Due diligence is far more than a formality prior to a merger or acquisition. It is the process that determines whether a transaction makes strategic, financial and legal sense. Conducting it properly can mean the difference between a successful investment and a costly mistake.
The critical phases of the process
A comprehensive due diligence process is structured in several clearly differentiated phases. The first is the planning phase, where the scope, objectives and responsible team are defined. It is essential to establish from the outset which areas will be analyzed: financial, tax, legal, employment, environmental and operational.
The second phase involves information gathering and analysis. Here, audited financial statements covering the last three to five years, key contracts, pending litigation, tax status and regulatory compliance are reviewed. The quality of this phase depends largely on the seller’s cooperation and the advisory team’s ability to identify hidden risks. A well-structured virtual data room, organized by subject area with version control, can significantly accelerate timelines and reduce the risk of omissions.
The third phase consists of preparing the due diligence report, where each area documents its findings, quantifies identified risks and formulates specific recommendations for the negotiation process. This report forms the basis for price adjustments, warranty clauses and conditions precedent in the sale and purchase agreement.
Critical areas of analysis
Financial and tax due diligence
The financial review must go beyond reading annual accounts. It is essential to analyze earnings quality (adjusting EBITDA for extraordinary or management items), working capital evolution, net financial debt and future commitments such as operating leases, capital expenditure obligations or off-balance sheet contingencies.
In the tax area, the analysis must cover the last four years (the general tax limitation period in Spain is four years under Article 66 of the General Tax Law), including Corporate Income Tax, VAT, income tax withholdings and the status of deferrals or disputes with the AEAT. Tax contingencies identified are usually addressed through specific warranty clauses or price retentions pending their resolution.
Legal and contractual due diligence
The legal review should encompass the complete corporate structure, existing shareholder agreements, contracts with strategic clients and suppliers, intellectual and industrial property, and pending or latent litigation. Change of control clauses in financing agreements or with key clients can materially affect the value of the transaction if not identified in time.
Intellectual property deserves particular attention in technology companies or those with significant brands. Verifying that the company has full ownership of key intangible assets — internally developed software, registered trademarks, patents — and that there are no third-party licenses with restrictive conditions is a critical part of the analysis.
Common mistakes and how to avoid them
One of the most common mistakes is underestimating the importance of employment analysis. Contingencies arising from collective bargaining agreements, pension plans or pending labor disputes can represent significant liabilities that completely alter the valuation of the transaction. The subrogation of employment contracts in an asset acquisition or the assumption of Social Security debts are aspects that must be quantified with precision.
Another frequent error is not paying sufficient attention to contracts with strategic clients and suppliers. Change of control clauses, renewal conditions and warranties granted can have a material impact on the post-acquisition viability of the business. In regulated sectors — energy, telecommunications, financial services — the transferability of administrative licenses is a prerequisite that must be verified before signing any binding agreement.
A third common mistake is approaching due diligence with an insufficient team or excessively tight timelines. A rushed process increases the risk of missing contingencies that could have been negotiated into the price or warranty clauses. Transactions that have omitted critical areas of review have resulted in post-closing litigation whose cost far exceeds what a more rigorous process would have entailed.
Structuring the advisory team
A complex due diligence requires a coordinated multidisciplinary team. The buyer typically designates a financial advisor to coordinate the process and a specific legal team for the legal review. In cross-border transactions, local advisors are engaged in each relevant jurisdiction.
The role of the single coordinator — a senior member of the advisory team with a global view of the transaction — is essential to prevent different workstreams from operating in silos and to ensure that findings are coherently integrated into the final report and negotiations.
Best practices
From our experience in over two hundred transactions, we recommend establishing a well-organized virtual data room from day one, appointing a single coordinator to centralize communications and using standardized checklists adapted to the specific sector of the target company. Setting realistic timelines for each phase — typically four to eight weeks for a mid-sized due diligence — and maintaining fluid communication with the seller to resolve questions without delay are factors that make a material difference to the quality of the process.
Due diligence should not be viewed as a cost but as an investment in security. A rigorous process allows you to negotiate better terms, structure adequate warranties and, sometimes, make the most valuable decision of all: not proceeding with the transaction. Identifying a hidden liability or an unquantified critical dependency early enough can save millions and avoid years of post-closing litigation.
