Selling a company is, for most business owners, the single most important financial transaction of their life. Yet the majority of sellers arrive at due diligence in the same condition: documentation scattered across filing cabinets and email threads, the corporate minutes book untouched for years, and accounts mixed with personal expenses that nobody ever questioned. The outcome is predictable and quantifiable. The buyer identifies uncertainty, converts it into risk, and applies a discount. In Spanish mid-market transactions, that discount for lack of preparation typically falls between 10% and 20% of the price agreed in the initial letter of intent.
This guide is written from the seller’s advisor perspective. Not from the buyer’s side — which is where the vast majority of due diligence content is written — but from the side of the team that has to get the company ready to withstand scrutiny. Proper preparation, done with enough lead time, does not just eliminate discounts. It can become a positive price argument.
Why preparation determines the price
M&A pricing theory is, at its core, a theory about information and risk. When a buyer perceives uncertainty — because the financial statements do not reconcile with the tax returns, because important contracts are not signed, because the Registro Mercantil shows outdated data — the uncertainty does not disappear from the valuation. It becomes a discount that compensates for the perceived risk. The mechanism is never explicit in the term sheet, but the effect is always the same.
The so-called uncertainty discount is the mechanism by which buyers translate unresolvable uncertainty into price reduction. In the Spanish market for transactions between EUR 2 million and EUR 50 million, financial advisors estimate this discount represents between 8% and 22% of the base price when the seller arrives unprepared. For a business that should be worth five million euros, that is between EUR 400,000 and EUR 1.1 million left on the table.
Preparation does not eliminate all risks — no preparation process can do that — but it converts risks from “unknown” into “known and already resolved.” That is precisely what buyers value: not the absence of problems in the past, but the certainty that problems that existed have been identified and corrected before closing.
The six workstreams of seller due diligence preparation
Professional preparation covers six areas of work, which are exactly the same areas the buyer’s team will review. The advantage for the seller who works through them first is the ability to anticipate findings, quantify their impact, and either correct them or prepare the explanatory narrative before the buyer discovers them independently.
1. Financial workstream
The financial preparation work has two dimensions: cleaning up historical statements and normalising presentable EBITDA.
Cleaning up historical statements means ensuring that the annual accounts filed at the Registro Mercantil are consistent with the Impuesto sobre Sociedades (corporate income tax) returns and with the internal management accounts. In Spanish mid-market companies it is common to find significant differences between all three documents, often explained by year-end adjustments made by the tax advisor without simultaneously updating the other documents. The buyer will cross-reference all three systematically, and any unexplained difference generates questions that slow the process.
EBITDA normalisation is the most delicate work and the one with the greatest impact on price. In family-owned businesses and SMEs, the EBITDA shown in the profit and loss account typically includes expenses that do not belong to the business: the owner’s car, rent paid to the owner’s property company at above-market rates, salaries for family members on the payroll who provide no real services, or travel expenses that mix professional and personal costs. Normalising EBITDA means calculating what result the business would have generated if run by a professional management team without those adjustments. The difference between reported and normalised EBITDA can be substantial, and in transactions with multiples of 5x to 8x, every EUR 100,000 of positive normalisation is worth EUR 500,000 to EUR 800,000 in additional price.
The most frequent normalisation items in Spanish companies are: owner-manager salary above or below market rates, related-party transactions at non-market prices (purchases from a spouse’s company, rent paid to the majority shareholder’s separate property entity), non-recurring costs (resolved litigation, one-off restructuring charges), and capital investments that were expensed rather than capitalised.
2. Tax workstream
The tax position is the area that generates the most anxiety among Spanish buyers, and justifiably: the general tax limitation period is four years under Article 66 of the General Tax Law (Ley General Tributaria), meaning the buyer acquires along with the company the risk of tax inspections covering the four financial years preceding closing.
Tax preparation begins with an honest risk map: are there related-party transactions without transfer pricing documentation? Have there been expense deductions whose connection to the business activity is questionable? Are there pending VAT refunds subject to verification? Were any restructuring transactions carried out in the last four years without the economic documentation justifying their tax neutrality?
