Due diligence
The buyer's post-LOI investigation of the business, covering financial, legal, commercial, tax, and operational matters.
Also called: DD · Diligence
Diligence is where a buyer tests everything they were told. Financial diligence reconciles the reported earnings to bank statements and tax filings and re-examines every add-back. Legal diligence reads the contracts, the leases, the corporate records, the litigation history, and the employment arrangements. Commercial diligence talks to the market about customer concentration, churn, competition, and pricing power. Operational and IT diligence look at systems, dependencies, and key-person risk.
For a seller it is the most demanding phase of the process. Requests arrive in batches, they arrive while the business still has to be run, and the quality and speed of the answers materially affect the outcome — not because a buyer expects perfection, but because disorganisation reads as risk, and risk gets priced.
The single most useful preparation is to run the buyer's checklist on yourself before you go to market. Every problem you find first is a problem you can fix, explain, or price in. Every problem the buyer finds first is a re-trade conversation you are having from a weaker position, halfway through an exclusivity period.
Where sellers get caught
- Discovering your own problems during the buyer's process rather than before it.
- Slow, partial answers. Momentum is an asset, and it decays.
- Letting diligence expand without limit. Agree scope and a timeline in the LOI.
- Answering informally in email what should be answered once, properly, in the data room.
Common questions
How long does due diligence take?
It varies with deal size, structure, financing, and how prepared the seller is. Small owner-operator deals move faster than institutional ones. Preparation is the variable you control.
Can a buyer reduce the price during diligence?
They can try, and a re-trade is a real risk once you are in exclusivity. The defences are preparing thoroughly, keeping the exclusivity period tight, and having a credible alternative.
Related terms
Quality of earnings
An independent accounting analysis that tests whether reported earnings are real, recurring, and sustainable.
Data room
The controlled repository where diligence documents are shared with a buyer, with permissions and an access log.
Letter of intent
A mostly non-binding document setting out the proposed price, structure, and process, whose binding provisions typically cover exclusivity and confidentiality.
Representations and warranties
Statements of fact about the business made by the seller in the purchase agreement, which the buyer relies on and can claim against if untrue.
Guides that use this term
Where due diligence comes up in a real sale, and what it changes.
Last reviewed 2026-08-25. General information for business owners, not legal, tax, or financial advice — terms, thresholds, and tax treatment vary by jurisdiction and by deal.