Every roll-up begins with a thesis about fragmentation: many small businesses, one platform, arbitrage between the multiple paid for the pieces and the multiple earned by the whole. The thesis is usually sound. What fails is the assumption underneath it, that acquired companies naturally become one company. They do not. Left alone, each acquisition keeps its own systems, its own reporting and its own way of working, and the platform is a thesis with a shared logo.
Why the first hundred days decide it
Integration is easiest immediately after close, when change is expected and the acquired team is looking for direction. Every month of delay hardens the status quo. The first hundred days note covers the sequence: one reporting basis, one cash view, shared services for finance and people operations, and a cadence that connects the acquired business to the platform's operating review. Miss that window and the work is the same, but the resistance is not.
This is why Opsist treats integration as an operating discipline rather than a transaction workstream. The multiple arbitrage in the thesis is only collected when the businesses actually share one operating system. The spreadsheet assumes the integration. The first hundred days are where the assumption is made true.