Modeling Synergies Without Lying
The Hook
Synergies are the magic word that justifies overpaying for an acquisition. Most of them never show up. The person who can tell a real synergy from a hopeful one, and put an honest number on it, is the person who keeps a company from torching a fortune on a deal that looked brilliant on a slide.
Plain English
A synergy is the extra value created by combining two companies that neither could produce alone, often summarized as the idea that one plus one can equal three. There are two kinds. Cost synergies are savings from cutting duplicate costs after a merger: one headquarters instead of two, one accounting team, better prices from buying in larger volume. These are relatively reliable because you control them. Revenue synergies are new sales the combined company hopes to win: selling each other's products to each other's customers, entering new markets together. These are seductive and mostly fantasy, because they depend on customers behaving the way you hope. The honest modeler does three things. First, separate cost synergies from revenue synergies and trust the cost ones far more. Second, subtract the cost to achieve the synergies (integration is not free). Third, push the timing out, because synergies almost always arrive later and smaller than the pitch promised.
The Math
An honest synergy estimate is never just a gross savings number. It nets out what it costs to capture the synergy and accounts for the year-by-year ramp, because savings that take three years to fully arrive are worth far less than savings claimed on day one. The discipline is to model net synergies, not headline synergies.
- Net annual synergy = (cost synergies + revenue synergies) - costs to achieve them
- Be honest about timing: ramp synergies in over several years rather than booking the full amount in year one
- Sanity check: weight revenue synergies heavily downward, because they are far less certain than cost synergies
A deal pitch claims 30,000,000 dollars of annual synergies. Break it down honestly. Cost synergies are 20,000,000 (closing a duplicate office, merging back-office teams, better supplier pricing). Revenue synergies are claimed at 10,000,000 (cross-selling). Now net it out. Achieving the cost savings requires 12,000,000 dollars of one-time integration spending (severance, systems, moving costs), and ongoing costs of 2,000,000 a year. So net annual synergy in a steady year = (20,000,000 + 10,000,000) - 2,000,000 ongoing = 28,000,000, but only after spending 12,000,000 upfront. The headline was 30,000,000; the honest steady-state figure is 28,000,000 with a real bill to get there. And that still assumes the revenue synergies are fully real, which is the next problem.
Take the 10,000,000 dollars of claimed revenue synergy from cross-selling. History across acquisitions shows revenue synergies routinely come in at a fraction of the pitch, because customers do not automatically buy the new product, sales teams resist selling unfamiliar lines, and competitors fight back. A disciplined modeler applies a heavy haircut: assume only 30 percent actually arrives, so 10,000,000 x 0.30 = 3,000,000 dollars. Redo the net figure with cost synergies fully counted but revenue synergies haircut: (20,000,000 + 3,000,000) - 2,000,000 ongoing = 21,000,000 dollars in a steady year. That is the number you should defend, not the 30,000,000 on the slide. Telling the difference is what stops a company from overpaying.
Even real synergies do not arrive on day one. Say steady-state net synergies are 21,000,000 dollars a year, but they ramp: roughly 25 percent in year one (5,250,000), 60 percent in year two (12,600,000), and 100 percent by year three (21,000,000), while the 12,000,000 integration cost is spent mostly in year one. So year one actually looks like 5,250,000 of savings against 12,000,000 of cost, a net outflow of about 6,750,000 dollars before the deal starts paying off. A pitch that books the full 21,000,000 from day one overstates near-term value badly. Modeling the ramp honestly is the difference between a forecast people can trust and one that quietly sets the team up to miss every target.
The Lingo
- Synergy
- Extra value from combining two companies that neither could create alone, the idea that one plus one can exceed two.
- Cost synergy
- Savings from cutting duplicate costs after a merger, like one headquarters or one finance team. Relatively reliable.
- Revenue synergy
- New sales the combined company hopes to win, such as cross-selling. Seductive but far less certain.
- Cost to achieve
- The one-time and ongoing spending required to actually capture a synergy, such as severance and systems integration.
- Net synergy
- Total synergies minus the cost to achieve them. The number that actually matters.
- Haircut
- A deliberate downward adjustment to an estimate to reflect uncertainty, applied heavily to revenue synergies.
- Ramp
- The schedule by which synergies arrive over time, usually building up over several years rather than appearing at once.
Practice
In the Room
The Trap
Counting gross synergies, leaning on revenue synergies, and booking the full amount on day one. That is the trifecta that justifies overpaying for a deal that then disappoints. The fix is disciplined: net out the cost to achieve, haircut revenue synergies heavily because they usually do not materialize, and model a multi-year ramp instead of an instant switch. If a deal only works on aggressive revenue synergies booked immediately, the deal probably does not work.
Quick Check
Q1.Why are cost synergies generally more reliable than revenue synergies?
Q2.What does net synergy account for that a headline synergy number ignores?
Q3.Cost synergies are 20,000,000 dollars, revenue synergies are 10,000,000 dollars, and ongoing costs to capture them are 2,000,000 dollars per year. What is the steady-state net annual synergy?
Q4.A modeler haircuts 10,000,000 dollars of claimed revenue synergies to reflect that only 30 percent is likely to arrive. What revenue synergy do they book?
Q5.Why should synergies be modeled with a ramp instead of booked fully in year one?
Practice Out Loud
A deal sponsor is defending an acquisition price using 30,000,000 dollars of synergies, most of it cross-selling revenue. In 90 seconds, walk through how you would pressure-test that number and explain what figure you would actually put in the model. The AI will play the sponsor who pushes back: you are being too conservative, the strategic upside is huge.
Try it in real life
This week, pick one company you follow and find one real world example of modeling synergies without lying. Write down what you noticed in two sentences.
Wrap up this lesson
Submitting the Quick Check counts. Or mark it here when you feel ready.