Due diligence sits at the heart of every business acquisition in Spain, yet fee transparency in this market remains frustratingly limited. Buyers routinely discover either that they have overpaid for generic scope they did not need, or — more expensively — that they underspent and missed contingencies that emerged post-closing. This guide sets out realistic 2026 pricing benchmarks, drawn from mid-market Spanish M&A practice.
What Due Diligence Is — and What It Is Not
Before discussing cost, it is worth being precise about scope. Due diligence is a structured information-review process with three specific objectives: confirming or challenging the valuation assumptions behind the offer price; identifying contingencies — tax, labour, legal — that may affect price or contract terms; and providing the factual basis for the representations and warranties the seller will give in the Share Purchase Agreement (SPA).
Due diligence is not a statutory audit in the sense of the Spanish Audit Law (Real Decreto Legislativo 1/2011). It does not produce an auditor’s opinion. It is not a business valuation, though it generates data that feeds one. And it does not replace legal negotiation of the SPA — it informs it.
That distinction matters for pricing: buyers who confuse DD with audit often overbuy; those who treat it as a rubber stamp often underbuy.
Fee Ranges by Deal Size
The table below reflects standard market pricing in Spain for 2026, covering combined financial-tax-legal scope with a single integrated team. All figures exclude VAT.
| Deal size | Financial + Tax DD | + Legal DD | + Labour DD | Typical total range |
|---|---|---|---|---|
| Under €1M | €1,500–€4,000 | €1,000–€2,500 | €800–€1,500 | €3,000–€8,000 |
| €1M – €5M | €3,000–€7,000 | €2,000–€5,000 | €1,500–€3,000 | €6,000–€15,000 |
| €5M – €20M | €6,000–€15,000 | €4,000–€8,000 | €2,500–€5,000 | €12,000–€28,000 |
| €20M – €50M | €15,000–€30,000 | €8,000–€15,000 | €4,000–€8,000 | €27,000–€53,000 |
| €50M – €100M | €30,000–€60,000 | €15,000–€30,000 | €8,000–€15,000 | €53,000–€105,000 |
| Over €100M | €50,000–€100,000 | €25,000–€50,000 | €12,000–€25,000 | €87,000–€175,000 |
Environmental scope adds €5,000–€25,000 depending on whether physical inspection is required.
These ranges assume a single-jurisdiction Spanish company with three years of orderly accounts and no ongoing tax inspections. Each of these assumptions that fails adds cost.
Scope Breakdown by Due Diligence Type
Financial Due Diligence
The core of any process. A financial DD reviews three to five years of accounts under the Spanish General Chart of Accounts (Plan General Contable, Real Decreto 1514/2007), normalises EBITDA by stripping out non-recurring items and owner-specific costs, analyses working capital trends, and determines adjusted net debt. On deals above €5M, the report typically includes a quality-of-earnings analysis that scrutinises accounting policy choices.
Tax Due Diligence
Reviews the company’s standing with the Agencia Tributaria (AEAT), covering: Corporate Income Tax (Impuesto sobre Sociedades) for the last four non-prescribed years under Article 66 of the Ley General Tributaria (LGT, Ley 58/2003); VAT returns (Modelo 303 and annual summary 390); payroll tax withholdings (Modelos 111, 115, 123); transfer pricing if the company belongs to a group; and any pending refund requests or open inspection procedures.
A recurring finding in Spanish mid-market deals: underdeclared dividends disguised as management fees, which the AEAT can reassess under the related-party rules of Article 18 of the Ley del Impuesto sobre Sociedades (LIS, Ley 27/2014).
Legal Due Diligence
Covers corporate structure, material contracts (leases, key customer and supplier agreements, IP licences), intellectual property and know-how, pending litigation, and the land registry situation for any real estate assets. Also includes review of the book of corporate minutes (libro de actas) and any existing shareholders’ agreement.
Labour Due Diligence
Examines headcount structure, the applicable collective bargaining agreement (convenio colectivo), individually negotiated conditions, any active or recently closed ERTEs, and Social Security contribution history. The acquirer’s joint and several liability for the target’s unpaid labour and Social Security debts — established under Article 44 of the Estatuto de los Trabajadores — makes this area non-negotiable in any share deal.
