This is one of two articles on achieving postmerger synergies. For a discussion of early actions to plant the seeds of synergy success, see the companion article, “Planning for Synergies Should Start Sooner Than You Think.”
In M&A, synergy capture depends on translating the right ambition into disciplined execution. Some companies lose momentum during post-merger integration (PMI): plans remain theoretical, cross-functional tensions slow progress, and synergies fade into missed expectations. By contrast, leading acquirers are equipped with practical tools and proven methods that turn synergy promises into measurable outcomes.
Our work with integration leaders highlights four essentials that distinguish top performers: they use an iterative approach to integration planning, moving from stretch targets to detailed executable plans; they deploy clean teams to accelerate planning in sensitive areas; they pursue revenue synergies as rigorously as cost savings; and they track performance with precision. Together, these practices provide the visibility and structure needed to sustain momentum and deliver results that both the organization and the market can trust.
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Rapidly Iterate on Targets Using Stage Gates
To succeed in reaching targets, leading acquirers use a robust and practical “W” approach. (See Exhibit 1.) It combines rapid, top-down stretch-target setting with two rounds of bottom-up validation that enable progressively greater degrees of accuracy and detail as the process advances through setup, design, and planning. The approach allows companies to stretch to the most ambitious, yet still feasible, extent. All groups with a role in integration are involved—from the integration management office (IMO) to the integration planning teams.
At the outset, the steering committee and IMO establish ambitious, top-down synergy targets, informed by due diligence findings, clean-team analyses, and strategic priorities. These high-level targets are then tested and refined through bottom-up analysis by business unit and functional leaders—the people with skin in the game who will ultimately deliver the results.
Typically, the bottom-up estimates are iterated through stage gates that filter out weak or unviable initiatives. (See Exhibit 2.) Stage gate 1 begins with high-level synergy ideas. As they progress, initiatives must demonstrate increasing feasibility and a greater confidence in the return on investment. By stage gate 3, they are fully vetted, credible, and approved for implementation. This structure prevents planning teams from pursuing initiatives that lack a clear path to value. It also builds accountability by requiring sign-off from leaders who own delivery, as well as from the steering committee. At stage gate 4, approved initiatives are implemented, incorporated into budgets, and tracked against the plan, while stage gate 5 marks the point when impact begins to accrue.
The W approach offers two additional advantages. First, it allows senior leaders to see which teams can pick up the slack when another team falls short, ensuring that the deal’s overall synergy targets are met. Second, it breaks down silos by fostering cross-functional dialogue. Specifically, the process ensures that any cross-functional dependencies between integration team initiatives are identified centrally via the IMO, which can then apply its cross-organizational perspective to resolve conflicts. For example, a global sourcing team’s procurement savings plan may depend on the IT team prioritizing a database software upgrade ahead of other projects, such as its own global ERP simplification plans. In such cases, the IMO can address any alignment issues early.
A US-based global manufacturer, targeting $4 billion in cost savings from a merger, applied the W approach over several months. Each business unit submitted increasingly specific synergy data: initial idea lists with likelihood assessments, followed by quantified ranges, key assumptions and risks, and, finally, detailed costs (one time and ongoing). The IMO worked with the CFO to validate each submission, verify whether the targets were on track and supported the company’s strategy, and adjust and reallocate targets where necessary. Because synergies were developed within the context of each unit’s operating model, these plans became integrated business roadmaps, not isolated cost-cutting exercises. This was a big plus, considering that synergies would need to be an integral part of the company’s future operations.
The top-down, bottom-up nature of the approach fostered transparency and alignment throughout the company’s vast managerial ranks and across dozens of business units, R&D, and finance teams. And because the submissions took place within the normal review process, they served as a business plan review, helping the business leaders stay aligned with the overall planning process.
Use Clean Teams to Accelerate Planning in Commercially Sensitive Areas
Regulatory restrictions prohibit gun jumping: the sharing of commercially sensitive information before a deal closes. These restrictions often lead companies to believe they must delay integration planning in certain areas, which can cost them precious time and cause disruptions later on. Clean teams offer a proven way to work within these rules while still making rapid progress.
A clean team is an independent group comprising third-party specialists and/or employees who can be reassigned from their current role if the deal falls through. With management’s guidance, the team collects and analyzes sensitive data before closing. Bound by strict legal protocols agreed upon by both companies’ legal departments, it operates behind a firewall to ensure confidentiality.
Clean teams can review a broad range of information, including customer data (pricing, volumes, profitability, and marketing plans), supplier data, product performance, and R&D pipelines. With legal approval, they deliver aggregated, sanitized findings to management. Thus, clean teams allow companies to plan for synergies (particularly procurement savings, R&D savings, and commercial opportunities) faster and to assess risks in areas where sensitive data cannot yet be legally shared between the companies.