The objective of this mapping is not to hide problems from the buyer — real problems that cannot be regularised must be incorporated into the negotiation as known contingencies — but to distinguish between real risks and apparent risks. Many situations that appear to be tax contingencies at first glance are resolved simply by producing the right documentation: a valuation report for a related-party transaction, the lease agreement that justifies the rent deducted, the supplier invoice that supports the disputed expense.
By the time the buyer accesses the data room, the seller should have in digital format: the last four Modelo 200 filings (corporate income tax), the last four Modelo 390 filings (annual VAT summary), the last four Modelo 190 filings (annual withholding tax summary), and most importantly, a current tax standing certificate from the AEAT and a social security standing certificate from the Tesoreria General de la Seguridad Social (TGSS). These certificates are valid for six months, but for an active sale process we recommend obtaining them no more than thirty days before the process begins.
If tax inspection or verification proceedings are in progress, the most advisable approach is to disclose them to the buyer from the outset and quantify them as precisely as possible. Attempting to conceal them is not only ethically questionable but legally counterproductive: an inaccurate representation in the sale and purchase agreement about the absence of pending tax disputes can create seller liability for fraud or bad faith that in many cases exceeds the underlying tax contingency.
3. Legal and corporate workstream
Legal housekeeping is the area where Spanish mid-market companies show the most systematic deficiencies. The three most frequent are: an out-of-date corporate minutes book, a Registro Mercantil with incorrect or expired data, and missing or unsigned contracts with key clients and suppliers.
Corporate minutes book (Libro de actas). The Ley de Sociedades de Capital and Articles 26 et seq. of the Codigo de Comercio require that all meetings of the shareholders’ general assembly and the board of directors be recorded in consecutively numbered, signed minutes. In practice, many mid-market companies have gone years without holding formal meetings, or have held them without producing written minutes. A buyer knows that a minutes book with gaps conceals decisions taken outside corporate governance channels, which is a governance risk they cannot easily quantify. The fix is relatively straightforward: draft and sign the pending minutes before opening the data room. A legal advisor can reconstruct the historical record of resolutions adopted — dividends paid, director appointments and removals, statutory amendments — from available documentation.
Registro Mercantil. Annual accounts are frequently not filed for all years within the reviewable period, directors listed in the register do not match those actually managing the company, or the bylaws have not been updated following capital increases or changes in the company’s corporate object. The Registro Mercantil is the first place the buyer’s lawyers will check. Discrepancies between the register and the actual state of the company are not a minor issue: they raise doubts about the real ownership of the participaciones and the validity of resolutions adopted.
Client and supplier contracts. In many mid-market businesses, relationships with key clients rest on verbal agreements, general terms of sale that were never formally accepted, or email chains with no contractual weight. Before opening the data room, the seller should identify the ten largest clients and five largest suppliers and verify that a signed written contract exists for each, with clear conditions on price, term and termination. If contracts do not exist, the sale process is the best possible incentive to create them: a buyer who discovers that 40% of the company’s revenue is based on verbal agreements has negotiating leverage they should not have.
Intellectual and industrial property. Trademarks, trade names, websites and any internally developed software must be registered or documented in the company’s name, not in the founder’s personal name. It is common to find that the company’s domain is registered to the founder personally, that the brand was never registered at the OEPM (Spanish Patent and Trademark Office), or that software the company sells was developed by a freelancer without a rights-assignment agreement. Each of these is a problem the buyer will identify, which in the best case becomes a condition precedent that delays closing.
4. Employment workstream
Employment due diligence is the area where contingencies most frequently arise that the seller had not anticipated. The four most common in Spanish companies are: employees registered under job categories below the functions they actually perform (creating risk of back-pay claims), workers on temporary contracts that have exceeded the legal limits and should have been converted to indefinite contracts, senior executives without a proper senior management contract (contrato de alta direccion) whose termination entitlements are uncertain, and self-employed contractors working under conditions that the Labour Inspectorate would classify as disguised employment relationships (falsos autonomos).
Before launching a sale process, the seller’s employment advisor should conduct an internal audit of the entire workforce. The output should be a complete employee census including: name, job category, applicable collective bargaining agreement (convenio colectivo), actual start date, contract type and salary. This census is the starting document for the buyer’s employment due diligence, and the more complete and ordered it is, the lower the perceived risk.
