The short answer: Buyer due diligence runs in five steps, (1) verify the financials, (2) confirm legal and corporate standing, (3) test customers and contracts, (4) review operations, people, and assets, then (5) make the go/no-go call. Budget 30 to 60 days, run it alongside SBA underwriting, and pull our downloadable checklist so nothing slips. If something material breaks, renegotiate, add protections in the purchase agreement, or walk.
What diligence is for
Once your LOI is signed and you have exclusivity, diligence begins. The goal isn't to find a perfect business, none exist, it's to find every material issue before you're contractually committed, and to make sure the number you agreed to still holds once you've seen the real books.
Diligence isn't about trusting the seller less. It's about needing to trust them at all.
The five-step process
Work these in order. The financial step gates the rest, if the earnings aren't real, nothing else matters.
Step 1, Verify the financials
Reconcile what the seller presented against source documents. You're confirming the earnings you're paying a multiple on are real.
- 3 years of federal tax returns, the anchor; everything reconciles to these.
- 3 years of P&Ls and balance sheets, plus year-to-date.
- Bank statements to match deposits against reported revenue.
- The add-back / SDE schedule, challenge every add-back for legitimacy.
- A/R and A/P aging, merchant/POS reports, and sales-tax filings.
If the numbers don't reconcile, stop
If three years of returns and financials don't tie out, that's not a diligence gap, it's a signal of poor records or concealment. Both are reasons to demand structural protections or walk. See due diligence red flags.
Step 2, Legal & corporate
- Entity documents, cap table, and good-standing certificates.
- All licenses and permits, and whether they transfer to you.
- UCC lien searches and any tax liens or judgments.
- Litigation, past, pending, and threatened.
- Insurance policies and loss history.
Step 3, Customers, contracts & revenue quality
- Customer concentration, flag any client over ~20% of revenue.
- Top customer and supplier contracts, and their change-of-control clauses.
- Recurring vs one-time revenue, churn, and pipeline.
- How much revenue depends on the owner's personal relationships.
Step 4, Operations, people & assets
- Employee roster, comp, key-person risk, and who might leave.
- The lease and, critically, landlord consent to assign it.
- Equipment condition, deferred maintenance, and inventory count.
- Systems, software, domains, and standard operating procedures.
Step 5, The go / no-go decision
Now weigh what you found against the price. Every finding lands in one of three buckets:
| Finding | Response |
|---|---|
| Value is lower than represented | Renegotiate price or structure |
| Specific, quantifiable risk (e.g. a disputed tax bill) | Protect, escrow holdback or indemnity in the APA |
| Fraud, unverifiable earnings, or a fatal liability | Walk, see red flags |
Print-and-use request list
Here's a condensed version to send with your first diligence request. The full, categorized version is in our template.
- ☐ 3 yrs tax returns + YTD financials
- ☐ Bank statements (12 months)
- ☐ Add-back / SDE schedule with support
- ☐ A/R + A/P aging
- ☐ Customer list with revenue by account
- ☐ Top customer & supplier contracts
- ☐ Lease + estoppel / landlord consent
- ☐ Employee roster, comp, org chart
- ☐ Licenses, permits, insurance
- ☐ UCC / lien / litigation search results
- ☐ Equipment list & inventory
Get the full diligence checklist
Every request above, categorized and ready to send, plus a QoE decision guide.
Frequently asked questions
For a small business, usually 30 to 60 days, running in parallel with SBA underwriting. Your LOI's exclusivity period should cover diligence and closing, typically 60 to 90 days.
Financial (verifying earnings and add-backs), legal/corporate (entity, licenses, litigation, liens), commercial (customers, contracts, revenue quality), and operational (staff, lease, equipment, suppliers). Larger deals add tax, environmental, and IT diligence.
Yes. At minimum, have a CPA reconcile the tax returns against the financials and review the add-backs. On larger or messier deals, buyers commission a Quality of Earnings report.
Renegotiate price or terms, add protections in the purchase agreement (escrow holdbacks, specific indemnities), or walk. Because the LOI's economic terms are non-binding and conditioned on satisfactory diligence, you can usually exit if a deal-killer surfaces.
Sources
- Due diligence process, areas, and timelines, Acquisition Stars M&A diligence guide (2025 to 2026).
- Financial reconciliation and record-quality signals, Acquidex.
