When a buyer signs a letter of intent, the next email you receive is a due diligence request list. Sellers who have the documents ready close faster and defend their price better, because every delay and every surprise gives the buyer a reason to retrade.
This checklist covers what buyers of main-street and lower-middle-market businesses actually request. Use it before going to market: assembling these documents early is the single highest-leverage preparation step in a sale.
Financial documents
- Three years of financial statements (P&L, balance sheet, cash flow)
- Three years of business and, for smaller deals, owner tax returns
- Year-to-date financials with prior-year comparison
- Accounts receivable and payable aging reports
- Revenue by customer, product, and month for seller's discretionary earnings analysis
- Add-back schedule documenting owner compensation and one-time expenses
- Existing debt schedule with payoff amounts and prepayment terms
Legal and corporate records
- Formation documents, operating agreement or bylaws, ownership records
- Good standing certificates and business licenses
- Material contracts: customers, suppliers, distributors, franchisors
- Real estate leases or deeds, including assignment and change-of-control clauses
- Intellectual property: trademarks, patents, domain names, trade secrets
- Pending or historical litigation, judgments, and settlement agreements
- Insurance policies and claims history
Operations and employees
- Organization chart with roles, tenure, and compensation
- Employment agreements, non-competes, and contractor arrangements
- Benefit plans and any accrued liabilities
- Standard operating procedures and key process documentation
- Equipment lists with ownership or lease status
- Supplier concentration analysis and key vendor terms
Customers and revenue quality
Buyers pay for revenue that survives the transition. Expect intense focus on customer concentration, contract transferability, and any relationships that depend personally on the owner.
Prepare a customer concentration table showing the top ten customers' share of revenue over three years, plus churn or repeat-purchase data if your model supports it. If any customer exceeds 15 to 20 percent of revenue, be ready to discuss the relationship's depth beyond the owner.
Organizing the checklist into a data room
Structure your room to mirror this checklist: one top-level folder per section, numbered to match the buyer's request list, so every response to a diligence question is a link rather than an attachment.
Stage access in tiers. Early buyers see summary financials and the confidential information memorandum; only buyers under a signed LOI see customer names, contracts, and employee detail. A room with per-buyer permissions and watermarking, like Papermark, lets you run multiple interested buyers in parallel without them ever seeing each other.
Next steps
FAQ
How long does due diligence take when selling a business?
Typically 30 to 90 days from LOI for main-street and lower-middle-market deals. Sellers with organized data rooms consistently land at the short end of that range.
What do buyers look at first in diligence?
Financial verification: reconciling the P&L against tax returns and bank statements. Discrepancies found here color everything that follows, which is why the financial folder should be airtight before going to market.
Should I share customer names before closing?
Usually only late in diligence, under NDA, and often anonymized until the final stage. Customer lists are among the most damaging documents to leak if a deal falls through.
Who should assemble the diligence documents?
The owner with their accountant and attorney, ideally before the business is listed. Brokers report that deals with pre-built data rooms close meaningfully faster and with fewer price renegotiations.