How to Onboard Employees in Mergers and Acquisitions?

The Human Side of M&A Success

Mergers and acquisitions (M&As) are high-stakes endeavors that hinge not just on financials, but on people. In 2021 alone, a record-breaking 60,000+ M&A deals were struck globally. Yet, research consistently shows that 50–90% of M&As fail to deliver expected value. A critical reason is neglecting the human factor, mismanaging people and clashing cultures accounts for roughly two-thirds of failed deals. Employees from an acquired company often feel uncertainty, and without a thoughtful onboarding strategy, companies risk a talent exodus that can derail the merger’s goals. In fact, one study found that within the first year post-acquisition, companies retained only about 66% of the acquired employees versus 88% of their regular hires. These sobering statistics underscore that effective employee onboarding in M&A is not a mere formality, but a strategic imperative. By focusing on welcoming, integrating, and engaging employees during a merger or acquisition, HR leaders and business owners can vastly improve retention, morale, and ultimately the success of the deal. This article explores how to onboard employees in M&As, offering best practices and real-world insights to ensure a smooth transition for all involved.

Onboarding is critical to retaining talent and realizing deal value in mergers and acquisitions. When two companies combine, the employee experience during integration can make or break the deal’s success. Onboarding sets the tone for how acquired employees perceive the new organization. If done poorly, uncertainty and culture shock can prompt invaluable talent to walk out the door. For example, a study by MIT Sloan found that one-third of employees at acquired companies left within the first year, a turnover rate nearly three times higher than normal new-hire attrition. Such departures can create costly knowledge gaps and operational disruption. Beyond individual exits, disengagement is a risk, if 34% of employees leave, an equal number may be quietly job-hunting or “checking out” mentally. It’s no surprise, then, that most deals struggle to achieve intended objectives when the workforce isn’t fully on board. On the flip side, thoughtful onboarding can significantly improve retention and engagement, helping preserve critical institutional knowledge and momentum. HR’s role is to ensure employees feel supported and “invited” into the new organization from day one. By investing in a robust onboarding process, companies protect their investment in the acquisition, retaining the talent and human capital that often are the very reasons for the deal.

Onboarding employees during an M&A is not the same as onboarding brand-new hires. There are unique psychological and logistical challenges that HR must address:

• Lack of Choice & Uncertainty: Unlike a new hire who chose to join the company, acquired employees never applied for this change, it was thrust upon them. They may feel anxious or even resistant, since “employees aren’t choosing to join a new company” and deserve extra care. There’s often fear of the unknown: Will their role change or be redundant? What about their benefits, team, or career path? This uncertainty can dampen morale. As one HR leader notes, you must be “very conscious, very respectful” in acknowledging that reality. Using terms like “welcome” or “invite” rather than “acquire” when referring to people is a simple but powerful shift to show respect.
  
• Workload & Change Overload: Acquired employees typically have to keep the business-as-usual tasks running in their legacy organization while going through onboarding trainings and integration meetings. Many are also called on to assist with integration projects, all of which can lead to overload and burnout. This dual responsibility, doing their regular job and absorbing a slew of changes, differs from a normal new hire who can focus solely on learning the ropes. Change management is critical to avoid overwhelming people with too many new processes at once. Savvy acquirers map out all changes and pace them to prevent “change fatigue”, sometimes even hiring temporary staff to take some load off key teams during the transition.
  
• Team Dynamics & Support: New hires usually join an established team of company veterans who can guide them informally. In a merger, entire teams might join at once, meaning an acquired employee could be surrounded by fellow newcomers with no long-tenured colleagues in their immediate circle. This can leave them without the usual support network or mentors that help integrate someone into the culture. HR should recognize this vacuum and proactively provide resources like buddies or integration ambassadors to help transferred teams navigate the new organization. Additionally, acquired employees may enter an environment with different norms (a startup team suddenly working inside a large corporation, for instance), which can create feelings of alienation if not addressed.
  
