What Boards Get Wrong About M&A — And Why It Keeps Costing Them
By Alton Davis
The deal looks clean on paper. The financials have been stress-tested, the synergies modeled, the purchase price negotiated down to the basis point. The board approves. Management celebrates. And then, somewhere between signing and the eighteen-month mark, the value starts leaking.
It leaks through attrition among the exact talent the deal was designed to retain. It leaks through productivity loss while two organizations figure out whose processes, whose culture, and whose leadership norms are going to survive. It leaks through the quiet exodus of institutional knowledge that no integration playbook anticipated because no one thought to look for it during due diligence.
This pattern is not an anomaly. Study after study over three decades of M&A research has put the failure rate of mergers and acquisitions — defined as transactions that fail to deliver their projected value — somewhere between 50% and 70%. The financial modeling gets more sophisticated every year. The failure rate does not improve.
The reason is not financial. It is human. And boards, as currently constituted, are not governing the human dimension of M&A with anything close to the rigor they bring to the financial one.
What Gets Measured Gets Managed — And This Goes Unmeasured
Walk through the typical board-level M&A approval process and you will find exhaustive documentation on financial projections, market position, regulatory exposure, and integration cost assumptions. You will find sparse documentation — if any — on the human capital risks that will determine whether those projections are ever realized.
How compatible are the two leadership cultures? What is the voluntary attrition risk among key talent in the target organization, and what assumptions has management made about retention? How long will it realistically take for two organizations with different operating norms to function as one? What is the cost, in productivity terms, of the distraction that accompanies any large-scale integration — and has that cost been modeled into the synergy timeline?
These are not soft questions. They are financial questions in human clothing. And the fact that most boards do not ask them with the same precision they bring to working capital adjustments is one of the primary reasons M&A continues to destroy value at the rate it does.
The human capital due diligence gap is the most expensive blind spot in corporate governance.
Three Specific Places Value Leaks
In two decades of leading HR through large-scale M&A activity across financial services, consumer goods, and commercial real estate, I have watched value leak from the same places repeatedly. Boards that govern M&A effectively learn to anticipate all three.
The leadership assimilation gap. Every acquisition brings two leadership teams into contact — and the friction between them is almost always underestimated. The acquiring company’s leaders assume cultural authority that the acquired company’s leaders are not prepared to cede. Role ambiguity proliferates. Decision-making slows. The talent the deal was designed to capture — typically the senior operators with the deepest relationships, the institutional knowledge, and the capabilities the acquirer was paying for — begins evaluating their options.
The standard retention mechanism is a financial holdback: a cash incentive tied to remaining employed for twelve to twenty-four months post-close. These instruments are necessary but not sufficient. They retain bodies; they do not retain engagement. A senior executive who has decided to leave will leave at the twelve-month mark with the retention bonus in hand, having contributed a fraction of the value they were retained to provide.
What actually retains key talent is clarity — about their role, their authority, their future in the combined organization, and the cultural norms they will be expected to operate within. Providing that clarity is a leadership responsibility that boards should be holding management accountable for, starting before the deal closes.
The cultural due diligence gap. Financial due diligence is a rigorous, standardized process. Cultural due diligence, where it exists at all, is typically a series of leadership interviews conducted by the deal team with no consistent framework and no baseline to compare against. The result is that the acquiring company often does not discover the true cultural character of the target — its actual operating norms, its real decision-making patterns, the unwritten rules that govern how work actually gets done — until well into the integration, when changing course is expensive and disruptive.
Culture is not what an organization says it values. It is what it tolerates, what it rewards, and what it punishes. A target company that presents well in management presentations may have deeply embedded behaviors — around accountability, around risk-taking, around how dissent is handled — that are fundamentally incompatible with the acquirer’s operating model. Discovering this after close, rather than before, is a governance failure with a financial cost.
Boards should be asking: What is our cultural due diligence process? How do we assess compatibility, not just capability? And who is accountable for the integration of cultures, not just the integration of systems and structures?
The synergy timeline fallacy. Synergy projections are almost universally built on assumptions about how quickly two organizations will operate as one. Those assumptions are almost universally optimistic. The reason is straightforward: synergies are modeled by financial analysts; the friction that delays them is generated by human beings navigating uncertainty, competing for position, and protecting institutional turf.
A $120M cost savings projection built on a twelve-month integration timeline that actually takes twenty-four months is not a $120M opportunity. It is a significantly smaller one, net of the carrying costs, the productivity loss, and the talent attrition that occurred while the timeline slipped. Boards that accept synergy projections without interrogating the human capital assumptions embedded in the integration timeline are approving numbers that are unlikely to materialize on schedule.
What Effective Board Oversight Looks Like
The goal is not for boards to become integration managers. That is management’s job. The goal is to govern the human capital dimension of M&A with the same discipline applied to the financial one.
In practice, that means four things.
Human capital due diligence should be a board-level disclosure. Before approving a transaction, the board should receive a structured summary of the human capital due diligence conducted — covering cultural compatibility assessment, key talent retention risk, leadership assimilation plan, and the human capital assumptions embedded in the synergy model. If management cannot produce this document, that is itself a material finding.
Retention risk should be quantified, not assumed. The board should know specifically which roles and individuals are considered critical to value realization, what the assessed risk of losing them is, and what mechanisms are in place beyond financial holdbacks to retain their engagement. This is not a request for an org chart. It is a request for a risk-adjusted view of the human capital on which the deal thesis depends.
Integration milestones should include people metrics. Post-close reporting to the board typically focuses on financial integration milestones — systems consolidation, cost reductions, revenue synergies. People metrics — voluntary attrition among retained talent, engagement scores in the acquired organization, time-to-productivity for combined leadership teams — should appear on the same dashboard. If they are not being tracked, they are not being managed.
The CHRO should have a direct line to the board during integration. The human capital risks of M&A are too consequential to be filtered entirely through the CEO. The most effective integrations I have been part of have involved direct communication between the HR leadership and the board’s Human Capital or Compensation Committee — not to circumvent management, but to ensure the board has an unmediated view of cultural and talent dynamics that management may not be positioned to report objectively on itself.
The Fiduciary Case
Directors have a fiduciary responsibility to protect enterprise value. In the context of M&A, that responsibility cannot be discharged by approving a financial model without governing the human assumptions on which it depends.
The deals that destroy value do not fail because the financial analysis was wrong. They fail because the people variables — culture, leadership, talent retention, organizational alignment — were treated as implementation details rather than governance imperatives.
Boards that close that gap will not eliminate M&A risk. But they will make materially better decisions about which transactions to pursue, at what price, on what timeline, and with what governance oversight during integration. In a landscape where the majority of deals still fail to deliver their projected value, that is a meaningful competitive advantage.
The financial due diligence is already rigorous. It is time the human capital due diligence caught up.
Alton Davis is a senior executive and board advisor with two decades of Fortune 500 leadership across consumer goods, financial services, and commercial real estate. He has led HR through large-scale M&A integration at L’Oréal, The Hershey Company, AIG, Freddie Mac, and Cushman & Wakefield, and focuses on Compensation Committee and Human Capital Committee roles where human capital strategy, M&A risk, and enterprise value intersect.
