Due diligence in Mexico: a guide for sellers and buyers

Due diligence is the stage of the M&A process where the buyer verifies everything the seller has stated — and uncovers what was not disclosed. It is when deals fall apart, prices get renegotiated, and conditions get tougher.

What areas due diligence covers, how long it takes, what documents are requested, and how to prepare so you reach closing with the LOI price intact. More in LOI and due diligence.

Due diligence is not a formality. It is an adversarial audit. The buyer looks for reasons to cut the price or walk. The seller’s preparation determines the outcome.

What does financial due diligence cover?

The financial review is the most critical. The buyer reconstructs normalized EBITDA on their own — if they find gaps versus what was presented in the CIM, the price moves. The four focus areas: EBITDA quality (recurring vs. extraordinary revenue, documented vs. discretionary adjustments), working capital (is the historical level sustainable?), hidden debt (unrecorded liabilities, guarantees, tax contingencies), and customer concentration (what share comes from the top 3 customers?).

A well-documented EBITDA bridge — every adjustment explained, every number backed — shortens financial due diligence and reduces the buyer’s room to challenge the number. More in normalized EBITDA.

What does legal due diligence cover?

The buyer reviews the full corporate structure: minutes, registers, notarial powers. Customer contracts — term, change-of-control clauses, automatic renewals. Key supplier contracts — exclusivities, dependencies. Active or historical litigation. Intellectual property — trademarks, patents, software. In Mexico asset purchases are more common than share purchases precisely because the buyer does not want to inherit hidden liabilities. More in representations and warranties.

What do operational and labor due diligence cover?

Operational: mapping of critical processes, IT systems, single-supplier dependencies, owner transition plan. Labor: full payroll, individual and collective contracts, outsourcing (2021 reform compliance), IMSS and SAT contingencies, above-law benefits. Owner dependence is the most common finding in SME — and the one that most pushes toward a large contingent tranche or an earnout. If the founder is the main relationship with key customers, the buyer will model it as risk.

How long does due diligence take?

In Mexican SME transactions: 6 to 10 weeks from opening the data room to closing out findings. Factors that lengthen the process: incomplete or disorganized data room, slow responses to information requests, findings that need further analysis, negotiation of price or condition adjustments. A data room prepared before the process — not assembled under pressure — is the variable the seller can control most.

How to prepare as a seller?

Four concrete actions before opening the data room:

• Normalize EBITDA with documentation. Every adjustment must have backup. The buyer will reconstruct the number — if the bridge is documented, the seller controls the starting point. Use the normalized EBITDA calculator.
• Organize the data room by area. Financial, legal, operational, labor, tax — each section complete before granting access. A data room with gaps invites questions and lengthens the process.
• Disclose known risks proactively. Findings the buyer discovers on their own carry more weight than those the seller disclosed. A minor litigation disclosed in the CIM is a data point; discovered in diligence it is a red flag.
• Address owner dependence before starting. Document processes, transfer key relationships, have a clear transition plan. Every unresolved dependence becomes an argument for a longer earnout or a lower price.

What are the most common seller mistakes in due diligence?

• Reactive data room. Building the data room in response to buyer requests — document by document — lengthens the process by weeks and signals disorganization.
• EBITDA without documented bridge. If the buyer cannot reconcile the EBITDA presented with the financial statements, they reconstruct the number in their favor.
• Contracts not reviewed. Unidentified change-of-control clauses can block closing or require consents that delay by weeks.
• Tax contingencies not disclosed. Differences between tax and financial accounting, unregularized outsourcing, questionable tax credits — if the buyer discovers them, they are ammunition for price adjustment.
• No transition plan. A founder who cannot articulate how the operation is transferred in 90 days turns dependence into measurable risk.

What do buyers and sellers ask about due diligence?

What is a data room and what should it contain?

A data room is the centralized repository of documents the seller shares with the buyer during due diligence. It should contain: audited or compiled financial statements for the last 3–5 years, tax returns, key contracts with customers and suppliers, corporate structure and minutes, payroll and employment contracts, intellectual property and asset records, and any active litigation or contingencies. More in data room.

Can the buyer renegotiate the price after the LOI?

Yes. The LOI sets indicative terms but is not binding on price. If due diligence produces material findings — EBITDA lower than presented, hidden liabilities, customer concentration not disclosed — the buyer has grounds to adjust price or conditions. The seller’s protection is preparation: an accurate CIM, a complete data room, and risks disclosed proactively reduce room for renegotiation. More in LOI.

What is the difference between financial and accounting due diligence?

Financial due diligence analyzes the quality and sustainability of EBITDA, capital structure, and working capital. Accounting due diligence verifies that financial statements were prepared correctly and that there are no material errors. In Mexican SME transactions both are run together by the buyer’s accountant or firm.

What happens if the buyer finds a serious issue?

It depends on materiality. A minor finding (expired contract, unpaid benefit) is resolved with a specific representation and warranty or a small adjustment. A serious finding (material undisclosed litigation, significantly inflated EBITDA, quantifiable tax contingency) results in price adjustment, additional closing condition, or deal withdrawal. More in representations and warranties.