• Emotional and Cultural Barriers: Mergers often come with culture clashes, differences in values, communication styles, and work practices. Acquired staff might feel pride in their old company’s culture and apprehension about losing it. If the merger is portrayed as a “takeover,” it can foster an “us vs. them” mentality. Indeed, history has shown that disregarding cultural differences can be disastrous. One famous example is the Daimler-Benz and Chrysler merger of 1998, which failed in large part due to a severe clash in corporate cultures and lack of trust between the German and American teams. Key talent left and productivity plunged amid mutual resentment. The lesson is clear: onboarding in M&A must actively bridge cultural gaps and help employees find common ground, or the integration may falter.
  

Recognizing these challenges is the first step. HR professionals should tailor the onboarding plan, knowing that acquired employees are joining under unusual circumstances, with different motivations, concerns, and needs than a typical new hire. Next, we’ll discuss how to prepare for these challenges even before the deal is finalized.

Successful M&A onboarding starts well before “Day 1” of the new combined company. HR and leadership should be involved early in the due diligence and planning phases to set the stage for a smooth transition. Key preparatory steps include:

• HR Due Diligence: Before the merger is even signed, assess the target company’s human capital. This means reviewing org charts, roles, talent profiles, compensation and benefits differences, and any employee-relations issues. Early identification of “critical talent” is crucial, know which people or teams are essential to future success and need to be retained at all costs (perhaps via retention bonuses or special career opportunities). Also, flag any redundancies in roles or conflicts in HR policies that will need resolution. By understanding the people landscape upfront, you can avoid nasty surprises post-close and have plans ready for integration or restructuring.
  
• Cultural Assessment: “No two organizations are the same,” as KPMG notes. Take time to study the culture of the acquired company before closing the deal. What are its core values and “secret sauce” practices that employees cherish? What differences exist between the two companies’ work styles, decision-making, or employee expectations? This can be done through employee surveys, focus groups with the target’s staff, or even examining public feedback (like Glassdoor reviews) for cultural clues. If you uncover non-negotiables, for example, the acquired startup has a beloved flexible work policy, decide how you will honor or adapt these in the new organization. Integrating culture doesn’t mean one culture steamrolls the other; it means finding a respectful path that retains what people value most. Ignoring this is a “blind spot” that can derail the integration later.
  
• Integration Roadmap: Develop a high-level roadmap of how and when different parts of the organizations will come together. Often, not everything changes on Day 1. For instance, back-office functions (HR, IT, finance) might integrate first within a few months, while customer-facing teams or products phase in more slowly. Creating a timeline that spells out phases of integration helps set employee expectations and context. Importantly, decide what needs to be communicated before Day 1 (such as organizational structure, reporting lines, any immediate policy changes) and what can roll out gradually. Having this plan ensures that onboarding isn’t ad-hoc, but a coordinated effort aligned with the overall integration strategy.
  
• Onboarding Playbooks: If your company frequently engages in acquisitions, it pays to have a standardized M&A onboarding playbook. This is a template or checklist covering all the steps to welcome and integrate new employees at both the company-wide and team levels. It might include timelines for sending welcome packets, scheduling orientation sessions, IT account setups, training modules, assigning mentors, etc. While each deal will have its nuances, a playbook ensures nothing falls through the cracks and speeds up planning. Include input from various departments (IT, payroll, facilities, communications) in this playbook because onboarding acquired employees truly “takes a village” across the organization.
  

By preparing in advance on these fronts, HR can hit the ground running once the ink is dry on the merger. Early engagement and planning can significantly reduce the chaos and confusion that employees feel when changes are announced, making the eventual onboarding process more orderly and reassuring.

