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.”
Day 1 to 30- Control the Foundation
Immediately after close, clarity is king. Finance teams must establish control over cash, reporting, and access rights before integration expands.
Key actions:
- Communicate early. Internally align teams on who owns what: accounting, FP&A, and integration governance.
- Lock down bank accounts and cash management. Consolidate signatories, update permissions, and ensure treasury visibility across legacy entities.
- Standardize reporting cadence. Align the acquired company’s chart of accounts and reporting timeline with the parent’s cycle.
- Stabilize payroll and vendor payments. Avoid early disruptions by confirming data accuracy, open invoices, and pending obligations.
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.
Day 31 to 60- Align the Numbers and the Narrative
Once controls are established, CFOs must bring financial clarity. Inconsistent definitions of revenue, cost centers, or project margins can distort performance tracking.
Priorities include:
- Unifying accounting policies. Ensure revenue recognition, capitalization, and depreciation methods are consistent.
- Building a consolidated cash-flow forecast. Integrate assumptions and model combined liquidity risk.
- Re-forecasting EBITDA and synergies. Reset baselines to reflect integration timing and costs.
- Cultural alignment. Finance should host cross-team sessions to explain processes and KPIs. Transparency reduces resistance.
“Numbers drive trust,” Brian notes.
“When both sides speak the same financial language, you stop debating data and start managing outcomes.”
Day 61 to 100- Drive Synergy and Governance
With data unified and teams aligned, CFOs can pivot from stabilization to optimization.
Focus shifts from firefighting to value creation.
Critical steps:
- Communicate progress. Frequent updates keep investors and leadership confident that momentum is sustained.
- Integrate ERP and reporting tools. Consolidate to a single platform or ensure seamless data flow between systems.
- Measure synergy realization. Track targets- procurement savings, headcount efficiency, margin improvement- monthly.
- Formalize governance. Establish an integration steering committee with finance at the center.
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.
Common Traps to Avoid
Even experienced CFOs stumble on integration pitfalls:
- Waiting for “perfect” systems. Integration progress beats integration perfection.
- Underestimating data complexity. Legacy systems rarely align neatly- budget for data mapping early.
- Overlooking change management. Talent loss and burnout often occur when integration is rushed.
- Ignoring working-capital strain. Combined payables and receivables cycles can create liquidity surprises.
“Momentum matters,” Brian emphasizes.
“If you lose the first 100 days, you spend the next year playing catch-up.”
The CFO Worx Perspective
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.”
Just closed a deal or preparing for one?
CFO Worx helps mid-market firms navigate post-acquisition finance with disciplined 100-day integration plans that protect synergy, control, and cash flow.
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.