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By Joe Aberger
Speed wins in M&A. The 100-Day Post-Merger Integration framework compresses the critical work of combining two companies into a disciplined, time-bound plan. It starts 60 days before close and drives to business-as-usual by Day 100.
Phase 1: Pre-Close Planning (Days -60 to 0)
This is where integrations are won or lost. Teams define the end state, align executives on success metrics, and launch the Integration Management Office. Workstreams are chartered. Governance is built. Day 1 readiness is achieved.
Phase 2: Day 1 / Week 1 Execution (Days 1–7)
The first seven days set the tone for everything that follows. Leadership announces the new structure. Employees get clear answers. Customers hear a consistent message about service continuity. Vendors and partners receive formal notifications. A comprehensive FAQ keeps uncertainty from filling the vacuum.
Phase 3: To 100 Days — Integration Complete (Days 8–100)
This is where plans become results. IT systems migrate. HR policies align. Finance consolidates. Synergy tracking goes live against pre-close targets. Sales teams protect customer relationships through the transition. Cultural integration runs in parallel. By Day 100, two companies have become one.
The Bottom Line
One hundred days. Three phases. One unified, high-performing organization. That's the 100-Day Advisors' approach to post-merger integration.