Open, honest, and frequent communication is the linchpin of successful onboarding during M&A. Employees crave information during times of upheaval, and if the company doesn’t provide it, they’ll fill the void with rumors and fears. Here’s how HR and leaders can communicate effectively:

• Timely, Clear Announcements: As soon as it’s feasible (often immediately after the deal is officially announced), communicate to all employees about what the merger/acquisition means for them. Even if all details aren’t sorted, address the basics: Will there be job losses? What changes (if any) are immediate? When can they expect more information? Being transparent about knowns and unknowns helps build credibility. It’s okay to say "We are still working out the details on X, and will update you by [date]." Acknowledge the elephant in the room, for example, if systems will change or teams will be restructured, rather than ignoring tough topics.
  
• Empathy in Messaging: The tone of communication should be reassuring and empathetic. As noted earlier, avoid calling people “acquisitions” or treating them as assets being absorbed. Instead, frame the change as welcoming new colleagues into a shared future. Phrases like “We’re excited to welcome the [TargetCo] team to our family” set a far better tone than “following our takeover of [TargetCo]…”. Small words matter. Also, recognize emotions: leaders might say, “We understand that change can be stressful, and some of you may be uncertain, that’s natural. We are committed to supporting everyone through this transition.” This human-centric approach signals respect.
  
• Two-Way Dialogue: Communication shouldn’t be a one-way broadcast. Provide channels for employees to ask questions and voice concerns, and ensure they get answers. Town hall meetings, Q&A sessions, and focus groups are excellent during the onboarding phase. For instance, hosting a series of meet-and-greet sessions (virtually or in person) allows acquired employees to ask leadership questions directly and meet their new colleagues. Some companies even set up integration hotlines or dedicated Slack channels where questions can be fielded in real time. The key is to listen and respond. If multiple people are asking about job security or benefits, address it in a company-wide FAQ document to quell speculation. Engaging employees in dialogue shows transparency and builds trust.
  
• Consistency and Unity in Messaging: Ensure that managers at all levels are on the same page with communications. Mixed messages are dangerous in a merger. It helps to arm frontline managers with talking points and FAQs so that when team-level onboarding happens, the information is consistent. Communicate the “why” behind the merger (the vision and benefits) in a clear narrative and repeat it often, people need to hear a message several times to absorb it, especially when distracted by day-to-day workloads. Consistent, positive messaging about the merger’s goals and the value each person brings to the combined company can gradually turn skepticism into cautious optimism.
  

In summary, be honest, be human, and keep the lines of communication open. By proactively managing the narrative and addressing concerns, you prevent misinformation and help employees feel respected and informed, a vital foundation for all other onboarding efforts.

“Culture eats strategy for breakfast,” as the saying goes, and nowhere is this more evident than in mergers and acquisitions. Bringing together two companies means bringing together two sets of values, norms, and work cultures. Thus, a core part of onboarding in M&A is intentionally merging cultures and aligning values. Some strategies include:

• Acknowledge and Respect Differences: Right from the start, recognize that each organization has unique cultural strengths. In the due diligence phase, identify the most cherished aspects of the acquired company’s culture, the “secret sauce” practices or values that employees are proud of. Wherever possible, preserve or honor these elements in the new combined culture. Perhaps the acquired firm has a highly agile startup vibe or a tradition of monthly team lunches; such practices can be kept or even spread to the rest of the company. This signals to incoming employees that their identity isn’t being erased. As a positive example, Tata’s 2008 acquisition of Jaguar Land Rover was lauded as a cultural success largely because Tata respected JLR’s established British culture and kept its local management in place, rather than imposing an entirely new way of working. That respect built trust, which smoothed the integration.
  
• Define a Shared Vision and Values: Work on creating a unified mission, vision, and set of values for the combined company, and involve employees from both sides in that process if possible. If the two companies’ stated values are similar, it might be a matter of showing how they align. If they differ, leadership should explicitly decide what the new guiding principles will be, and communicate them. Make it clear that the culture is evolving into “the best of both worlds,” not one culture dominating the other. Integrating things like recognition programs can help reinforce these shared values, for instance, publicly acknowledging employees (from either side) who exemplify the new organization’s values can unite everyone around common ideals. Culture alignment should be woven into onboarding sessions, training, and internal communications from day one.
  