A frequently overlooked aspect is key person retention. In mid-market companies it is common for one or two executives to concentrate 60% to 70% of the significant client relationships, the technical knowledge of the production process, or day-to-day banking relationships. A buyer who detects this dependency without a solution in place will demand a retention structure — earn-out clauses tied to key person continuity, or contractual lock-in commitments from key executives as a closing condition — which can be very restrictive for both the seller and the executives themselves. Anticipating this problem, and designing retention contracts or incentive structures for key executives before the process begins, converts a vulnerability into an asset.
Finally, if the company has been involved in a Collective Redundancy Procedure (ERE or ERTE) in the last four years, the buyer will review the documentation of that process in detail. The formal regularity of the procedure, the payment of all committed severance and allowances, and the absence of pending employee legal challenges must all be verified before the buyer’s due diligence team arrives.
5. Commercial and operational workstream
Commercial due diligence analyses the sustainability of the business model: customer concentration, revenue recurrence, dependency on contracts that are approaching expiry, and competitive positioning. From the seller’s perspective, the work in this area consists of building a coherent and documented narrative about why the business will remain profitable after the change of ownership.
The three problems buyers look for most actively are: excessive customer concentration (when a single client represents more than 30% of revenue, the buyer perceives a risk of losing that client after closing and applies a discount); contracts with important clients that expire within twelve months without guaranteed renewal; and dependency on the seller’s personal profile as the visible face of the business with clients.
For the concentration issue, preparation means formalising multi-year contracts with the most relevant clients before launching the process. For near-term contract expirations, it means negotiating extensions or automatic renewal clauses before the buyer discovers the expiry date. For personal dependency on the founder — which has no quick fix — it is a structural risk that requires advance management through genuine delegation of client relationships to members of the management team.
6. Environmental workstream
For most service companies, the environmental workstream has limited impact on due diligence. However, for industrial, transport, food or companies with significant physical premises, it can be the area where the most costly and difficult-to-resolve contingencies appear.
The questions the buyer will ask are: has the company or its premises operated activities classified as requiring an environmental permit (licencia ambiental)? Is there an environmental inspection in progress or concluded with a remediation requirement? Have there been discharges or waste management irregularities in the past? Does the property where the company operates have potentially contaminated soil?
For companies with environmental exposure, the most advisable step is to commission a Phase I Environmental Site Assessment before launching the sale process. The cost is relatively modest (EUR 3,000 to EUR 8,000 for mid-size premises), but it allows the seller to identify and document the actual state of the premises before the buyer does, eliminating uncertainty as a price-discount factor.
Building the data room: structure and required documents
The data room — physical or virtual — is the company’s showcase during the due diligence process. Its organisation and completeness shape the buyer’s perception from the first moment. A well-structured data room communicates control, order and preparation. A disorganised one, with poorly scanned documents, incoherent folder structures and missing critical files, communicates the opposite.
The standard structure for a Spanish mid-market company is as follows:
1. Corporate and statutory
- Deed of incorporation and all subsequent amendments
- Current bylaws (consolidated version)
- Corporate minutes book (digitised, complete and signed)
- Updated register of shareholders (libro registro de socios)
- Beneficial ownership certificate from the Registro Mercantil
- Relevant shareholder notifications (dividends, pre-emption rights exercises)
2. Financial
- Annual accounts for the last four financial years (management report + balance sheet + profit and loss + notes)
- Audit reports (if applicable) or administrator certification if statutory audit not required
- Monthly management accounts for the last twelve months
- Financial projections for the next two financial years with supporting assumptions
- Detail of financial debt: credit facilities, loans, leasing, renting (with amortisation schedules)
- Working capital detail: receivables, payables, inventory (with ageing analysis)
3. Tax
- Modelo 200 filings for the last four years
- Modelo 390 filings for the last four years
- Modelo 190 filings for the last four years
- Current tax standing certificate from the AEAT
- Current social security standing certificate from the TGSS
- Any tax inspection reports or ongoing verification proceedings
- Transfer pricing documentation (if related-party transactions exist)
4. Legal and contractual
- Contracts with the ten largest clients
- Contracts with the five largest suppliers
- Property or premises lease agreements
- Financing agreements
- Relevant confidentiality agreements (NDAs)
- Summary of pending litigation and supporting documentation for material cases
- Intellectual and industrial property registrations (OEPM, EUIPO, domain names)
5. Employment and HR
- Complete employee census (names, categories, seniority dates, contract types)
- Applicable collective bargaining agreement
- Contracts for key executives
- ERE/ERTE documentation if applicable
- Works council minutes (if a works council exists)
- Last twelve months of payslips and Social Security contribution summaries (TC2)
6. Operational and commercial
- Business model description
- Client portfolio with revenue by client for the last three years
- Updated sales pipeline
- Distribution or agency agreements (if applicable)
- Relevant certifications and permits (ISO standards, sector-specific authorisations)
7. Assets and environmental
- Title deeds for owned real estate or updated Registro de la Propiedad notes
- Fixed asset inventory for material items
- Current insurance policies
- Business licence (licencia de apertura y actividad)
- Environmental assessment (if conducted)
Financial clean-up: the most profitable preparation work
EBITDA normalisation and accounting clean-up are, by a significant margin, the preparation work with the highest return for the seller. Every euro of normalised EBITDA that is credibly documented multiplies by the transaction multiple. With multiples of 5x to 7x common for Spanish mid-market service companies, normalisation work that substantiates EUR 100,000 of additional clean EBITDA is worth EUR 500,000 to EUR 700,000 in price.
