Due diligence checklist

Definition

The DD checklist is what turns a dataroom from a messy storage into a structured dossier. For the buyer it sets scope; for the seller it determines what must be gathered in advance and in what order. The checklist typically arrives in week 1 post-LOI: sometimes earlier if the buyer has mobilised their DD team: and gives the seller 7 to 14 days to upload the first batch into the dataroom.

The eight standard domains each carry their own priority and pitfalls. Corporate (articles, share register, UBO declaration, prior share transfers): typically 10-20 items, fast to deliver, foundational: the buyer cannot sign title R&W without these. Financial (3 to 5 years of accounts, management accounts, balance sheets, cash flows, VAT returns, bank statements): the largest block, 40-80 items, typically requires input from your accountant or CFO. Legal (key contracts, pending disputes, IP ownership, permits, GDPR compliance): 30-50 items, requires legal review per contract to surface commercially sensitive clauses.

Tax (last 5 to 7 years of corporate tax filings, VAT, local taxes, social security, any rulings or appeals): 20-30 items, critical in Belgium given long statute of limitations for tax claims. HR (org chart, top-10 employment contracts, CLAs and sector-agreement context, pension obligations, pending termination files): 20-30 items, with attention to CLA 32bis implications in asset deals. Commercial (top-10 customer contracts, supplier contracts, distributor agreements, marketing materials, customer satisfaction data): 30-50 items, where buy-side DD focuses most on customer-concentration risk evaluation. IT (architecture, security audit, GDPR conformity, key systems, software licences, optionally an external penetration test): 15-25 items, growing in importance and often the domain where seller-side is poorly prepared. Environmental (active permits, any soil contamination history, energy audit, CSRD climate reporting from 2026 onwards): 10-20 items, critical for industrial sectors.

The central seller-side mistake is reactivity: waiting for the checklist and only then hunting documents. We see repeatedly that this adds 4 to 8 weeks of DD time, with attendant risk of deal momentum loss. The alternative: a vendor-due-diligence-style pre-prepared dataroom 8 weeks before formal marketing kick-off: costs 60 to 120 seller-hours but saves 30 to 50% of DD duration and in our experience delivers a 3 to 7% higher final sale price through preserved buyer-side urgency.

Worked example

An Aalst distribution business with €7.5m revenue started without a pre-prepared DD file. The buyer DD checklist arrived day 4 post-LOI with 287 items across eight domains. First batch upload: day 14 (per SPA deadline). Over the next four weeks repeated follow-up questions came in because legal contracts sat in different physical and digital locations and the external accountant responded slowly. Total DD duration: 11 weeks (vs an average 7 for comparable deals). The buyer, a Dutch roll-up platform, completed DD but knocked €185k off the original bid due to two issues discovered during DD (an unpaid environmental fine from 2022 and a late-discovered intercompany receivable). With a pre-prepared checklist both issues would have been in the disclosure letter pre-LOI: no price damage.

When it matters

For sellers thinking 12 months or more ahead of a sale: start DD prep 6 months before targeted marketing. For those currently in LOI phase: build a per-domain timeline and assign internal or external owners per block. Three critical collection points where we see delay every time: (1) pending tax procedures (older files require archive research), (2) HR files of departed key people (often poorly archived), (3) IP ownership proofs for software developed by external consultants (often missing).

Frequently asked

How many items typically sit on a DD checklist for a Benelux mid-market deal?

200 to 500 items for a €5-25m EV deal, spread across eight domains. Smaller deals (below €5m EV) often get a simplified checklist of 80 to 150 items. Mid-market PE acquirers typically use more extensive checklists than strategic buyers: expect 300+ items from PE side.

When should I start DD preparation?

At least 6 months before targeted formal marketing kick-off. For those wanting to deliver a vendor-due-diligence package: 8 months in advance. Less than 3 months of preparation almost always leads to reactive DD with extended duration and higher risk of price damage from late discoveries.

Who in my organisation should deliver what?

CFO or accountant: financial + tax block. Legal advisor: corporate + legal + commercial contract block. HR lead: personnel files + CLA context + pension obligations. IT lead: architecture + security + GDPR. CEO or operations director: commercial customer block + environmental if relevant. Assign responsibilities explicitly with deadlines per block.

What if I can't locate an item on the checklist?

Document the absence explicitly rather than skipping it. A written note ("this document was lost in 2019 relocation, reconstruction via xyz available") is received far more positively by buyers than silence. Silence triggers repeated questions and distrust: both negative for final price.