• Cultural Orientation & Training: Treat culture as a key component of onboarding content. In addition to the usual HR policy orientations, include sessions that educate all employees on the heritage and stories of each company, the rationale behind decisions, and the expected cultural norms going forward. For example, workshops or seminars on “Our New Culture and Values” can help employees understand each other’s working styles. Encourage cross-pollination, maybe have a panel of legacy employees from both companies share experiences, or run team-building activities mixing groups from the two sides. The goal is to break down “us vs. them” silos as early as possible and foster a sense of one team. Some organizations create cross-company buddy or mentor programs pairing an employee from the acquiring company with one from the acquired company to accelerate mutual understanding.
  
• Address “Culture Shock” Proactively: Despite best efforts, some friction is inevitable. Be on the lookout for signs of cultural clash, declines in morale, increased conflicts, or turnover in certain teams. Survey employees at intervals (30/60/90 days) to gauge how they’re feeling about the new environment. If issues are flagged (e.g., “I feel the new company is too bureaucratic” or “We miss the old company’s traditions”), address them openly. Sometimes small gestures can help, like reintroducing a dropped tradition or clarifying the reasons behind certain corporate practices. Remember that in many failed mergers, it wasn’t the business model that failed but the inability to mesh cultures. One data point shows 60% of acquiring companies later regretted not dedicating more resources to culture and change management during integration. Don’t fall into that trap, invest time and effort in cultural integration as a core workstream of onboarding.
  

In essence, think of cultural integration as a critical part of onboarding, not an afterthought. By valuing the people and practices from both sides and crafting a thoughtful culture strategy, you increase the odds that employees will feel a sense of belonging in the new organization rather than feeling like outsiders. This, in turn, boosts retention and performance.

Now that we’ve covered preparation, communication, and culture, let’s drill down into concrete onboarding best practices during mergers and acquisitions. These practices, drawn from HR experts and case studies, can help ensure acquired employees (and existing ones) are supported throughout the transition:

1. Start Before Day One (Pre-boarding): Don’t wait until the deal formally closes to begin onboarding activities. Whenever legally and logistically possible, involve incoming employees early. This could mean sending welcome information and introductions in the weeks leading up to their official transfer. Preparing IT accounts, equipment, and workspace for them in advance also shows that the organization is ready and excited for their arrival. Onboarding truly “starts before the employee does,” as one HR executive put it. Early preparation across teams (IT, HR, managers) ensures that basics like email access, org charts, and first-week schedules are ready, preventing a chaotic Day One.
   
2. Cascade Onboarding at Multiple Levels: Plan onboarding not just at the company-wide level, but also for each function and team. Often, organizations focus on a general orientation, overview of the company, HR policies, benefits, etc., which is important, but not sufficient. Ensure that each acquired employee also gets a tailored onboarding within their specific department or role. For example, the Finance team from the acquired company might need sessions on the new financial systems and reporting structure, while engineers might need a deep dive into the new tech stack. Slalom Consulting calls this “cascade onboarding,” meaning a structured process across all levels. Provide checklists or guidelines to managers for integrating new team members into existing workflows. This multi-layered approach prevents employees from feeling lost once high-level orientation is over, as they will continue learning in context with their peers and tasks.
   
3. Develop a Detailed Integration Roadmap: As mentioned earlier, give employees a transparent schedule of how the integration will unfold. For instance, communicate which systems or policies will change and when. “Not all functions are integrated at the same time,” notes one best-practice report, so let people know the plan (e.g., “Sales teams will merge in Q3, IT infrastructure by Q4,” etc.). This roadmap can be shared as part of onboarding materials. It provides context and reduces anxiety by eliminating the fear of sudden surprises. Employees can mentally prepare for upcoming changes if they know the timeline. It also demonstrates that leadership has a methodical plan, instilling confidence.
   
