Why So Many Earnouts Don't Pay Out in Full, And How to Protect Yourself

Industry surveys and practitioner experience consistently suggest that somewhere between 30 and 50 percent of earnouts don't pay out in full. No single rigorous study captures the Australian SME market specifically, but the pattern is consistent across deal advisory practitioners and reported international M&A data: earnouts underperform at a rate that most sellers don't anticipate when they sign. Some pay nothing. Some pay a fraction. A meaningful proportion become the subject of disputes that drag on for years, and eventually settle for less than the seller was owed, because the cost and stress of pursuing the full amount wasn't worth it.

If you've been offered a deal with a significant earnout component, that reality should change how you read the term sheet in front of you. The headline number isn't your number. The earnout isn't a gift tied up with a bow. It's a contingent liability that the buyer holds most of the cards on.

This article isn't about what earnouts are or how they're structured, that's covered in detail elsewhere. This is about why they fail in practice, what the failure modes look like, and specifically what you need to do before signing to protect the amount you've been promised.

Why the Failure Rate Is So High

The structural problem with earnouts is this: the seller sets the target in negotiation, when they have leverage. The buyer controls the measurement environment post-settlement, when the seller has almost none. That asymmetry is baked into every earnout from the moment you agree to one.

A sophisticated buyer knows this. When they offer an earnout, they're not being generous. They're shifting risk back to the seller while maintaining control of the outcome. The earnout is a negotiating tool dressed up as consideration. It allows the buyer to offer a higher headline number while reducing the amount they're confident they'll actually pay. The gap between what's written in the heads of agreement and what ends up in your bank account is, in many cases, entirely predictable from how the earnout was structured.

Understanding the specific failure modes is the starting point for protecting yourself. There are five of them, and most earnout disputes trace back to one or more of these patterns.

Failure Mode 1: Metric Manipulation by the Buyer

Once you settle, the buyer controls the P&L of your former business. They control how revenue is recognised, how costs are allocated, and what gets charged to which entity. If your earnout is tied to EBITDA, which it often is,those levers matter enormously.

The most common version of this looks like overhead reallocation. The buyer is a larger business with head office costs: group insurance, shared IT systems, centralised finance functions, executive salaries. Post-acquisition, they allocate a portion of these costs down to the acquired entity. That allocation is often a round number and rarely reflects actual usage. But it appears on the P&L of your former business, and it drags EBITDA below the threshold required to trigger your earnout payment.

A $200,000 head office allocation charge on a business with a $500,000 EBITDA earnout threshold means you need to generate $700,000 in EBITDA to receive any earnout, even though the actual operating performance of the business would have cleared the threshold easily without it. The buyer hasn't done anything illegal. They've simply exercised control over accounting that was always within their rights, because you didn't restrict it before signing.

The same problem arises with intercompany pricing. If the buyer starts routing supplier contracts through the parent entity and on-charging them to your former business at a margin, costs rise and EBITDA falls. If they shift revenue recognition policy so that certain contracts are treated as group revenue rather than entity revenue, the top line shrinks.

Failure Mode 2: Integration Destroys the Measured Entity

This failure mode is structurally different from metric manipulation, but the outcome is often the same: the earnout becomes impossible to measure.

Buyers acquire businesses because they want to integrate them. They want to consolidate customers, merge teams, rationalise systems, and create the synergies that justified the purchase price. That integration is commercially rational, from the buyer's perspective. From yours, it can mean that the earnout metric you agreed on becomes unmeasurable before the earnout period ends.

Consider a scenario: you sell a software business with 200 customers. The buyer has 800 customers of their own. Twelve months into the earnout period, the buyer migrates all 1,000 customers to a single platform, consolidates the two sales teams, and begins issuing unified invoices from the group entity. Your former business no longer exists as a separate operating entity. The customers it had are now group customers. The revenue it generated is now group revenue.

How do you calculate the EBITDA of an entity that has been fully absorbed into a larger business? You can't, at least not in any way the buyer will agree to. Your earnout, which was tied to the standalone performance of the acquired business, is now tied to a measurement that neither party can verify. Disputes arise. Legal costs mount. The earnout either gets written off or settled for a fraction of its value.

Failure Mode 3, Key Person Departs (and the Earnout Goes with Them)

Many earnouts are implicitly or explicitly contingent on the seller remaining in the business. This is often framed as a transition service obligation, you agree to stay for 12 to 24 months to ensure continuity,but in practice, it creates a different kind of risk entirely.

The risk is this: you stay, the business performs, and the earnout target is within reach. Then something goes wrong in the relationship with the new owner. A disagreement over strategy. A decision you were overruled on. A new management structure that makes your role marginal. The situation becomes untenable, but you can't leave, because your earnout is tied to your continued employment.

In the worst cases, the buyer uses this dynamic deliberately. They don't need to push you to quit. They just need to make your working conditions uncomfortable enough that you eventually do. If your earnout agreement specifies that it is forfeited on voluntary resignation, every day you stay in an intolerable situation is a day you're spending to protect the earnout rather than working because you want to be there.

The legal concept of constructive dismissal applies here, where an employer makes working conditions so unreasonable that resignation is the only rational response. But constructive dismissal claims in Australia are expensive to pursue and uncertain in outcome. The time and legal cost of establishing constructive dismissal often exceeds the practical value of doing so, particularly on an earnout amount below $500,000.

Failure Mode 4: Market Conditions Outside Your Control

Earnout targets are set at the time of negotiation, based on the economic conditions and business trajectory that existed at that moment. If those conditions change materially during the earnout period, the target that was achievable when you agreed to it may become structurally impossible.

