The deal is signed, the champagne is gone- and the real work begins. For CFOs, having a defined M&A integration 100-day plan determines whether value is realized or written off.
Post-acquisition chaos is common: mismatched systems, duplicate vendors, inconsistent reporting, and cultural friction can quickly erode expected synergies. Harvard Business Review reports that 70–90% of acquisitions fail to meet synergy expectations, most due to poor integration discipline rather than flawed deal logic.
According to PwC’s 2025 Deals Outlook, only 38% of CFOs say they have a defined 100-day integration plan ready at close leaving most firms vulnerable to delays, confusion, and value leakage.
“The first hundred days decide whether a deal creates value or writes off goodwill,” says Brian, CFO Worx CEO.“Finance has to lead with control, visibility, and communication from day one.”
Immediately after close, clarity is king. Finance teams must establish control over cash, reporting, and access rights before integration expands.
Key actions:
Research from EY shows that companies integrating finance functions within the first 30 days retain 28% more expected synergy value than those that delay alignment for a quarter or longer.
Once controls are established, CFOs must bring financial clarity. Inconsistent definitions of revenue, cost centers, or project margins can distort performance tracking.
Priorities include:
“Numbers drive trust,” Brian notes.“When both sides speak the same financial language, you stop debating data and start managing outcomes.”
With data unified and teams aligned, CFOs can pivot from stabilization to optimization.
Focus shifts from firefighting to value creation.
Critical steps:
McKinsey’s 2025 M&A integration study found that companies with clear 100-day governance frameworks captured 60% of targeted synergies within the first year, compared to 30% for those without.
Even experienced CFOs stumble on integration pitfalls:
“Momentum matters,” Brian emphasizes.“If you lose the first 100 days, you spend the next year playing catch-up.”
At CFO Worx, we help companies bridge the gap between transaction and transformation.
Our M&A and CFO services focus on the first 100 days- establishing control, visibility, and confidence so financial operations scale with the new organization.
“Integration isn’t about merging spreadsheets,” says Brian.“It’s about merging trust. The faster you deliver transparency, the faster value compounds.”
Content Disclaimer: The information shared in CFO Worx Insights is for general informational purposes only and should not be considered professional, legal, accounting, or tax advice. Each company’s situation is unique, and readers should consult qualified advisors before making business or financial decisions.

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