Success and Failure in Mergers and Acquisitions

Success and Failure in Mergers and Acquisitions: The truth about M&A

Inorganic growth through mergers and acquisitions (M&A) is one of the most powerful tools for competitive transformation, internationalisation and the consolidation of operating capabilities. Yet the evidence gathered by academia and the leading strategy consultancies points to a demanding reality: most corporate transactions destroy value rather than create it. Recurring research places the M&A failure rate between 70% and 90%. This is not a cyclical effect of the financial markets, but the result of repeated methodological shortcomings across planning, valuation, due diligence and integration.

Failure shows up in measurable parameters. A deal is deemed to have failed when the acquirer underperforms its sector peers over a one-to-three-year horizon, when it captures less than 70% of the originally projected synergies, or when the acquired asset is divested or wound down within five years of signing — an explicit admission of strategic failure.

The propensity to fail depends heavily on the buyer’s transactional experience. First-time acquirers show a success rate of just 25%, owing to the absence of structured corporate-development teams. Serial acquirers — ten or more deals executed under repeatable methodologies — reverse the trend, reaching a 50% success rate.

Why deals fail: from financial optimism to deficient due diligence

The root of failure is rarely macroeconomic; it lies in cognitive biases and technical omissions made before signing. One of the most common errors is jumping prematurely to an acquisition decision without stress-testing the alternatives of organic growth or commercial alliances. Driven by the urgency to grow, this bias leads to disproportionate acquisition premiums that undermine the viability of the combined group.

Around 31% of failures are attributable directly to deficient due diligence. Pressure to close quickly produces superficial reviews that treat the process as administrative box-ticking rather than as a risk audit and a validation of the value hypothesis. That lack of depth prevents the detection of hidden liabilities, tax contingencies, litigation or working capital inefficiencies that surface destructively after closing. In Spain, moreover, the tax authority (AEAT) can formally request the due diligence report during an inspection of a share transfer, which raises the risk if the process has not been rigorously documented.

The weakness of traditional due diligence lies in its financial, backward-looking focus, which overlooks the audit of intangibles and operating variables that are decisive for long-term sustainability: customer loyalty, the commitment of middle management or technological compatibility. Without that scrutiny, the acquisition model rests on revenue and cost assumptions with no real operational basis. A vendor due diligence prepared by the seller before going to market reduces precisely that asymmetry, and a financial due diligence checklist helps ensure no area is left uncovered.

The most frequent due diligence omissions

The Spanish mid-market: succession, ICO strains and the silent death of deals

The Spanish mid-market — companies with revenues between €1m and €50m — behaves very differently from large multinational transactions. In an economy where 99% of the business fabric is made up of SMEs that generate more than 75% of employment and 65% of GDP, sectoral consolidation is critical to reaching the scale that enables investment in digitalisation and innovation. Yet the market is fragmented and dominated by family-owned businesses.

Founder dependence is the segment’s most pronounced trait. When ownership, management, the customer relationships and the operating know-how all reside in a single person, risk rises sharply for the buyer: the asset can begin to depreciate the moment the founder signs the transfer of control, unless detailed transition plans or deferred-payment mechanisms such as an earn-out are structured. Family-owned SMEs’ reluctance to cede control and unresolved generational handovers delay or derail many negotiations. Anticipating these points is part of preparing the company for sale.

The segment is also shaped by financial restructuring. The progressive maturity of the state-backed ICO credit lines granted during the pandemic has introduced liquidity strains in SMEs with tight margins and leveraged balance sheets, acting as a driver of defensive M&A: sound companies seize the moment to acquire capital-stressed competitors. When financial stress is the trigger, the deal intersects with debt restructuring and refinancing processes.

Unlike large deals, mid-market transactions suffer what is known as the silent death of deals: a high share of agreements collapse weeks before signing because of friction accumulated during due diligence, the seller’s emotional disengagement, or the inability to close the financing. The weakness is sharper in deals with complex payment structures — bank debt, equity, vendor reinvestment and deferred payments all at once — which show far higher break rates than all-cash deals.

Mid-market diagnosis and mitigation

On the choice of structure, it is essential to be clear about the difference between an asset deal and a share deal, as it shapes both the risk assumed and the deal’s tax treatment.

The synergy mirage and the impact of cultural friction

The control premium is justified to shareholders by the promise of synergies. But the empirical reality is adverse: organisations systematically overestimate the benefits of consolidation. According to firms such as Bain and McKinsey, acquirers capture on average around 70% of projected cost synergies, but revenue synergies collapse to a 40-50% range.

Revenue synergies — cross-selling across consolidated customer portfolios — are hard to realise because of market resistance and misaligned sales teams. Modelling them requires discipline. The payback period on the premium links total outlay to real synergies:

Payback = (Acquisition premium + Integration costs) / Annual net synergies

Integration and restructuring costs must be fully provisioned, avoiding the error of assuming that unifying structures is free. And the revenue model must build in realistic corrections: customer churn of 5-15% in the first year and cross-sell take-up limited to 10-25% of the addressable base. Synergy quantification is, in fact, a discipline in its own right within deal analysis.

Synergies by type: magnitude, timing and realisation

Beyond operational or technological incompatibilities, cultural friction is the most destructive intangible factor. Culture defines leadership, decision-making, commercial speed and team autonomy. When two organisations with antagonistic identities merge without an explicit change-management plan, productivity falls and critical human capital is lost. The risk peaks in technology or professional-services acquisitions, where value resides in people: imposing hierarchical rules on an agile SME can trigger voluntary turnover of 20-40% in the first eighteen months, destroying the very advantage that justified the purchase.