4. Extend the Onboarding Timeline (“Long-boarding”): In an M&A scenario, onboarding is not a one-day or even one-week affair, it’s a months-long journey. Many experts suggest treating the first 100 days (or even the first 6 months) as the onboarding period for acquired staff. Set expectations accordingly: unlike a normal new hire who might be fully ramped up in a month, an acquired employee may take longer to find their footing because the entire organization around them is shifting. Plan touchpoints over an extended period. For example, conduct a 30-day check-in, a 60-day town hall, a 90-day survey, etc. to continually guide and gauge how employees are settling in. A longer onboarding horizon allows you to address issues as they arise and reinforce key messages multiple times. It’s about persistence and patience, giving people space to adapt while keeping support structures in place.
   
5. Leverage Technology for Efficiency: During an acquisition onboarding, there’s a mountain of paperwork and logistics, from transferring employee data to setting up payroll, benefits enrollment, new email domains, and so on. Automate and streamline as much of this administrative work as possible. HR leaders note that by automating routine tasks (like digital forms for HR paperwork, online training modules, etc.), they freed up 10% or more of their workload, equivalent to several full-time staff’s work, which they could reinvest into personal interactions. Use a good HRIS or onboarding software to handle the bulk of form-filling, e-signatures, and process tracking. This ensures consistency and frees your HR team to focus on the human side: answering individual questions, hosting welcome events, and listening to feedback. Essentially, let tech handle the mundane so humans can handle the meaningful.
   
6. Personalize the Experience (Empathy & Support): Acquired employees are likely to have diverse feelings, some may be excited about new opportunities, others mourning the loss of their old company’s identity. Tailor onboarding to show empathy and personal care. Managers should have one-on-one meetings early with each team member to understand their concerns and career goals in the new setup. Consider assigning a “buddy” or mentor to each incoming person, ideally someone from the acquiring company who can help decode acronyms, make introductions, and serve as a go-to for questions. Also, try to build social connections: for example, Nancy Hauge (a seasoned Chief People Officer involved in 30+ M&As) makes a point to ask who each employee’s best friend was in their former workplace, and then finds ways to help them make new friends in the merged company. Facilitating new collegial relationships (e.g., through team lunches, buddy systems, or group projects) helps the newcomers “stick” and feel less alone. The overarching principle is to demonstrate care: show employees that the company sees them as individuals, not just positions to be shuffled around.
   
7. Leadership Involvement and Inclusion: Keep the acquired company’s leaders involved in the onboarding and integration planning. When you include managers and leaders from the acquired side in designing the onboarding process, it sends a strong message of unity and respect. These leaders can champion the change among their teams and provide valuable input on what their employees need. They are also likely going through the transition themselves, so giving them a role helps maintain their engagement. More broadly, visible executive support is key: senior leaders of the acquiring firm should be actively present in onboarding events, whether it’s the CEO hosting a welcome town hall or VPs sitting in on orientation sessions to answer questions. Consistent, unified leadership presence helps reinforce the message that “we’re all in this together” and that the company is investing in its people. It also gives employees confidence that the integration is being taken seriously at the highest levels.
   
8. Provide Training & Support Resources: Mergers often require employees to learn new systems, processes, or even regulations. Offer plenty of training opportunities, and be patient as people climb the learning curve. This might include formal training sessions on new software, informational guides, or a helpdesk to assist with IT issues. Some organizations set up a dedicated support hotline for acquired employees during the first few months. For instance, if the acquired team must transition to the parent company’s CRM or HR portal, having a helpline staffed by IT or peers (including some of the acquired company’s own IT folks who understand the old systems) can significantly reduce frustration. Additionally, create FAQs and knowledge bases that employees can reference 24/7 for common queries (like “How do I enroll in the new benefits?” or “Where do I find policy X?”). The easier you make it for people to get help, the faster they’ll acclimate.
   
