Business Acquisition Due Diligence Checklist (2026)

1. Profit & Loss Quality

• Request 36 months of monthly P&L statements, not just annual summaries. Monthly detail exposes seasonality, one-time spikes, and quiet declines that annual numbers hide.
• Confirm whether the books are cash basis or accrual. Cash-basis books can make a declining business look stable for months.
• Check gross margin stability month over month. A margin that drifts down 2 to 3 points per year usually means pricing pressure or rising input costs the seller has not mentioned.
• Separate recurring revenue and expenses from one-time items in both directions: a one-time contract inflates earnings, a one-time lawsuit expense understates them.
• Ask who prepares the books. Owner-kept books need more verification than books maintained by an outside bookkeeper or CPA.

2. Add-Backs and Seller's Discretionary Earnings

• Demand documentation for every add-back. "Owner's discretionary travel: $18,000" should come with the actual credit card statements, not a spreadsheet line.
• Verify the owner salary add-back against what it will really cost to replace the owner. If the owner works 60 hours a week and the add-back assumes a $50,000 manager, the earnings are overstated.
• Look for family members on payroll. Adding back a spouse's salary is only valid if the spouse does no real work; if they run the back office, you are hiring their replacement.
• Check related-party rent. If the seller owns the building and charges the business below-market rent, your post-close rent will be higher and earnings lower.
• Reject "growth adjustments" and projected synergies as add-backs. You are buying the business as it performs today.

3. Revenue Verification

• Tie reported revenue to 12 to 24 months of bank statements. Deposits should reconcile to the P&L within a small margin; large unexplained gaps are a serious problem.
• Pull merchant processor and POS reports directly where possible. These are harder to manipulate than exported spreadsheets.
• Match the P&L to the filed tax returns. If the seller tells you the business earns more than the returns show "because of cash sales," you cannot verify that revenue and should not pay for it.
• Sample real invoices and match them to payments received. Ten random invoices per quarter is a reasonable sample for a small business.
• Watch for revenue pulled forward: unusually aggressive Q4 billing, prepaid annual deals booked as current revenue, or channel stuffing right before the listing date.

4. Accounts Receivable and Accounts Payable

• Get AR and AP aging reports as of the most recent month-end. Receivables over 90 days old are often uncollectible and should be excluded from working capital.
• Check for disputed invoices and credit memos. A pattern of credits to one customer can signal quality problems or an informal discount the P&L does not show.
• Review deferred revenue and customer deposits. If customers have prepaid for work not yet delivered, you inherit that obligation; make sure the purchase agreement accounts for it.
• Confirm payment terms both ways. A business that collects in 60 days and pays suppliers in 15 will eat more of your cash than the P&L suggests.

5. Taxes

• Collect 3 years of federal business tax returns and compare them line by line to the P&Ls you were given.
• Verify payroll tax filings (Form 941) are current. Unpaid payroll taxes create personal liability and can follow the business assets.
• Confirm sales tax registration and remittance in every state where the business has customers. Uncollected sales tax is a common hidden liability in e-commerce deals.
• Review 1099 contractor relationships. Workers treated as contractors who function as employees are a misclassification liability you may inherit.
• Ask directly, in writing, whether there are open audits, notices, or payment plans with the IRS or any state agency.

Contracts and the Lease

Read every material contract for assignability and change-of-control clauses. Many customer contracts, supplier agreements, and franchise agreements require consent to transfer, and the lease is the single most common deal-delayer: landlord consent to assignment can take weeks and sometimes comes with a rent increase. Whether contracts transfer automatically also depends on deal structure, which is covered in our guide to asset sales versus stock sales. In an asset sale, most contracts must be re-signed or formally assigned; in a stock sale, they usually ride along but so do the liabilities.

Licenses and Permits

List every license the business needs to operate: state and local business licenses, professional licenses, health permits, liquor licenses, contractor licenses, DOT authority. For each one, confirm whether it transfers, how long the transfer takes, and whether the buyer must qualify personally. A license that cannot transfer, or that requires a credential you do not hold, is a structural problem to solve before closing, not after.

Litigation, Liens, and Judgments

• Ask the seller to disclose all litigation, threatened claims, and demand letters from the past 5 years, in writing.
• Run independent searches anyway: UCC filings, county court records, federal PACER, and state tax lien databases.
• UCC liens against the assets must be released at closing; your attorney should track payoff letters for every secured creditor.
• Check for OSHA citations, EEOC complaints, and wage claims; employment disputes are common in businesses with hourly staff.

Intellectual Property

• Confirm the business entity, not the owner personally, owns the trademarks, domains, website, and social accounts.
• Verify contractor-created assets (logos, code, content) were assigned in writing; without a work-for-hire clause, the contractor may still own them.
• Check trademark registrations are live and cover the actual products and markets.
• Inventory software and content licenses to confirm they permit transfer to a new owner.

How long does due diligence take when buying a business?

Most small business deals allow 30 to 90 days of due diligence after the letter of intent is signed. Simple asset purchases under $1,000,000 often finish in 30 to 45 days. Larger or licensed businesses (healthcare, government contracting, multi-location) commonly need 60 to 90 days, and SBA lender underwriting frequently runs in parallel and sets the real timeline.

What documents should I request during due diligence?

At minimum: 3 years of monthly profit and loss statements and balance sheets, 3 years of business tax returns, 12 to 24 months of bank and merchant processor statements, AR and AP aging reports, customer revenue by account, all material contracts and the lease, licenses and permits, an employee roster with compensation, and documentation supporting every add-back the seller claims.

What are the biggest red flags in business due diligence?

The deal-stoppers are revenue that cannot be tied to bank deposits or tax returns, a seller who refuses to share tax returns, undisclosed litigation or tax liens, a single customer over roughly 50% of revenue with no contract, and a sudden revenue spike right before the sale that has no operational explanation. Any one of these justifies walking away or repricing the deal.

Do I need an accountant and attorney for small business due diligence?

Yes. A CPA experienced in financial due diligence for small business acquisitions verifies earnings quality, add-backs, and tax exposure, and an attorney reviews contracts, liens, and the purchase agreement. On a typical deal under $5,000,000 this professional help usually costs a fraction of one percent of the purchase price and regularly pays for itself in renegotiated terms or avoided mistakes.

What happens if I find problems during due diligence?

You have four options: renegotiate the price, restructure the deal (for example, shift more of the price to an earnout or holdback escrow), require the seller to fix the issue before closing, or walk away. A well-drafted letter of intent makes diligence findings a valid reason to exit without penalty, which is why you should never sign an LOI that locks you in before diligence is complete.