In every business acquisition there is a moment that transactional advisers call "the moment of truth": the start of the due diligence process. It is the point at which price conversations move from being the seller's aspirations to numbers the buyer will defend, adjust or challenge with documentary evidence. Everything that has happened before — the letter of intent, the preliminary meetings, the exchange of indicative information — is prologue. Due diligence is the text.
Understanding how this process is structured — what happens in each phase, in what order, who does what and how long it takes — is as important for the buyer as for the seller. For the buyer, because it defines the timeframe and budget to assign. For the seller, because the quality of their preparation at each phase directly determines the price and the conditions of closing.
This guide describes the five phases of the due diligence process in a standard Spanish mid-market transaction (between €5 million and €50 million enterprise value), with the typical timelines, the deliverables of each phase, and the decision points that separate a transaction that closes from one that is abandoned.
Phase 1: Planning (week 1)
Define the scope before you start
The most costly mistake made in due diligence does not occur during the analysis — it occurs before it begins, when the scope has not been correctly defined. A process that is too broad wastes time and budget on low-risk areas. A process that is too narrow leaves contingencies unidentified that the buyer will discover once the deal is closed, when there is no longer a remedy.
Planning begins with a working session between the buyer and their principal financial adviser to define three things: which types of due diligence will be carried out, what depth of analysis is appropriate for each, and which specific risk areas — identified during the preliminary information phase or in the letter of intent — merit particular attention.
Assemble the team
A full due diligence involves teams from different disciplines who must coordinate. The buyer needs to appoint a process coordinator — normally the principal financial adviser — to manage access to the data room, centralise questions to the seller, and ensure that all teams work to the same deadlines and from the same information base.
The standard team for a mid-market transaction includes:
- Financial adviser (quality of earnings, working capital and net debt analysis)
- Tax adviser (Corporate Income Tax, VAT, withholdings, transfer pricing)
- M&A lawyers (corporate structure, contracts, intellectual property, litigation)
- Employment lawyers (workforce, collective agreement, social security contingencies)
- Optionally: environmental consultancy, IT/cybersecurity specialist
Engagement letters with each adviser — including fees, timeline and scope — must be signed before the data room opens. Starting analysis without a formal engagement is a frequent source of misunderstanding about responsibility and coverage.
Preliminary risk analysis
Before the data room is available, the buyer’s advisory team can — and should — carry out a preliminary risk analysis based on public information: annual accounts filed with the Registro Mercantil (Companies Register), financial databases, press coverage, litigation records from publicly available judicial databases. This preliminary analysis allows risk areas to be identified before the formal process begins, making subsequent analysis more efficient.
Phase 2: Data room (week 2)
What the data room is and why its organisation matters
The data room is the documentary repository in which the seller makes all relevant information available to the buyer. It can be physical (in a supervised room), but in current Spanish practice it is almost always virtual: specialist platforms such as Intralinks, Datasite or Ansarada, or more accessible tools such as SharePoint or Google Drive with access controls.
The choice of platform is not indifferent: in transactions with high-value confidential information — technology, intellectual property, customer data — a specialist platform with granular access controls, activity logs and the ability to restrict downloads is the recommended approach. For smaller transactions, a simpler solution may suffice.
Standard data room structure
A well-organised data room immediately signals competence and preparation to the buyer. A disorganised one — folders with incoherent names, poorly scanned documents, key information absent — creates a negative first impression that conditions the entire subsequent process.
The standard structure for a Spanish company includes:
1. Corporate and constitutional: Articles of association, statutes, minute books, share register, powers of attorney, current Registro Mercantil extracts.
2. Financial: Annual accounts for the last four financial years, audit reports (if applicable), monthly management accounts for the last twelve months, financial projections, debt and working capital schedules.
3. Tax: Corporate Income Tax returns (Modelo 200), VAT annual summaries (Modelo 390) and withholding tax summaries (Modelo 190) for the last four years, current tax compliance certificates from the AEAT and TGSS (the Social Security Treasury), transfer pricing documentation, inspection reports or ongoing proceedings.
4. Legal and contractual: Contracts with the ten principal clients, contracts with the five principal suppliers, lease agreements, finance agreements, litigation schedules, intellectual property registrations.
5. Labour and HR: Full employee census, collective agreement, key management contracts, ERE/ERTE documentation where applicable, social security account status.
6. Operational and commercial: Business model description, client portfolio with historical revenues, pipeline, certifications and licences.
7. Assets and environmental: Property deeds, fixed asset schedules, insurance policies, activity licences, environmental audit where it exists.
A complete data room for a mid-sized company typically contains between 200 and 800 documents. For groups with multiple subsidiaries or complex corporate structures, it may exceed 2,000.