9. Listen and Adapt: Finally, treat onboarding as a two-way street, gather feedback and be ready to adjust your approach. Set up “listening posts” such as pulse surveys at 30, 60, 90 days, regular check-ins, or an online forum for feedback. Watch metrics like turnover rates, internal helpdesk queries, and even productivity or customer satisfaction indicators for any red flags of integration issues. If certain teams are experiencing higher turnover, dig in to find out why, maybe there’s an unaddressed concern or a manager struggling with the new structure. By monitoring sentiment and behavior, HR and leaders can respond quickly (for example, clarifying a miscommunication, providing extra training, or in some cases slowing down the pace of change if it’s too overwhelming). Remember that onboarding in M&A is iterative, you might not get everything perfect initially, but by listening to employees you can continuously improve the experience. This responsiveness also shows employees that the company cares about their input, further building goodwill.
   

Implementing these best practices can significantly smooth the turbulence that often comes with mergers. A shining illustration of doing it right comes from Adswerve, a marketing firm, after it acquired Liquidbox. Adswerve’s HR team didn’t rush to force a full integration overnight; instead, they laid out a gradual transition over two months, clearly communicating what changes to expect when, and giving the small acquired team (23 people) time to adjust. The result? They retained every single employee through the first year post-acquisition, a remarkable outcome in contrast to typical attrition statistics. This case reinforces that with careful planning, empathy, and structured onboarding, companies can turn what is often a vulnerable period into a success story.

In any merger or acquisition, flashy headlines tend to focus on the financials or strategic rationale. But as this discussion illustrates, the real integration happens in the hearts and minds of people. Onboarding employees in an M&A is about building a bridge from “what was” to “what will be,” and walking people across that bridge with guidance and care. HR professionals and business leaders serve as the architects and guides in this journey, aligning processes, communicating vision, merging cultures, and easing individual transitions. When done well, onboarding becomes the bedrock for a new, unified organization where employees feel valued and motivated to contribute. It can prevent the costly loss of talent and momentum that plagues so many mergers. Conversely, if the human element is overlooked, even the most promising deal can falter under the weight of disengagement and culture clash.

The takeaway is simple: put people at the center of your integration strategy. From pre-merger planning through the first year post-merger, prioritize clear communication, empathy, training, and inclusion. Celebrate small integration wins and openly address challenges, this builds trust. Remember that each employee who joins through an acquisition is essentially a new hire you didn’t personally court; you must win their trust and commitment through your actions. As one HR leader insightfully noted, “The whole point of onboarding [after an acquisition] is to say, ‘Look, there’s a spectacular future out there, and it’s even better because we’re together’.” By conveying that optimistic vision and backing it up with a supportive onboarding experience, you set the stage for your merger not just to combine companies on paper, but to truly unite people. And when people unite behind a common purpose, the chances of achieving the deal’s full potential increase dramatically.

FAQ

What makes onboarding during mergers and acquisitions different from regular onboarding?

Onboarding in M&A involves integrating employees who did not choose to join the new company, often amid uncertainty, cultural changes, and workload pressures. Unlike regular new hires, they must adapt while continuing their existing responsibilities and navigating significant organizational shifts.

How can companies prepare for employee onboarding before an M&A deal closes?

Pre-merger preparation includes HR due diligence to assess talent and benefits, cultural assessments to identify valued practices, integration roadmaps to set timelines, and creating onboarding playbooks to standardize processes.

Why is communication so important during M&A onboarding?

Clear, empathetic, and timely communication reduces uncertainty, builds trust, and prevents rumors. Companies should provide consistent messaging, acknowledge employee concerns, and create two-way channels for questions and feedback.

What strategies help merge company cultures after an acquisition?

Effective cultural integration includes respecting existing cultural strengths, defining shared values, providing cultural orientation sessions, and proactively addressing potential culture shock through surveys and team-building initiatives.

What are the best practices for onboarding employees during M&A?

Key practices include starting onboarding before Day One, cascading onboarding at company and team levels, extending onboarding over several months, using technology to streamline admin work, personalizing the experience, involving leadership, providing training, and gathering feedback to adapt processes.