Due Diligence Checklist for Prospective Buyers: The 6-Section List I Take Into Every Deal

A due diligence checklist for prospective buyers is a printable, section-by-section list of the documents, numbers, and interviews required to verify a target business before you sign a purchase agreement. Used well, it covers six areas — financial records, legal documents, operations, customer and revenue verification, systems and IT, and red flags — with roughly 60-80 line items in total. Every item either confirms the seller’s story or exposes a gap you must price into the offer, escrow, or walk away from.

Look, I’ve closed 300+ deals over 30 years. Every one of them lived or died on the checklist. Skip a line item, and it turns up six months after close as a lawsuit, a tax bill, or a customer who quietly walks. This is the exact list I hand my team on day one of any acquisition.

Print it. Take it to the meeting. Tick the boxes. This is the same framework we teach inside Dealmaker Academy, and it pairs with the 4-phase workflow in our due diligence hub.

Quick note before we start: your CPA verifies the numbers, your attorney verifies the contracts. This checklist tells you what to collect and what to ask. It does not replace either professional.

Section 1: Financial Documents Checklist

The financial section confirms the earnings you are actually buying. If the seller can’t produce these documents inside 10 business days, that’s a signal on its own. Reconcile every document against the others — tax returns against P&Ls, P&Ls against bank statements, bank statements against deposit slips.

• ☐ 3 years of federal tax returns (business)
• ☐ 3 years of profit and loss statements, month-by-month
• ☐ 3 years of balance sheets
• ☐ 3 years of cash flow statements
• ☐ Trailing 12-month P&L (most recent)
• ☐ Bank statements, last 24 months, all accounts
• ☐ Merchant processor statements, last 24 months
• ☐ Accounts receivable aging report
• ☐ Accounts payable aging report
• ☐ Debt schedule — every loan, line of credit, and lease
• ☐ Sales tax filings and any state/local tax records
• ☐ Payroll register, last 12 months
• ☐ Owner add-back schedule (what runs through the business that shouldn’t)
• ☐ DSCR calculation on your proposed deal structure — must clear 1.5x
• ☐ List of all bank accounts, credit cards, and merchant accounts

Section 2: Legal Documents Checklist

The legal section confirms what you’re inheriting the day you take the keys. Every contract, every lease, every claim. Your attorney runs this section — you make sure nothing on this list is missing from the data room.

• ☐ Articles of incorporation or LLC formation documents
• ☐ Operating agreement or bylaws
• ☐ Cap table and shareholder register
• ☐ All customer contracts (or the top 20 by revenue if there are hundreds)
• ☐ All supplier and vendor contracts
• ☐ Real estate lease(s) and any renewal terms
• ☐ Equipment leases
• ☐ Employment agreements for all W-2 staff
• ☐ Independent contractor agreements
• ☐ Non-compete, non-solicit, and non-disclosure agreements
• ☐ Trademarks, patents, and registered IP
• ☐ Software licenses — SaaS, ERP, everything
• ☐ Domain names, hosting, and technical accounts
• ☐ Any active or threatened litigation, with attorney letters
• ☐ Insurance policies (general liability, E&O, cyber, workers’ comp)
• ☐ Regulatory licenses and permits

Section 3: Operational Checklist

The operational section confirms whether you’re buying a business or a job. If everything lives in the seller’s head, you’re not acquiring an asset — you’re buying yourself 60 hours a week. This section flushes that out.

• ☐ Organization chart with every seat named and dated
• ☐ Owner time-and-role audit — where the seller spends their 40+ hours
• ☐ Documented SOPs for revenue-critical processes
• ☐ Vendor list with terms, credit limits, and lead times
• ☐ Inventory list with cost, location, and turnover
• ☐ Equipment list with age, condition, and replacement cost
• ☐ Deferred maintenance list (walk the shop floor with a vendor)
• ☐ Facilities condition report
• ☐ Production or service capacity vs. current utilization
• ☐ Key-person risk map — who can’t leave without breaking the business
• ☐ Retention agreements or plans for key employees
• ☐ Employee handbook and HR policies
• ☐ Any open workers’ comp or HR claims

Section 4: Customer & Revenue Verification Checklist

The customer section confirms that the revenue you see on the P&L is real, recurring, and not sitting in three fragile accounts. This is where I catch the most surprises. Sellers show you the aggregate; the concentration and the churn hide in the detail.

• ☐ Full customer list, ranked by trailing-12-month revenue
• ☐ Customer concentration report — no single customer over 15% is the target
• ☐ Recurring vs. one-time revenue breakdown
• ☐ Contract length, auto-renewal terms, and change-of-control clauses
• ☐ 3-year customer churn / retention numbers
• ☐ Interviews with the top 5 customers (under NDA if needed)
• ☐ Any handshake deals or side agreements the seller hasn’t put in writing
• ☐ Pricing history — when was the last increase, and by how much
• ☐ Marketing spend and lead sources for the last 12 months
• ☐ CRM export or pipeline snapshot
• ☐ Referral sources and referral partner agreements

Section 5: Systems & IT Checklist

The systems section confirms what you’re inheriting technically — and what you’ll have to rebuild in year one. Old tech is not free. Add modernization cost to your acquisition budget before you agree to a purchase price.

