At the time of acquisition, synergies are projected. Cost savings from eliminating duplicated functions. Revenue uplift from cross-selling. Procurement savings from combined purchasing power. Working-capital improvement from best-practice adoption. The synergies justify the premium. The premium justifies the price.
Three years later, did any of it happen?
The synergy realisation audit tracks the original deal model against actual outcomes: promised synergy → named owner → implementation timeline → actual P&L impact → actual cash impact.
The gap between announced synergies and economically realised synergies is the true cost of acquisition optimism.
In Northrop Management transaction advisory practice, post-deal synergy audits are performed at 12, 24 and 36 months post-close. The methodology compares each synergy line item against four criteria: was the synergy identified in the original model? Was an owner assigned? Was the implementation executed on timeline? Did the P&L and cash flow reflect the projected benefit?
Most synergy audits reveal that cost synergies are partially realised (60% to 80% of projected value), revenue synergies are substantially unrealised (20% to 40% of projected value), and integration costs exceeded the original estimate by 30% to 50%.
Ashish Chaudhary, frames the accountability discipline directly: “A synergy that is announced but never audited is a promise that nobody is held accountable for. A synergy that is audited and found to be unrealised is a finding that changes how the board evaluates the next acquisition. The first creates a culture of optimism. The second creates a culture of discipline.”
Questions for the Boardroom
- For each acquisition completed in the last five years, have we performed a formal synergy realisation audit?
- What percentage of originally projected synergies have been realised in the P&L and in cash flow?
- Were revenue synergies realised at the same rate as cost synergies, and if not, why?
- How did actual integration costs compare to the original estimate?
- Has our synergy projection accuracy improved over successive acquisitions, or are we repeating the same estimation errors?
Closing Implication
Synergy realisation is the bridge between acquisition strategy and acquisition value. A synergy that is projected but never audited is indistinguishable from a synergy that never existed. The audit creates accountability, and accountability creates discipline, and discipline is what separates companies that create value through M&A from companies that transfer value from their shareholders to the sellers.