Access controls and the Q&A protocol
Access to the data room must be controlled: individual user permissions, with a log of which documents each person has viewed and when. The seller must also establish a Q&A protocol: questions from the buyer’s teams are channelled through a single point of contact — normally the seller’s adviser — who responds with additional documentation or clarifications. This protocol prevents different members of the seller’s team from giving inconsistent answers to the same question.
Phase 3: Analysis (weeks 3-5)
The fieldwork
This is the most intensive phase of the process and the most variable in duration. Specialist teams access the data room, review available documentation, raise questions through the Q&A protocol and, where agreed, hold working sessions with the target company’s management team (management presentations).
The financial analysis focuses on reconstructing the real EBITDA — adjusted for non-recurring items and for owner-management costs that are not intrinsic to the business — and on determining the real net debt, including liabilities that are not classified as financial debt in the balance sheet. The quality of the financial analysis depends on the quality of the available information: when the seller’s accounts are unaudited or there are discrepancies between accounting records and tax returns, the financial team needs more time to reconcile and verify.
The tax analysis cross-references Corporate Income Tax, VAT and withholding tax returns against the accounting records to identify discrepancies, questionable deductions and undocumented related-party transactions. It is common for the tax analysis to generate questions that only the seller’s regular tax adviser or the company’s management can answer — these exchanges are always channelled through the Q&A protocol.
The legal analysis systematically reviews each client and supplier contract for change-of-control clauses, verifies the Registro Mercantil, identifies ongoing litigation and verifies the ownership of intellectual property assets.
Red flag checklist every due diligence team looks for
Regardless of transaction type, there is a set of warning signs that experienced due diligence teams look for systematically:
- Financial: EBITDA that does not convert to free cash flow; revenues concentrated in a single client; short-term debt increase over the past twelve months without correlation to EBITDA.
- Tax: Significant divergences between accounting profit and taxable base without justification; unused tax losses older than four years without documentation; absence of transfer pricing documentation in groups with related-party transactions.
- Legal: Change-of-control clauses in contracts with clients representing more than 15% of turnover; intellectual property owned personally by the founder; litigation with material amounts at appeal stage.
- Labour: Discrepancies between payroll categories and actual functions; freelancers working exclusively for the business; outstanding social security balances not reflected in the accounts.
- General: Inconsistency between information in the data room and operational data presented in earlier meetings; incomplete or dilatory responses to due diligence questions.
The management presentation
In transactions of a certain size, it is standard practice to arrange one or two working sessions with the target’s management team so that the buyer’s advisers can ask questions directly and evaluate not only the numbers but the quality of the management team. A management presentation is not a sales pitch — it is a working session in which management must be prepared to answer difficult questions about the accounting, key contracts, ongoing litigation and business outlook.
The quality of management’s responses in the presentation is a relevant input for the buyer: the consistency between what management says and what the documentation shows — or the divergences between the two — is valuable information about the level of control the company has over its own situation.
Phase 4: Report (week 6)
Structure of a due diligence report
The due diligence report synthesises all findings from the process and serves as the basis for negotiating the sale and purchase agreement (SPA). It is, together with the SPA itself, the most important document in the transaction.
A well-structured report has four sections:
1. Executive summary. Principal findings classified by area and by their potential impact on price or on the viability of the transaction. This summary is what the CEO and the buyer’s investment committee will read — the technical sections are for the specialist teams. A clear, direct executive summary — without euphemisms about negative findings — is the best indicator of the quality of the adviser who drafted it.
2. Findings by area. Each discipline (financial, tax, legal, labour) presents its findings in the detail necessary for the buyer’s legal team to convert them into contractual clauses. Findings should be classified into three categories: deal-breakers (where they exist), quantifiable contingencies, and lower-impact observations.
3. Quantification of contingencies. For each identified contingency, the report should include an estimate of the economic impact, expressed as a range (minimum to maximum probable) or as an expected value where probability can be reasonably estimated. This quantification is the direct basis for price negotiation.
4. Recommendations. Which warranty or representation clauses are necessary in the SPA to address each contingency, what additional information should be requested before closing, and which conditions precedent are advisable.
Who reads the report and for what purpose
The due diligence report has three audiences with different needs. The buyer and its management need the executive summary to decide whether to proceed, renegotiate or abandon. The buyer’s lawyers need the detailed findings to draft the representations and warranties in the SPA and to determine which indemnification clauses are required. Acquisition finance lenders, where the transaction involves debt financing, need the financial report — and sometimes the tax report — to assess the risk of the transaction they are financing.