Environmental Due Diligence
Required when the acquisition involves real estate, industrial land or activities with a pollution risk profile. Cost depends heavily on whether a Phase I environmental site assessment (desk study) suffices or a Phase II physical inspection with soil sampling is needed. Spain’s Environmental Liability Law (Ley 26/2007) establishes objective liability for contaminated sites, which creates direct balance sheet exposure for acquirers.
Factors That Push Costs Higher
Multi-jurisdiction. A target with subsidiaries in Spain, Mexico and Colombia requires coordinated local teams. Cross-border deals can multiply the base cost by a factor of 2 to 3.
Regulated sectors. Financial services, healthcare, energy and telecommunications require specialist regulatory review of licences and authorisations whose revocation would materially affect the business. A pharmacy acquisition in Spain requires review of the regional health authority’s dispensing licence, which is non-transferable under most regional pharmacy laws.
Seller data quality. Disorganised bookkeeping, missing bank reconciliations or undocumented shareholder loan accounts can double the review time — and the fee. Sellers who prepare their data room properly recover that preparation cost in lower buyer DD fees at negotiation.
Open contingencies. Tax inspection notices currently under administrative appeal, Social Security disputes or pending employment tribunal claims require additional legal-tax analysis outside standard scope. Each open procedure adds both time and cost.
Compressed timelines. Competitive auction processes routinely require six weeks of work in three. That mobilisation premium typically adds 20–40% to base fees.
Who Pays for Due Diligence?
In standard Spanish acquisitions, due diligence is ordered and paid for by the buyer. If the deal does not close, those fees become an unrecovered sunk cost — which is why buyers are reluctant to commission full-scope DD before signing a solid letter of intent with an exclusivity clause.
Vendor due diligence inverts this logic. The seller commissions the report before launching the sale process with two aims: first, to identify and address contingencies before the buyer uses them to justify a price reduction; second, in auction processes with multiple bidders, to provide a common information platform that reduces each buyer’s individual DD burden and accelerates the timeline to signing.
VDD cost falls on the seller and runs at roughly 60–80% of a buyer DD. In private equity exits and corporate carve-outs, VDD has become standard practice. The rationale is straightforward: a cleaner, faster process at a higher price more than compensates for the advisory fee.
Timeline Benchmarks
Pace is determined less by deal size and more by data room quality and seller responsiveness.
| Complexity profile | Typical timeline |
|---|---|
| < €5M, clean accounts, single entity | 3–4 weeks |
| €5M–€20M, single jurisdiction | 5–7 weeks |
| €20M–€50M, moderate contingencies | 7–10 weeks |
| €50M+, multi-jurisdiction or regulated sector | 10–16 weeks |
Common bottlenecks: slow seller responses to information requests; AEAT tax clearance certificates (which can take 2–3 weeks during peak periods); and valuation of specific assets requiring specialist appraisers.
Reducing Costs Without Cutting Corners
Prepare the data room before marketing. Indexed documents, current bank statements, three years of signed accounts and up-to-date tax certificates can reduce review time by 30–40%.
Define scope precisely. A red-flag DD focused on the three highest-risk areas identified in the information memorandum is entirely appropriate for deals under €3M or where the buyer has strong sector knowledge. Cost can be half that of full-scope DD.
Use an integrated team. When four independent firms each produce siloed reports with no cross-referencing, fees multiply and findings conflict. A single multidisciplinary team with coordinated workstreams is structurally more efficient.
Negotiate the fee structure. For deals with meaningful closing uncertainty, a retainer-plus-success model is sometimes possible, though less common in DD than in investment banking mandates.
The Asymmetry That Makes DD Worth Every Euro
The relevant question is not how much due diligence costs. It is how much undiscovered contingencies cost after closing. In Spanish mid-market M&A experience, the ratio of contingencies identified to DD fees paid routinely exceeds 10:1. A €15,000 DD that identifies a €150,000 undeclared tax liability is not an expense — it is a return.
If you are evaluating an acquisition in Spain and need a scoped fee estimate, BMC’s Corporate Advisory team can assess the appropriate level of review for your specific transaction.