The role of the Maraz adviser in engineering and defending value

In the mid-market, the asymmetry in experience, negotiating power and analytical resources between a family-business owner and an institutional buyer can lead to unfavourable deals and the silent destruction of value. Engaging a firm specialised in M&A advisory such as Maraz Corporate Finance professionalises the process, mitigates execution risk and secures the best available market terms, freeing the management team to focus on the day-to-day profitability of the business. The contribution is structured in four phases:

Phase I — Strategic preparation of the company

Analysis of the balance sheet and income statement, with EBITDA normalisation to strip out personal expenses and non-recurring items. Determination of a valuation range combining discounted cash flow (DCF), comparable multiples and precedent transactions. Preparation of the blind profile (teaser) and the Information Memorandum (CIM).

Phase II — Targeting and internationalisation of the process

Identification and qualification of candidates, distinguishing strategic buyers (able to capture synergies and pay more) from financial investors. The process runs under strict confidentiality — starting with a non-disclosure agreement (NDA) — and in a controlled competitive setting, to push entry multiples upward. Among the possible buyers are specific profiles such as the search fund.

Phase III — Offer engineering and negotiation of terms

Leadership in negotiation and the arbitrage of proposals, beyond the headline figure: time value of money, guarantees, retention periods and the suitability of variable-payment structures. Everything is formalised in a well-structured Letter of Intent (LOI) that sets the milestones of the process and protects the owner from unfavourable clauses.

Phase IV — Due diligence, contract and closing

The stretch between the LOI and signing is the one with the most friction. The adviser runs the Data Room, coordinates the buyer’s auditors and neutralises attempts to renegotiate downward on immaterial contingencies, working with legal counsel to draft the Share Purchase Agreement (SPA) with limited indemnity clauses.

The 100-Day Plan: the tactical core of integration

A deal is not won with the public deed; that milestone is merely the start of the critical phase: integration. More than 60% of value destruction originates in execution failures during post-merger integration (PMI), driven by a lack of planning before closing. To prevent it, set up a centralised, cross-functional Integration Management Office (IMO), led by an Integration Director with executive authority. The instrument that guides the process is the 100-Day Plan, focused on protecting the stability of the acquired business and sequencing transformations prudently.

Days 1-30 — Stabilisation and risk control

Top priority: reduce employee uncertainty and guarantee continuity. Mass communication clarifying reporting lines and confirming payroll and benefits; joint visits to strategic customers to reaffirm service commitments; and preservation of the ordinary accounting methodology and billing cycles, without touching cash management so as not to degrade cash flow.

Days 31-60 — Process transition

Audit of active projects against their original margins and of the backlog against the valuation model’s assumptions. Inventory of ERP, CRM and databases to plan migration with parallel testing phases. Retention plans for key professionals and first centralised purchasing to start capturing cost synergies.

Days 61-100 — Optimisation and first strategic execution

Definitive design of the operating model: which decisions remain local and which are centralised, preserving the commercial agility that justified the purchase. A dashboard of PMI KPIs (retention of key customers, business volume, capacity utilisation and degree of synergy realisation) and validation of the assumptions that justified the premium, with a six- and twelve-month development plan.

Continuity of the finance function during this phase is decisive; when the acquired company lacks it, a fractional CFO can pilot the financial integration and treasury control of the period.

Conclusion - Success and Failure in Mergers and Acquisitions

The high M&A failure rate is not a reason to give up on inorganic growth, but a warning against analytical improvisation, financial optimism and the absence of post-signing planning. In the Spanish mid-market and family business, M&A is an indispensable lever to gain scale, resolve generational transitions and professionalise structures. The difference between destroying and creating value lies in the rigour applied across the whole cycle: deep due diligence, prudent synergy modelling and, above all, a 100-Day Plan that manages the cultural and technological transition.

If you are considering an M&A transaction — as a buyer or a seller — and want to professionalise the process to protect value, Maraz Corporate Finance can help. Contact our team for a no-obligation discussion.

Javier de Rojas Roca de Togores

Partner – Maraz Corporate Finance

FAQs on success and failure in mergers and acquisitions

What percentage of mergers and acquisitions fail?

Recurring estimates place the failure rate between 70% and 90%, with significant variation by buyer profile and sector. First-time acquirers fail around 77% of the time, while serial buyers with repeatable methodologies bring this down to roughly 46%. Technology sectors carry the highest risk (85-90%) owing to talent flight and obsolescence.

What is the main cause of failure in an M&A deal?

It is rarely macroeconomic; it is errors made before and after signing: superficial due diligence (behind around 31% of failures), overestimated synergies — especially revenue synergies, which are realised at only 40-50% — and, above all, poorly planned post-merger integration. Cultural friction is the most destructive intangible factor.

How is the success of a merger or acquisition measured?

Through indicators at different horizons. Short term: market reaction and operational continuity. Medium term: synergy delivery, talent retention and financial stability. Long term: ROI and sustained growth. Technically, a deal fails if the acquirer underperforms its peers over one to three years, falls short of 70% of projected synergies, or divests the asset within five years.

What is the 100-Day Plan?

It is the action plan that guides integration in the first hundred days after closing, structured in three stretches: stabilisation and risk control (days 1-30), process transition (31-60) and operating-model optimisation (61-100). Its priority is to protect the stability of the acquired business and its intangibles — customers, talent and cash flow — before undertaking transformations.

Why is M&A in the Spanish mid-market particularly complex?

Because of founder dependence (value can depreciate once the historic owner steps away), the family ownership of many targets, liquidity strains from maturing ICO loans, and the “silent death” of deals: a high share of agreements collapse weeks before signing because of accumulated friction or overly complex payment structures.