Not all planning needs to run through clean teams; overreliance can dilute accountability. The best practice is to keep most planning within functional teams to ensure organizational ownership, reserving clean teams for those commercially sensitive topics that are most critical to the transaction. Typical high-value areas include:
- Procurement: analyzing supplier overlaps and spend cubes to prepare for renegotiations during the post-close window when supplier relationships are being reset
- Customers: mapping overlaps, developing customer migration strategies, and preparing factbooks for sales teams to help minimize customer disruption on day 1; evaluating, sizing, and prioritizing revenue synergy opportunities, such as cross-selling, to develop detailed, actionable plans and inform go-to-market and sales enablement strategies and plans
- Products: identifying differences in product pricing or product development roadmaps to help design harmonization plans after the closing
Clean teams are particularly useful in helping companies with three core integration activities: compiling a wide range of baseline data, vetting synergy targets, and preparing options for key decisions even before the deal closes.
Over the past decade, clean teams have become even more essential. Antitrust scrutiny has intensified, and regulatory reviews for major transactions can now stretch beyond a year. Enforcement is also tougher. For example, the European Commission can impose fines up to 10% of revenue for gun-jumping violations. The commission levied this maximum amount on Illumina for closing its acquisition of Grail without securing approval.
The merger of two European machinery companies with many overlapping products provides an example of the effective use of clean teams. After the merger announcement, some customers, worried about product continuity, slowed their purchases. To address this concern early, executives formed a clean team to compare portfolios and recommend which products to keep and which to discontinue after the deal closed. With these decisions ready by day 1, the merged company was able to reassure customers immediately and limit attrition. Without the clean team, it would have taken three months to provide the same clarity—enough time for competitors to lure customers away.
Pursue Revenue Synergies as Diligently as Cost Synergies
In many mergers, revenue synergies are discussed in the boardroom but rarely pursued with rigor. They represent the additional income generated as a direct result of the merger, beyond what the two companies would have achieved independently. Common sources of revenue synergies include:
- Cross-selling products and services to each company’s customers
- Jointly developing new offerings
- Leveraging combined go-to-market capabilities to expand market access
- Entering new geographies
- Coordinating net revenue management
Whereas cost synergies—such as those arising from consolidating overhead or leveraging procurement scale—are relatively easy to identify and track, revenue synergies tend to be viewed as harder to distinguish from the normal flow of business. They often lack a clear baseline, making it difficult to attribute gains (or losses) directly to integration initiatives. Without disciplined planning and monitoring, leaders are left guessing: Did revenue increase because of synergy actions, broader market growth, or simply a strong existing sales team? And if sales declined, was it because synergies fell short—or because the base business was struggling?
Additionally, because revenue synergies are often defined at a high level, investors place less value on them, and acquirers find it harder to “bank” them as reliable, realizable gains. But they can be captured with the same rigor as cost synergies if approached systematically.
In deals with revenue synergy potential, management should establish a revenue baseline during integration planning—effectively, the premerger revenue forecast absent the deal. Integration teams can then identify concrete synergy opportunities and design specific initiatives to capture them.
Sales leaders play a central role in ensuring that these synergies are realized systematically—through initiatives such as training on new products and customer segments, implementation of holistic KPI tracking (including lead generation), clear delineation of customer account ownership, and the design of new incentive structures that reward cross-selling. Pulling the right enablement levers is just as critical as defining the initiatives themselves.
Cross-functional teams should also create detailed roadmaps and KPIs that can serve as a management accounting proxy to track the source of new revenues. Because revenue synergy planning often involves commercially sensitive information, clean teams are typically required to begin this work before close, but when done right, such planning can make revenue synergies as credible and “bankable” as cost synergies.
A leading software company’s $1 billion acquisition shows what disciplined revenue synergy execution looks like. In just three months—from announcement to close—it integrated the target, resolved organizational design issues, defined revenue synergies, and developed sales enablement and implementation plans. The company was poised to achieve significant year-over-year revenue growth from cross-selling, while also on track to deliver more than $100 million in cost synergies targeted for year one.
The company achieved this rapid progress by relentlessly focusing on joint commercial opportunities. It quickly developed product offerings and integrated development roadmaps, while tackling regular integration activities such as organization design, sales force design, and account planning. (See Exhibit 3.)
At close, the new go-to-market model launched with a joint sales kickoff and intensive training. To drive momentum, the company rolled out a year-one incentive program rewarding sales teams for selling the acquired company’s software to the expanded client base. The result: the organization was ready—and motivated—to cross-sell from day 1.
