100-Day Consolidated Post-Merger Integration Plan

This free Excel workbook is a completed, cross-functional 100-day post-merger integration plan that spans these workstreams: HR, IT, Finance, Legal, Sales, Communications, and IMO. 

Each sheet follows the same disciplined structure. Every task has a unique ID, a category, a milestone it belongs to, a phase (Pre-Close, Day 1 Readiness, Day 1/Week 1, or To Day 100), a named owner, a timing anchor tied to the close date, start and finish dates, a status, a completion percentage, a critical path flag, an issues/blockers field, a risk level, and cross-workstream dependencies. 

The synergy columns — hidden by default — capture synergy description, planned value, cost to achieve, realized value, and actual cost, giving Finance a live reconciliation tool baked directly into the plan.

At the date of this plan, 30 days post-close, the pre-close and Day 1 tasks are complete. Other tasks through Day 100 are in various states — on track, delayed, or not started — giving the integration team a real-time picture of where the work stands at T+30.

The task notes makes this workbook is especially valuable. Every row includes substantive guidance — not just what to do, but why it matters, what goes wrong when it's skipped, and what the downstream consequences are. Notes on payroll tax registration lead times, WARN Act triggers, SIEM coverage requirements, CRM field mapping risks, and synergy owner accountability are written for practitioners, not administrators.

Taken together, the seven sheets function as a single operating system for the integration — one document that lets the IMO, the Steering Committee, and every workstream lead see the full picture, track dependencies, own their tasks, and measure progress against the deal thesis in real time.