduction and structural protections.
Seller refuses to provide tax returns (only provides P&Ls)
Potential tax fraud or inflated revenue. Tax returns are filed under penalty of perjury. P&Ls are not. No tax returns = no deal.
Revenue spike in the 3 months before listing
The seller might be pulling forward future sales or running one-time promotions. Request 12-month trailing averages to smooth out spikes.
Key employee who plans to leave after sale
Their knowledge and relationships walk out the door. Require retention agreements as a condition of closing, or reduce your valuation to reflect replacement cost.
Seller insists on all-cash deal (no seller financing)
This may mean the seller doesn't believe in the business's future. Seller financing aligns interests — the seller has skin in the game for your success.
Customer concentration over 25%
Single point of failure. If Nordstrom is 30% of revenue and switches vendors, your business loses 30% of revenue. Structure an earn-out or walk.
Unpaid payroll taxes
The IRS can come after YOU as the new owner for the business's unpaid trust fund taxes — even in an asset purchase. This is not dischargeable in bankruptcy. Verify payroll tax compliance absolutely.
Industry in structural decline
Great financials in a declining industry often mean the seller wants out before the crash. Research industry trends independently — don't rely on the seller's narrative.
Run the Numbers Before You Sign
Use our business valuation calculator to estimate what the business is worth based on normalized SDE, and our loan repayment calculator to model your acquisition financing.
Frequently Asked Questions
How do I verify that the seller's revenue is real?▼
Cross-check: (1) Tax returns vs P&L. (2) Bank statements — total deposits should match reported revenue within 5–10%. (3) Sales tax returns — reported sales should be consistent. (4) If cash-heavy business (restaurant, retail, salon), observe the business for 1–2 weeks and count customers/tickets. Cash businesses are the hardest to verify — apply a 10–20% “haircut” to seller's claimed revenue for cash businesses.
Should I buy the assets or the stock/equity?▼
Asset purchase: buy the assets (equipment, inventory, customer list, name) but not the entity. You avoid inheriting the seller's liabilities. Stock purchase: buy the entire entity. Simpler for continuing contracts, but you inherit all liabilities (known and unknown). Most small business acquisitions are asset purchases for liability protection.
How do I structure seller financing?▼
Typical: 60–80% cash at closing, 20–40% seller note over 3–5 years at 5–7% interest. Seller financing aligns the seller's interests with yours — they want the business to succeed so you can pay them. If the seller refuses any financing, negotiate a lower purchase price to reflect your higher risk.
What's a Letter of Intent (LOI) and when do I need one?▼
LOI outlines the proposed deal terms before you spend money on due diligence. It's typically non-binding except for exclusivity (seller can't shop the deal to others during due diligence) and confidentiality. Don't start expensive due diligence (lawyer, CPA) without a signed LOI — you don't want to spend $10K on due diligence only for the seller to accept a better offer.
How do I value a business for acquisition?▼
Three methods: (1) SDE multiple — 2–3x for businesses under $1M SDE, 3–4x for $1M–$5M. (2) Asset-based — value of equipment + inventory + customer list. (3) DCF (Discounted Cash Flow) — present value of projected future cash flows. For small businesses under $5M revenue, SDE multiple is the most common. Use our business-valuation-calculator to run the numbers.