For a decade, you could buy growth. Now you have to build it.

There is a specific kind of deal that used to work almost regardless of how well it was run. Cheap debt, rising valuation multiples and a following economic wind meant a competent acquirer could pay a full price, hold for five years, and hand investors a healthy return even if the acquired business did nothing heroic. The market did the heavy lifting. That arithmetic has quietly broken.

In its Global Private Equity Report 2026, Bain put a number on the change. A typical deal in the golden decade of the 2010s needed only around 5% average annual EBITDA growth to generate a benchmark 2.5x return over a five-year hold. Today, the same return requires roughly 10% to 12%. Bain's shorthand is blunt: "12 is the new 5". With leverage lower, borrowing costs sitting at 8% to 9%, and entry multiples still high, financial engineering no longer closes the gap. The growth has to be real, and it has to be operational.

This is not only a private-equity problem. Any company that uses acquisition as a growth lever now faces the same maths. If you are a growth or mid-market business eyeing a competitor, a founder considering your first bolt-on, or a leadership team under pressure from an investor to "consolidate the market", the required rate of operational improvement has roughly doubled. The deal that would have cleared the bar in 2016 will not clear it now.

The market is busy, which makes the mistake easy

The temptation to keep transacting is strong. Bain reports that 2025 buyout value surged to about $904bn, a 44% jump on the prior year and the second highest total on record, even though the number of deals fell by 6%. In other words, fewer but larger deals, and a lot of capital looking for a home. Around 80% of M&A executives say they expect to sustain or increase activity through 2026, despite a choppy macro backdrop of tariff disruption, higher oil prices and tighter credit.

A busy market is exactly where the old habit becomes dangerous. When everyone around you is doing deals, the pressure is to move quickly and worry about value creation later. That was survivable when the maths was forgiving. It is not survivable now. The single most expensive error available to an acquisitive leader in 2026 is to underwrite a deal on the economics of the last cycle.

Why most acquisitions still disappoint

The failure mode has not changed. What has vanished is the slack that used to hide it. Study after study puts the share of deals that fail to capture their planned synergies at well above half. When money was cheap, a deal could badly miss its synergy case and still clear the return bar, because the multiple and the leverage carried it. Now there is nowhere to hide a miss.

Three patterns explain most of the disappointment, and all three are avoidable.

The value-creation plan is written after completion, not before. In many deals, integration is handed to "whoever has capacity" once the ink is dry. By then the momentum, and often the goodwill, has gone. The plan to actually deliver the growth should exist, and have an owner, before you sign.

Synergies are totalled on a slide but never costed, timed or sequenced. A number in a deal model is a hypothesis. It becomes a commitment only when someone has said which synergy lands on day one, which by day 100, and which by the end of year one, and what each will cost to achieve. Most models never make that translation.

The core business stalls while attention is on the deal. Acquisitions fail as often from distraction in the existing business as from problems in the target. The management time an acquisition consumes is almost always underestimated, and the growth you already had is quietly the first casualty.

The evidence favours the disciplined, repeat acquirer

There is a well-documented alternative to the occasional big swing. McKinsey's long-running research on what it calls programmatic M&A, drawn from its Global 2,000 study across 2013 to 2023, finds that companies which acquire steadily and systematically, through a regular stream of small and mid-sized deals, outperform their peers. Programmatic acquirers delivered around two percentage points higher excess shareholder returns a year, and had roughly a 65% chance of beating their peer group. Companies relying on large, selective deals faced closer to even odds.

The lesson is not "do more deals". It is that the winners treat acquisition as a repeatable capability with a standard playbook, not a one-off event improvised each time. They get better at integration precisely because they do it often and deliberately.

The Value Test: six questions to answer before you sign

You do not need a corporate development team to apply this discipline. You need to refuse to sign until you can answer six questions cleanly. Score each from 1 (cannot answer) to 5 (answered with evidence). Any question scoring 3 or below is where the deal is most likely to disappoint.

  1. Growth. Where, specifically, will the growth come from? Name the two or three concrete sources (new customers, cross-sell, pricing, cost removal) and put a number on each. If the honest answer is "the market will grow" or "the multiple will re-rate on exit", you are underwriting the old maths.
  2. Stress test. Does the deal still work if growth comes in at 5% rather than 12%, and at today's cost of debt? Model the return on conservative assumptions. If it only works on heroic ones, the price is wrong, not the plan.
  3. Ownership. Is there a named person accountable for the value-creation plan before completion? Not a workstream, a person. Deals that appoint an integration owner after close are the ones that leak value in the first hundred days.
  4. Capacity. Can your existing business absorb this without stalling? Be specific about whose attention the deal will consume, and what in the core will get less of it. If the answer is "our best people, who are already fully committed", you have found a real risk.
  5. Synergy reality. Are the synergies costed, timed and sequenced across day one, day 100 and year one, or simply totalled? A dated, owned plan is a commitment. A total on a slide is a wish.
  6. Repeatability. Is this a one-off, or the first move in a repeatable system? Even if you only ever do one deal, building a proper playbook for it forces the discipline that the evidence rewards.

And one rule that sits above the six: decide your walk-away price before you fall in love with the target. The discipline to walk is what protects every other answer on the list.

What a weak answer is telling you

A low score is good news, because it is cheap to fix before completion and expensive to fix after.

If Growth scored low, stop and rebuild the thesis around two or three quantified, specific sources of value. If you cannot find them, you have your answer.

If the Stress test scored low, the issue is usually price. Rework the offer so the deal survives conservative growth, or step back.

If Ownership scored low, name the integration owner now, and give them the plan and the authority before you sign, not after.

If Capacity scored low, sequence the deal around your real bandwidth, or bring in outside capacity for the integration so the core does not stall.

If Synergy reality scored low, convert the model into a dated, costed, sequenced plan before completion. This one exercise removes more post-deal disappointment than any other.

If Repeatability scored low, write the playbook now. Even a first-time acquirer benefits from doing the deal as if there will be a second.

The shift, in one sentence

You can no longer buy growth and wait for the maths to work in your favour. You have to build the growth, deliberately, from the day the deal completes. The acquirers who understood the old cycle assumed the market would reward them. The ones who will win this cycle assume nothing, and plan the value in before they pay for it.

If you are weighing an acquisition, or midway through a buy-and-build programme, the most valuable hour you can spend this quarter is running your next deal through the six questions above before anyone signs anything.

How Allington Advisors helps

Our Growth & Expansion team works with founders and leadership teams to make acquisitions actually earn their growth. We pressure-test the deal thesis before completion, turn modelled synergies into a dated value-creation plan with a named owner, and, where the value sits in the running of the combined business, our Operations & Efficiency work makes the new organisation faster and cheaper to run. Where the question is whether to acquire at all, our Strategy Consulting team helps you weigh acquisition against the organic alternatives.

If you have a deal on the table, or a programme that is not delivering the growth it promised, we should talk. Book a pre-deal value review with Allington Advisors and we will help you find out, before you sign, whether the deal earns its growth or just hopes for it.