Post-Acquisition Integration: How to Unite Processes and Win Buy-In from Legacy Teams

Erin McCormick
Jun 16
3 min read

Mergers and acquisitions are a sign of growth, but integration is where the real work begins.

Once the ink is dry, you need to combine systems and staff, align cultures, protect the client experience and build trust in the new way forward. Unfortunately, this is where many firms falter. Processes become fragmented, legacy teams cling to what they know and clients sense the disconnection.

To succeed post-acquisition, you have to be deliberate about unifying operations, communicating and engaging people early and often. So let’s explore what works and what doesn’t when bringing people and processes together.

One firm or many? When to standardize vs. remain flexible

There’s no one-size-fits-all answer to post-merger operations, but most firms wrestle with whether to enforce a single firmwide way of working or allow legacy offices to keep their own systems.

In general, we recommend standardizing technology and processes across the firm. A unified approach improves internal coordination and capacity, reduces training overhead and ensures a consistent client experience. When every team uses the same billing platform, engagement letter templates and workflow tools, it’s easier to track progress and maintain quality.

But standardizing too quickly can cause friction if the acquired firm is deeply embedded in its technology and processes.

That’s why many firms start with a phased plan. They prioritize unifying processes that directly impact the client experience, like billing, scheduling and service delivery timelines, but leave room for flexibility in less critical areas—at least during year one.

Earning buy-in from skeptical teams

Legacy team members didn’t ask to be acquired. Many are wary and concerned about losing autonomy or being micromanaged.

Be intentional about earning trust to bring legacy teams along. Here are some ways to do just that:

Lead with transparency. Uncertainty breeds resistance. Communicate early and often about what’s changing, why it’s happening and how you plan to support team members. Empower managers with talking points so they can confidently answer questions.
Treat legacy employees with the same care and attention as new hires. That means onboarding them intentionally with culture, values and client service expectations. If you treat them like outsiders, they’ll act like outsiders. But if you welcome them like new team members, they’ll act like part of the team.
Give people a voice. Ask questions. Solicit feedback. Listen to what’s working and what’s not. Create safe channels for honest input. Regular integration check-ins or pulse surveys can help you identify friction points before they fester.
Celebrate shared wins. When clients renew under the new firm brand, hit a milestone or share positive feedback, highlight it. Shared wins reinforce the message that the new approach works and everyone plays a role in delivering results.

Protecting the client experience during integration

In the scramble to align internal systems, client experience (CX) is often an afterthought. That’s a costly mistake.

Firms that excel post-acquisition treat CX as a strategic initiative rather than a checkbox. They include it in their one-page strategic plan, assign clear ownership and track performance metrics to ensure continuity and satisfaction.

Client-focused integration strategies include:

Proactive communication. Let clients know about the acquisition before they hear it elsewhere. Explain what’s changing, what’s not and who they can contact with questions.
Consistent access. Don’t disrupt relationships. Ensure clients still have access to the people they know or introduce new contacts in a warm, personal way.
Billing and reporting continuity. Invoicing errors or delayed reporting erode trust. Prioritize system integration in these areas and test before launch.
Feedback loops. Ask clients how they’re experiencing the transition. Are they confused? Frustrated? Pleased? Use this input to make real-time adjustments.

If clients start calling asking about their invoices or saying they don’t know who to talk to, you’ve already failed.

Integration is a leadership test

Firms that thrive post-integration don’t wait until after the deal closes to think about systems, people or client communications. They identify influential team members from both sides of the deal who can model collaboration and help rally others.

If you’re leading your firm through integration, start with a clear plan, assign accountability and above all, keep your clients and your people at the center.

Do you want to connect with other Managing Partners in the accounting profession to improve performance and grow your firm?

The Boomer Managing Partner Circle is a peer group of Managing Partners from successful and growing firms. Apply now to gain a network of trusted peers to call on as you shape your firm for the future.

As the Member Experience Strategist of Project Management for Boomer Consulting, Inc., Erin McCormick plans, organizes, secures and manages resources for the firm’s many service and program areas, including providing assistance and constant communication with clients and sponsors and serving as an even liaison. Her primary duties include overseeing and managing the specifics of all Boomer Consulting, Inc. communities, such as the Boomer Technology Circles, CIO Circle, Managing Partner Circle, Business Transformation Circle and Operations Circle.