Track Performance Throughout Integration, and Be Clear About How
In PMI, the old adage holds true: if you don’t measure it, you can’t manage it. One of the most common—and costly—oversights is failing to systematically track synergies. Without a disciplined tracking process, leaders lose visibility into progress, targets become less ambitious, and critical interdependencies go unmanaged.
When companies see they are meeting their targets, it confirms that the merger is delivering as intended. Leaders can then fine-tune execution or pivot with confidence, while shared success boosts motivation across teams. Tracking also enables clear, objective communication of progress to investors—a practice that BCG research shows can translate directly into superior market performance. (See “The Value of Keeping Investors Informed.”)
The Value of Keeping Investors Informed
The integration plan provides the foundation for tracking synergy delivery. The IMO works with integration teams to create detailed roadmaps and milestones for each project, define the timing of synergies, map interdependencies and risks, and set KPIs to ensure steady progress. Together, the two groups also stress-test the plan’s rigor. Tracking revenue synergies requires monitoring not only the revenues generated but also the underlying initiatives and component actions driving those results.
A complete picture of synergy realization also requires careful tracking of integration costs—the expenses and one-time capital outlays needed to execute the initiatives. Achieving $1 of synergy may require spending up to $1.50 upfront, but while the costs occur only once, the synergy benefits recur year after year. Still, these costs can quickly erode short-term gains and drain cash flow, making it essential to ensure that each initiative delivers a positive return on investment. Costs can be tracked project by project within the integration plan.
Knowing what to track is only part of the solution. Acquirers must also be clear about how synergies will be tracked: the measurement principles, calculation methodology, governance for approvals, and process cycle. Key questions include: Are targets measured in real or nominal terms? Who provides sign-off that an initiative has been implemented and has delivered the claimed $10 million in savings? How often should the impact of each initiative be validated? And how does the tracking cycle fit into existing regular financial reporting processes?
One of the most critical synergy measurement principles relates to the definition of the baseline against which financial and FTE impacts are measured. Establishing a credible baseline is the foundation of effective synergy tracking. The methodology should be explicit—for example, using the prior year’s actuals and converting multiple currencies into the reporting currency at year-end spot rates. Building this baseline is complex, as companies often report at different levels of detail, follow varying accounting practices, and rely on multiple data systems.
Today, AI tools can accelerate the process by aggregating data from disparate sources and harmonizing differences more systematically. This results in a stronger foundation for synergy tracking and frees up management to focus on planning initiatives rather than validating data.
Once integration projects are finalized (before or at closing), they should be locked to create a single version of the truth against which progress is tracked. All plans and initiatives should then be entered into an implementation tracking system, ensuring a central repository of information. For example, KEY Impact Management by BCG X is a cloud-based tool that enables decentralized management of initiatives while giving the IMO a holistic, single-source-of-truth view with which to surface critical risks early. By linking milestones with value tracking, KEY provides leading indicators of whether delivery is on course. This allows teams to respond quickly to missed milestones, emerging risks, or performance shortfalls—and to make necessary interventions before issues escalate. Leaders can also see the potential impact of delays and proactively intervene to protect value and critical interdependencies.
All synergies and integration costs should be tracked monthly for the first two to three years to allow for swift course correction if projects veer off track; quarterly tracking is sufficient thereafter. Monitoring should continue until the final dollar of synergies is captured. Both synergies and integration costs should be tracked against the plan at the project level, using distinct metrics to measure realized value, headcount changes, and one-time expenses. A formal reconciliation process between project-level reporting and the finance view will then ensure accuracy and consistency.
The merger of two major US retailers demonstrates the powerful impact of disciplined tracking on achieving—or even surpassing—synergy targets. During due diligence, the companies estimated $300 million to $500 million in cost savings. The combined entity ultimately achieved $740 million. This outperformance was driven by a rigorous execution plan, anchored by detailed roadmaps for more than 100 synergy-related initiatives.
Preclose clean teams also played a critical role. By analyzing key metrics such as cost of goods sold, they enabled preliminary planning at the category and vendor level. As a result, immediately after closing, the company was positioned to pursue ambitious stretch targets across all major areas: corporate overhead, cost of goods sold, procurement, and even sales and marketing.
What ultimately distinguishes successful integrations is not only the right strategy and value thesis but also the steady application of practical disciplines. The essentials covered here are not flashy, but they work. Each one gives leaders a tangible way to maintain momentum, sharpen focus, and avoid the drift that undermines so many deals. Together, they form a playbook that makes the difference between synergies that remain on paper and those that show up in results. Organizations willing to commit to these practices will ensure that mergers realize their potential as platforms for growth and long-term value creation.