This is particularly acute for revenue-based earnouts in cyclical industries. A distribution business with a target of 15% revenue growth, agreed during a period of strong consumer demand, may find that growth turns negative in a correction. A professional services firm with a client retention target may lose clients to budget cuts in a downturn, not because of anything the seller did wrong, but because the market contracted.

The earnout contract doesn't care. The target is the target. If you don't hit it, you don't receive the payment, regardless of whether the miss was within your control. The buyer doesn't lose money; their acquisition price adjusts down automatically. The seller loses the earnout regardless of how well they actually managed the business.

Australian business owners selling into 2024 and 2025 have seen this play out in real time. Revenue targets agreed during the 2021–22 growth period look very different in a higher-rate environment with compressed consumer spending. The businesses performing well on a relative basis, growing or holding revenue while competitors contract,are nonetheless failing their absolute earnout targets.

Failure Mode 5: The Dispute Costs More Than the Earnout

This is perhaps the most insidious failure mode, because it operates at the level of rational economics rather than bad faith by the buyer. The buyer doesn't need to be dishonest for this failure mode to play out. They just need to know that litigation is expensive.

When an earnout dispute arises, the seller's options are limited. They can attempt to negotiate informally, which the buyer has little incentive to engage in unless they're genuinely concerned about legal exposure. They can engage lawyers to write strongly worded letters,which consume fees and rarely produce earnout payments. Or they can litigate.

Litigation over earnout disputes in Australian courts is a slow, expensive process. Commercial litigation involving detailed accounting disputes, which earnout cases almost always become,requires expert witnesses, extensive document discovery, and considerable legal fees at every stage. A matter disputing a $400,000 earnout shortfall can easily generate $150,000 to $250,000 in legal costs before you see the inside of a courtroom, and the outcome remains uncertain throughout. Buyers understand this arithmetic. Some rely on it.

The result is that earnout disputes often settle for less than the seller was owed. Not because the seller was wrong, but because the economic calculus of pursuing the full amount didn't support the effort. The buyer, with substantially more legal resources and institutional experience in dispute management, is structurally advantaged in this dynamic.

What Percentage of Your Sale Price Should an Earnout Represent?

There's no universally right answer, but a widely cited practitioner rule of thumb is that earnouts representing more than 20% of total deal consideration expose sellers to disproportionate risk. Above that threshold, the deferred component is large enough that losing it materially changes your financial outcome, and you've given up too much certain value in exchange for a contingent promise. This threshold isn't a hard rule, but it serves as a useful prompt: the larger the earnout proportion, the more critical it is that each failure mode below has an explicit contractual protection.

At under 20%, an earnout can be a rational way to bridge a valuation gap. If the buyer believes your forward earnings are $800,000 and you believe they're $1.2 million, a modest earnout that pays out if the higher number is achieved is reasonable deal-making. You receive most of your value upfront; the earnout captures the upside if you're proven right.

Above 20%, the earnout begins to resemble a seller-financed acquisition, where the buyer is effectively funding a portion of the purchase price with your own future earnings. At 30% or 40% earnout, you need to ask yourself whether the deal you've agreed to is actually a deal, or whether you've agreed to receive most of your sale consideration contingent on outcomes you no longer control.

Earnout as % of total consideration	Risk profile	Comment
Under 10%	Low	Manageable upside. Losing it doesn't change the deal fundamentals.
10–20%	Moderate	Acceptable with tight protections in place. Negotiate carefully.
20–35%	High	Significant exposure. All five failure modes require explicit contractual protection.
Above 35%	Very high	Reconsider the deal structure. You may be better served by a lower headline with more upfront certainty.

How to Evaluate Whether an Earnout Offer Is Actually Worth Accepting

Before accepting a deal with a material earnout component, work through four questions with independent support, not with your broker, who has a financial interest in the deal closing.

First: discount the earnout realistically. If the base failure rate is 30–50%, the statistical expected value of a $1 million earnout is somewhere between $500,000 and $700,000. That is, 50–70 cents in the dollar, before accounting for the specific risk profile of your deal and buyer. Is the total consideration still attractive when you read the earnout at that discounted value rather than face value?

Second: assess the buyer's track record. Have they made acquisitions with earnout structures before? Did those earnouts pay out? This information is knowable. It's the kind of diligence that should be done on the buyer before you agree to a structure that puts you at their mercy for two years.

Third: model the scenario where integration happens early. What does the deal look like if the buyer integrates your business within the first six months? Is your earnout protected by carve-out provisions that make it measurable regardless of integration? If not, what is the effective value of the deferred consideration in that scenario?

Fourth: consider the opportunity cost. The earnout period is typically 12 to 36 months during which you are often contractually obligated to remain employed. What is the cost of your time during that period? What alternatives are you foregoing? If the earnout represents a modest premium over an alternative deal with higher upfront certainty, the opportunity cost may not be worth it.

Earnouts are not inherently bad deal structures. They exist because they solve a real problem, the gap between what a buyer is prepared to pay with certainty and what a seller believes the business can achieve. But they are high-risk instruments for the party who doesn't control the outcome. Understanding what a fair value for your business actually looks like is the starting point for knowing whether an earnout-heavy offer reflects genuine consideration or a clever reallocation of risk.

The five failure modes in this article don't require a dishonest buyer. They require only a sophisticated one, one who knows that the contractual protections you didn't ask for are the protections they'll never have to honour. Every one of these failure modes is preventable. None of them are automatically prevented by the fact that you have a signed earnout agreement.

Get the structure right before you sign, or don't sign at all.