Buying a business
Due Diligence: Essential Steps for Successful Business Transactions
The workstreams of due diligence, who handles each one, and the order that keeps a business purchase on schedule.
By Michael D. Rubin, CEO & Founder · Updated September 2026 · 683 words
Due diligence is the buyer's structured check that a business is what the seller described, covering its finances, legal position, operations, people, assets and risks, carried out after the letter of intent and before the purchase agreement is signed. It confirms the price, shapes the contract and, now and then, stops a deal that should not close.
Good diligence is organized, not endless. It runs in parallel workstreams, each led by the right professional, on a timeline both sides agree to. How long due diligence takes depends mostly on the size of the company and how well the seller prepared. This is also where a buyer's advisors earn their fees: an experienced CPA and attorney know where problems tend to hide in a company of a given size and type.
The main workstreams and who leads them
| Workstream | What gets reviewed | Usually led by |
|---|---|---|
| Financial | Three years of statements and tax returns, bank records, adjusted earnings, receivables, inventory, working capital | Buyer's CPA or a quality of earnings firm |
| Legal | Entity records, contracts, leases, litigation, licenses, permits, ownership of intellectual property | Buyer's transaction attorney |
| Commercial | Customer list and concentration, contract terms, pricing, competitors, supplier relationships | Buyer, sometimes with industry advisers |
| Operational | Equipment age and condition, processes, systems, capacity, maintenance history | Buyer and operations specialists |
| People | Key employees, pay and benefits, turnover, agreements, the owner's role | Buyer, with HR or benefits counsel |
| Environmental | Site history, contamination risk, compliance for regulated operations | Environmental consultant |
Steps that keep diligence on schedule
Organize the request list by the workstreams in the table above. Sharing it early lets the seller's advisor gather documents in parallel rather than answering one question at a time.
- Assemble your attorney, CPA and lender before the letter of intent is signed.
- Send one complete request list at the start instead of a trickle of questions.
- Agree on a secure data room and a calendar with the seller's advisor.
- Review the financials first; they decide whether the rest is worth paying for.
- Keep a running issues list and discuss findings as they come up.
- Tie each finding to the purchase agreement through price, structure, representations or an indemnity.
Areas buyers underestimate
Environmental risk is the classic one. A site with old contamination, asbestos or poor waste handling can carry cleanup costs far out of proportion to the purchase price, and responsibility can follow whoever owns or operates the property. For manufacturers and any business on industrial land, an environmental review is not optional.
Intellectual property is another. Confirm that trademarks, patents, software, domain names and customer data belong to the company and can transfer. Founders sometimes hold them in their own names.
In a manufacturing company, look hard at equipment: age, remaining useful life, maintenance records and what replacing a key machine would cost. Deferred capital spending is a cost the buyer inherits.
When diligence finds something
Findings rarely end deals on their own; how they are handled does. Quantify each issue, estimate what fixing it would cost, and propose a specific remedy: a price adjustment, a holdback of part of the price until the issue is resolved, a special indemnity, or a condition the seller must meet before closing. Sellers respond better to a clear, documented request than to a general sense that the business is worth less. Some findings simply disappear once raised: a missing document turns up, a lien proves to be paid.
Honesty early helps both sides. A seller who discloses a known issue before the LOI keeps control of how it is framed; the same issue found by the buyer later looks like concealment. Our guide to what causes a business sale to fall apart in due diligence covers the patterns.
How MDR & Associates prepares for diligence
When MDR & Associates represents a seller, the financial recast and supporting records are assembled before the company goes to market, so buyers test prepared material instead of waiting for it. A principal of the firm stays involved through diligence and works with both sides' attorneys and CPAs. Buyers can learn how to access the companies we represent on our buyer page.
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Questions owners ask next
Do I need a quality of earnings report?
A quality of earnings report is an accountant's detailed test of whether reported and adjusted earnings are real and repeatable. It is standard in larger acquisitions and many financed deals. For a smaller purchase, your CPA may do a narrower review. Ask your lender what it requires before deciding.
Who pays for due diligence?
The buyer normally pays for its own advisors, reviews and reports, including any environmental work it orders. The seller pays its own attorney and advisor. Because costs build quickly, buyers usually start with the financial review and spend on the other workstreams only once the numbers hold up.