The items most frequently subject to favourable normalisation for sellers are:
Owner-manager salary above market rates. If the owner has assigned themselves a salary of EUR 200,000 when the market rate for a CEO of a company of that size would be EUR 120,000, the EUR 80,000 difference can be normalised as additional EBITDA, on the argument that a professional buyer would not maintain that salary level.
Personal expenses run through the company. Private life insurance, premium vehicles, entertainment expenses that are effectively personal, club memberships. All these items, if removed from operating costs, increase normalised EBITDA.
Related-party rent at non-market rates. If the company operates from premises owned by the majority shareholder and pays rent that does not correspond to market value — whether above or below — the normalisation adjusts rent to market rate, affecting EBITDA accordingly.
Non-recurring costs. Resolved litigation costs, one-off restructuring expenses, losses from the closure of a business line that no longer exists. These costs are not representative of the going-concern cost base and are removed from normalised EBITDA.
Each normalisation adjustment must be documented and supported. The buyer will challenge every positive adjustment, so the golden rule is: only include in the normalisation what can be demonstrated with a contract, an invoice, a valuation report or a verifiable market data point.
Tax position: resolve rather than reveal
The general principle in tax preparation for a sale process is straightforward: it is always better to resolve than to reveal. Tax contingencies disclosed to the buyer as “pending risk” are discounted from the price at the value of the contingency plus an uncertainty premium. The same contingencies that have been regularised before the process become resolved history, which generates no discount.
The elements of the tax position that deserve priority review are:
Related-party transactions without transfer pricing documentation. Article 18 of the Ley del Impuesto sobre Sociedades requires documentation of transactions between entities in the same group or between the company and its shareholders. If such transactions have been conducted without the required documentation, the buyer will identify this immediately, and the contingency can be substantial.
Questionable VAT positions. Transactions where the deductibility of input VAT is arguable, supplier invoices that lack genuine commercial substance, or VAT deductions on investment assets used partly for private purposes.
Corporate income tax: uncompensated tax loss carry-forwards (BINs). If the company has tax losses pending offset against future profits, this is an asset the buyer may value, but it must be properly documented. An inspection of the BINs could create problems if the documentation for the years in which they were generated has not been retained.
The four-year tax limitation period is the temporal framework that delimits the buyer’s exposure. For a transaction closing in 2026, the financial years 2022, 2023, 2024 and 2025 are within the non-prescribed period. If the seller can demonstrate the absence of material contingencies in those four years, the principal source of tax price discount has been eliminated.
Legal housekeeping: what seems minor but is not
There is a category of legal tasks that business owners tend to postpone indefinitely because they have no immediate impact on operations. A sale process converts all of them into urgent simultaneously. Addressing them in advance prevents them from becoming closing obstacles.
The most frequent are: trademarks the company uses as its own but never formally registered at the OEPM; the company website domain registered in the founder’s personal name rather than the company’s; software developed without a rights-assignment agreement with the developer; properties with registral encumbrances (mortgages economically cancelled but not formally released at notary, requiring registral cancellation before closing); and premises lease agreements without a renewal clause or with a landlord pre-emption right that could be triggered by the business sale.