Phase 5: Negotiation (weeks 7-8)
How findings become contractual conditions
Due diligence does not end with the report — it ends when the report’s findings have been translated into contractual clauses that appropriately allocate the identified risks between buyer and seller. This phase is the most delicate in the process because each contingency identified in the report is now a negotiating lever.
The standard contractual mechanisms for managing due diligence findings are as follows:
Price adjustment. For contingencies that can be quantified with sufficient certainty, the price is adjusted directly. If the tax due diligence has identified an unregistered tax liability of €300,000, the price is reduced by that amount. This is the cleanest mechanism, but sellers frequently resist direct adjustments and prefer other mechanisms for contingencies where materialisation is uncertain.
Retention or escrow clauses. A portion of the purchase price — typically between 10% and 20% of the total — is retained in a guarantee account (escrow) for a period of 12 to 24 months, available to compensate contingencies that materialise post-closing. This is the preferred mechanism where contingencies are real but their materialisation is uncertain.
Representations and warranties (R&W). The seller declares in the contract that certain facts are true — for example, that there are no ongoing tax inspection proceedings, or that all client contracts are in force and without breach. If any of these declarations proves inaccurate, the seller is liable to indemnify the buyer. The scope of the R&W, their quantitative limits (basket, cap) and their duration are the most common negotiating points in the final stage of any transaction.
Conditions precedent. For contingencies that must be resolved before closing — a pending administrative permit, a change-of-control consent that must be obtained from a key client, the regularisation of an intellectual property title — closing is conditional on that situation being resolved. Conditions precedent introduce uncertainty into the timetable, and sometimes into the price, if closing is delayed beyond what was anticipated.
Deal-breakers. In approximately 15% of M&A transactions in Spain, due diligence identifies contingencies that the buyer cannot accept or manage through price adjustments or warranties: accounting fraud, tax liabilities of material size that had not been declared, litigation threatening the continuity of the business, or legal irregularities that make the transfer unworkable. In these cases, the transaction is abandoned. This is not a failure of the due diligence process — it is precisely the correct result. The cost of identifying a deal-breaker in due diligence — tens of thousands of euros in adviser fees — is incomparably smaller than the cost of discovering it after closing.
Reference timeline: weeks 1-8
| Week | Principal activity | Responsible party |
|---|---|---|
| 1 | Planning, scope definition, signing of engagement letters | Buyer and advisers |
| 2 | Data room opening, initial review of document structure, first Q&A questions | All teams |
| 3-4 | Intensive financial analysis, tax analysis, legal review of key contracts | Financial, tax and legal advisers |
| 4-5 | Labour and environmental analysis, management presentation | Employment lawyers, environmental consultancy, target management |
| 5 | Q&A close-out, final document review, clarification sessions | All teams |
| 6 | Drafting and review of due diligence report | Process coordinator |
| 7 | Presentation of report to buyer, analysis of price impact | Financial adviser and buyer |
| 7-8 | SPA conditions negotiation: price adjustments, R&W, escrow, conditions precedent | Lawyers and advisers on both sides |
This timeline corresponds to a transaction of €5 million to €50 million without exceptional complexities. The factors that most frequently extend the timeline are: an incomplete or disorganised seller data room (adds one to two weeks), a multi-jurisdictional structure (adds two to four weeks per additional jurisdiction), and complex contingencies requiring additional specialist analysis (variable).
For M&A processes with a time-sensitive element — competitive processes with short deadlines, or distressed situations where the seller needs to close quickly — it is possible to compress the process to three weeks if the data room is correctly prepared. Timeline compression has a cost: more resources deployed in parallel and a greater risk of omissions. BMC can mobilise teams within 24 hours for transactions with justified urgency.
Phase 0: the seller’s preparation
The process described above is narrated from the buyer’s perspective. But there is a “phase 0” that belongs to the seller: preparing the company to withstand the buyer’s scrutiny.
Sellers who arrive at the process without preparation — with the minute book out of date, client contracts in oral form, accounting commingled with personal expenses, and their tax position unreviewed — consistently achieve worse negotiating outcomes. The buyer identifies uncertainties and applies what is known as an uncertainty discount: a deduction that compensates for the risk that could not be resolved during due diligence. In mid-market transactions, that discount can represent between 10% and 20% of the initial price.
Optimal preparation requires between six and twelve months of work before the sale process begins. For transactions where the seller wants to maximise the price, investment in preparation is the highest-return expenditure in the entire process.
For a full breakdown of which types of due diligence apply to each area and what checklist each specialist team applies, see the dedicated guide. For cost ranges and how to calibrate the budget, the DD cost guide for Spain provides updated figures for 2026.
At BMC, we coordinate complete due diligence processes from planning through to SPA negotiation. Request an initial meeting to assess the process your transaction requires.