• ☐ List of all software in use, with subscription cost and renewal date
• ☐ Accounting system (QuickBooks, NetSuite, etc.) with admin access confirmed
• ☐ CRM system and export of full contact database
• ☐ Website login, hosting account, and domain registrar access
• ☐ Email accounts, Google Workspace or Microsoft 365 admin
• ☐ Data backup schedule and last successful restore test
• ☐ Cybersecurity posture — MFA, endpoint protection, breach history
• ☐ Hardware inventory (servers, laptops, phones)
• ☐ Any custom-built software or internal tooling — with source code and documentation
• ☐ Third-party integrations and API keys
• ☐ Social media accounts and platform admin transfers

Section 6: Red Flag Watchlist

The red flag section is the walk-away list. Not every item here kills a deal, but two or more from this list and you renegotiate hard or you throw the flag and move on. Deal killers are cheaper to spot in due diligence than to unwind post-close.

• ☐ Discrepancies between tax returns, P&L, and bank statements
• ☐ Cash transactions that don’t reconcile to deposits
• ☐ Unfiled tax returns or open IRS/state notices
• ☐ Pending or threatened litigation the seller “forgot” to mention
• ☐ Criminal history involving the seller
• ☐ One customer above 25% of revenue
• ☐ Key employee threatening to leave at close
• ☐ Refusal to allow customer interviews
• ☐ Seller unwilling to sign a non-compete
• ☐ Deferred maintenance greater than 12 months of free cash flow
• ☐ Owner working 60+ hours with no #2 in the business
• ☐ Revenue trend down two years in a row with no explanation
• ☐ Seller pushing you to skip an LOI or offer letter
• ☐ Verbal-only promises on price, terms, or transition support

How to Use This Checklist on a Live Deal

The list only works if you run it in order. Skip around and you’ll miss the reconciliations that catch the real problems.

1. Send the request list after the LOI is signed. Not before. You don’t do full diligence on tire-kickers.
2. Give the seller 10 business days. If they can’t produce the financial and legal sections in that window, treat that as data.
3. Route each section to the right professional. CPA on financials. Attorney on legal. You (and any operator you trust) on operations, customers, systems, and red flags.
4. Reconcile across sections. The bank statements should match the P&L. The org chart should match payroll. The customer list should match the AR aging.
5. Score red flags before you re-price. Zero red flags: proceed on original terms. One or two: renegotiate price, add escrow, or extend the seller note. Three or more: walk.

Focus on terms over price when you renegotiate. A seller-financed deal at 90% of asking beats an all-cash deal at 70% almost every time — the terms give you the cash flow to cover any surprises the checklist surfaced.

Where This Checklist Sits in the Larger Process

This checklist is the collection layer. It sits inside the 4-phase workflow — preliminary review, financial diligence, legal diligence, operational diligence — that we cover in the due diligence hub. Once you’ve collected everything on this list, you feed it into that framework to decide whether to proceed, renegotiate, or walk.

If a deal is at that stage right now and you want a second set of eyes, that’s what DWS coaching is for. Bring your completed checklist to the call.

Frequently Asked Questions

What should a due diligence checklist for prospective buyers include?

A complete due diligence checklist for prospective buyers covers six sections: financial documents (3 years of tax returns, P&Ls, bank statements, debt schedule), legal documents (contracts, leases, IP, litigation), operations (org chart, SOPs, owner time audit), customer and revenue verification (concentration, churn, top-5 interviews), systems and IT (software, backups, cybersecurity), and a red flag watchlist. Together it runs to roughly 60-80 line items.

How long does buyer due diligence take?

Standard buyer due diligence runs 30 to 60 days from a signed letter of intent. Financial and legal collection should complete inside the first 10 business days, customer interviews and operational review over the following 2-3 weeks, and reconciliation plus red flag scoring in the final week. Larger or more complex deals stretch to 90 days.

Who runs each section of the checklist?

Your CPA runs financial diligence. Your attorney runs legal diligence. You — with any operator or advisor you trust — run operational, customer, systems, and red flag review. Never accept a seller-supplied CPA or attorney as your only reviewer; you need independent counsel on your side of the table.

What documents do you request first?

Start with 3 years of federal tax returns, month-by-month P&Ls for the same period, the trailing 12-month P&L, current AR and AP aging reports, the debt schedule, and the full customer list ranked by revenue. If the seller can produce those inside 10 business days, the rest of the checklist will usually follow. If not, that resistance is data.

What is the biggest red flag in due diligence?

Discrepancies between the tax returns, the P&L, and the bank statements. If the three don’t reconcile, either the numbers are wrong or the seller is showing you a version of the business that doesn’t exist. Every other red flag on the list is manageable through price or terms. That one is a walk-away.

Do you need a lawyer and CPA to run due diligence?

Yes. The checklist tells you what to collect. Your attorney tells you what the contracts and disclosures actually mean, and your CPA tells you whether the numbers hold up under quality-of-earnings review. Both pay for themselves the first time they catch something you would have missed. This article is a process guide, not legal or accounting advice.

What customer concentration is acceptable in an acquisition?

The working rule is no single customer above 15% of revenue. Between 15% and 25% you renegotiate — usually a longer seller note or a customer-retention escrow. Above 25%, treat it as concentration risk and structure an earnout tied to that customer staying past close, or walk.

What is the difference between due diligence and a business valuation?

Due diligence is verification — you’re proving the business is what the seller claims it is. Valuation is pricing — you’re deciding what to pay based on the verified numbers. Diligence comes first. You can’t value what you haven’t verified.

Where can prospective buyers get help running this checklist?

Dealmaker Academy walks the checklist on real acquisition targets alongside Carl Allen and the coaching team. The Protégé Community is where active dealmakers share their diligence findings and get sanity checks from other buyers. DWS coaching is 1-on-1 for a specific live deal.

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Next move: pull up the last deal you’re evaluating, print this checklist, and run every section. Anything you can’t produce a document for in 10 business days becomes a question for the seller — or a reason to renegotiate. When you’re ready to work a real deal end-to-end, start inside Dealmaker Academy or book a coaching call.