Each of these, discovered by the buyer in due diligence, becomes a condition precedent to closing: the sale and purchase agreement is not signed — or does not take effect — until the issue is resolved. Conditions precedent delay closing, during which the market context can shift, buyer motivation can cool or new issues can emerge. Resolving them before the data room opens simplifies the process considerably.
The timeline: start 12 months before going to market
The optimal preparation sequence, assuming the seller wants to begin marketing (sending the Information Memorandum to prospective buyers) at month 12, is as follows:
Months 1-3: diagnosis and planning. Internal audit of all six workstreams: financial, tax, legal, employment, commercial and environmental. The objective is to identify all known problems before the buyer does. This diagnosis must be honest and thorough: there is no incentive at this stage to ignore problems that will inevitably surface during due diligence.
Months 3-6: contingency resolution. Regularising the issues identified: updating the corporate minutes book, correcting accounting inconsistencies, signing pending contracts, resolving employment irregularities, updating the Registro Mercantil, filing intellectual property registrations.
Months 6-9: financial normalisation and data room construction. Preparing normalised financial statements with documented EBITDA adjustments, organising the virtual data room, drafting the Information Memorandum and the financial model to be shared with buyers.
Months 9-12: final review and market launch. Obtaining updated tax and social security standing certificates, having the seller’s financial advisor review the data room, identifying prospective buyers and preparing the first round of outreach.
Red flags buyers systematically look for
Experienced buyer due diligence teams look for a consistent set of red flags, because in past transactions they have learned these are predictors of deeper problems.
The first is inconsistency between financial statements and operational data. If the company claims to invoice EUR 8 million to one hundred clients, but the client list in the data room adds up to only EUR 6 million, the gap requires immediate explanation. If gross margins in 2025 are significantly worse than in 2024 without a clear explanation, the buyer will conclude the business is deteriorating and will revise projections downward.
The second is excessive dependence on a single person, client or supplier. A CEO who is the only one with relationships with the main clients, a client representing 45% of revenue, a supplier accounting for 70% of procurement. Each of these factors increases the perceived post-closing risk.
The third is a spike in short-term debt over the last twelve months. When the balance sheet shows a significant increase in credit facilities or bank overdrafts in the most recent period, the buyer interprets this as cash flow tensions that are inconsistent with the reported EBITDA.
The fourth, and often the hardest for the seller to manage, is changes in key executive behaviour during the process. When key employees sense a sale is under way without having been informed, the typical reaction is to begin exploring alternatives. Managing internal communication during a sale process — deciding when and how to inform key people — is one of the most delicate decisions the seller must make with their advisor.
The vendor due diligence report: what it is and when to commission it
A vendor due diligence (VDD) is a due diligence report commissioned by the seller, prepared by independent advisors, and then shared with interested buyers. It is the equivalent of a technical inspection of a property paid for by the seller before listing it.
Its advantages for the seller are threefold. First, it allows the seller to control the process: the seller knows what is there before the buyer does, and can decide how to present the findings. Second, it reduces the total process timeline: if the VDD is of sufficient quality, buyers can rely on it rather than running their own full independent process, reducing due diligence time from eight to four or five weeks. Third, in processes with multiple prospective buyers, it allows all parties to access the same base information without the seller having to manage several simultaneous due diligence teams with access to their organisation.
Its limitations are equally real: it has a cost (EUR 15,000 to EUR 80,000 depending on company size and complexity), and sophisticated buyers will always conduct their own verification on the most material points, meaning it does not eliminate the buyer’s due diligence process entirely.
A VDD makes sense when the company has a certain level of complexity (multiple business units, operations in several jurisdictions, group structure), when multiple simultaneous buyers are anticipated, or when the seller has a particular interest in accelerating the process or controlling the narrative of findings from the outset.
The decision of whether to commission a VDD is one of the first to be made in sale process planning, precisely because it affects the timeline and the structure of the marketing process.
Preparing a company for sale is an investment, not an expense. Owners who spend twelve months putting their house in order — financial, tax, legal and employment — do not just arrive at due diligence with complete documentation. They arrive with a coherent narrative, with contingencies already resolved, and with the confidence that comes from knowing the real situation of their company in full. That difference, in price, can be decisive.
