On the day a deal closes, the price stops mattering and execution starts. Employees want to know whether their jobs are safe, customers wonder whether service will change and competitors call both. Every week without clear answers costs talent, revenue and credibility.
A plan on one page
A good hundred-day plan is organised around a handful of workstreams, each with an owner and clear milestones at day one, day thirty and day one hundred. It is prepared before closing, so the first day is about announcements, not about planning.
Day one: certainty
Announce the leadership team and the first two levels of the organisation, tell every customer who their contact is and explain what will not change. Uncertainty is more damaging than bad news.
Day thirty: quick wins
Start the synergies that are large, fast and low-risk, such as procurement and overlapping external spending, and show the first results. Early wins pay for the integration and convince both organisations that the deal works.
Day one hundred: one company
By day one hundred the combined company should report one set of numbers, run one management rhythm and have a synergy tracker that finance signs off. The remaining integration, such as systems and footprint, now runs as a programme with its own timetable.
The hundred-day plan is where the deal thesis meets reality. Companies that prepare it before closing, communicate relentlessly and measure weekly keep the value they paid for; those that improvise give it to their competitors.

