Coaching to accelerate M&A success
October 1, 2026 | Articles | Case Studies

Why Do Mergers and Acquisitions Fail? Most Often, the Answer is Leadership.

Mergers and acquisitions are among the hardest things a leadership team will ever do, and most of them do not work. In the largest study of its kind, Baruch Lev of NYU Stern and Feng Gu of SUNY Buffalo analyzed roughly 40,000 acquisitions over 40 years and found that 70–75% fail to increase sales, reduce costs, or create shareholder value. What breaks is rarely the financial model. More often, it’s the integration. And, integration runs through the people at the top of it.

The research on why is remarkably consistent. Global surveys of M&A professionals and HR leaders find that culture problems are a leading reason deals miss their financial targets, and that those problems often sit inside the executive team.

Post-merger integration succeeds or fails on whether the executive team can align quickly, communicate a future state the organization believes, and behave consistently enough that two legacy cultures start acting like one. AIIR recently partnered with a large telecom company to address these success factors head-on and accelerate the success of its post-merger integration.

What Aggregate Data Revealed: 16 Leaders Converged on the Same Development Agenda

When leaders set development goals, they work with their coaches to map each goal to the 45 leadership skills in the AIIR® Leadership Framework. While individual sessions stayed private, aggregating anonymized goal data and structured coach observations across all sixteen engagements revealed real-time insights about the skills leaders were prioritizing through the merger, especially when compared to our global benchmark.

A chart of development goals prioritized by leaders driving post-merger integration through an M&A.

Executive coaching and leadership development priorities across AIIR Consulting's global benchmark

Setting Vision and Communication Were the Top Skills

Leaders and their coaches associated 21% of coaching goals to Setting Vision (+12 points above the global benchmark) and 21% to Communication (+7 points above the global benchmark).

Setting Vision — establishing and communicating a clear and compelling future state, usually connected to organizational advances, and reinforcing it over time.

Communication — clearly conveying thoughts, feelings, ideas, and expectations, verbally and nonverbally, across methods.

Together, these skills describe the primary task of a c-suite leading through any organization-wide change: to establish the desired future state of the organization, then to communicate that future state to the organization in a clear and compelling way.

Five Skills that Support Driving Change

Each of the below skills supports a leader in credibly driving change. Each is notable because they appeared among the most-developed skills in this cohort, and because none are among the most-developed skills in the global benchmark.

Navigating Change — introducing and managing organizational change with clear communication, leading others through ambiguity and resistance.

Trust — conducting oneself so that others read reliability and an intention to do the right thing.

Listening — taking time to see another’s perspective in a way that leaves the other person feeling understood.

Accountability — accounting for one’s own actions and results transparently, and setting that expectation for others.

Team Leadership — enabling people to work together to produce value beyond what they could achieve individually.

A Leadership Population Committed to their Development

The AIIR® Leadership Framework defines Self Awareness as an understanding of the characteristics, motives, and emotions that influence your behavior and decision making. Self Awareness was the third-most developed skill in the cohort (15%). This finding was significant for two reasons:

First, it signals a cohort willing to examine how it leads when the easier move would have been to focus on driving the integration plan. Coach feedback reinforced the same picture: an organization that treats leadership capability as a business input rather than a benefit.

Second, in their feedback, coaches consistently described a culture of commitment, grit and a willingness to do what it takes. In the crucible of a merger, that culture can tip leaders into burnout and, eventually, derailment. Self Awareness is protective in these cases. Leaders who understand their strengths and weaknesses, and how they show up under pressure, are less likely to derail.

The Results: Every Leader Surveyed Reported Progress. The Business Is Starting to Show It.

Among the leaders surveyed, 100% reported gaining new knowledge and skills, making progress on their development goals, improving their performance, and applying what they learned on the job, earning the program a perfect 100 Net Promoter Score (NPS).

Leader Effectiveness

The proportion of leaders who reported improving landed above the global benchmark on nine of the 12 Leadership Dimensions in the AIIR Leadership Framework, including full marks on Driving Change, Strategic Leadership, and Visioning — muscles a successful merger asks leaders to build.

Business Impact

That development is starting to show up in the business, too. Every leader surveyed pointed to a positive impact on their team’s performance, well above AIIR’s benchmark of 78%, alongside self-reported gains in employee engagement, operational efficiency, and productivity.

Over the same period, the company’s share price rose 48% across the first year after the merger closed. In an environment where 70–75% of acquisitions fail to increase sales, reduce costs or create shareholder value, that is a notable first year.

Share price is not a direct outcome of coaching. But the leaders accountable for driving the post-merger integration were supported while they did it, and that support empowered them to lead through one of the most challenging moments of their careers.

A Powerful Lesson that Transfers to Any Team Leading Through Change

A merger is only the sharpest version of a problem that every disruptive change creates. The top of the house is asked to hold ambiguity, make irreversible calls and model a culture that does not yet exist — all while the rest of the organization reads them for the signal. M&A, a carve-out, a restructure, a new operating model or a market that shifts overnight: the constraint is the same. Alignment and capability at the top set the ceiling for everything beneath them.

Want to learn more about how AIIR Consulting supports leaders through M&A, post-merger integration and other moments of change and uncertainty? Contact us today.

About The Authors

Megan Marshall, Managing Partner

Megan Marshall is a Managing Partner at AIIR Consulting, where she partners with global organizations to build stronger leaders, more cohesive teams, and cultures that drive performance. Known for her sharp insight and presence in the room, Megan brings deep expertise in executive coaching and organizational development. She holds a Master’s in Talent and Organization Development and Executive Coaching from the McColl School of Business at Queens University. Connect with Megan