Earn-Out Clauses in M&A.

The seller sees a purchase price of EUR 12 million; the buyer does not want to go above EUR 9 million. Both sides are looking at the same historical numbers and still end up in different places, because the real dispute concerns the future: if growth remains stable, the higher price was plausible; if performance drops after closing, the buyer has paid too much. That gap is where the earn-out sits.

This article explains why earn-outs are used, which metrics and models appear in practice, where the main points of dispute lie and which mechanisms the parties use to balance the risk. An earn-out is never just a formula.

Why parties use earn-outs at all

An earn-out links part of the purchase price to the future performance of the business. The buyer pays a fixed amount at closing and another amount later if certain financial or operational targets are met. In law-and-economics terms, this is a bridge between diverging expectations.

From the buyer’s perspective, the mechanism reduces the risk of overpayment. From the seller’s perspective, it preserves the chance of realising the higher price after all if the seller’s planning proves correct. That sounds elegant. It is – but only if the measurement logic and the post-closing governance are clearly regulated.

Earn-outs are especially common in three situations: in growth businesses with uncertain planning, in owner-dependent targets whose development still depends on the seller’s transitional involvement, and in businesses whose value is driven heavily by individual projects, regulatory approvals or customer relationships. They also appear frequently where buyer and seller simply cannot agree on valuation.

In practice, earn-outs appear in roughly one quarter to one third of transactions, depending on deal size, market conditions and sector. In life sciences deals, earn-outs and milestone payments tend to play an even larger role.

An earn-out therefore does not automatically solve the valuation dispute. It often shifts that dispute into the future. That need not be a bad thing. But it does explain why these purchase price clauses are particularly prone to conflict.

Which metric fits the deal

The reference metric determines what the earn-out is measured against. Even more important is one point: the parties must not stop at the label. An earn-out based on EBITDA may mean something economically very different in two contracts, depending on whether integration costs, intra-group charges, one-off items, changes in provisions or amortisation resulting from purchase price allocation (PPA) are carved out.

So before cap, floor or term are discussed, the definition needs to be fixed. Which accounting standards apply? Which add-backs are permitted? How are transactions with group companies treated? And what happens if the reporting framework changes after closing? Only then does a metric become a robust purchase price logic. How closely these definitional questions are tied to the reference accounts is shown in the article on balance-sheet warranties; for the cut-off-date purchase price mechanics alongside it, see Locked Box vs. Closing Accounts.

Decision guide: Which metric fits when?

Metric	Tends to fit where …	Main issue
EBITDA	operating earning power before financing, taxes and depreciation/amortisation is the main focus	sensitive to overhead, add-backs, provisions and integration costs
EBITA	acquisition-related amortisation of intangibles should be excluded, while depreciation of tangible assets remains economically relevant	in German share deals, it is useful only if such amortisation actually appears in the chosen measurement basis
EBIT	the business is capital-intensive and tangible asset depreciation matters economically	accounting depreciation and actual investment needs do not always match
Gross profit	customer, product or project margins matter more than downstream overhead	direct costs, rebates, freight and intra-group services must be clearly delineated
Revenue / net revenue	growth, market share or customer retention is central	says little about profitability; discounts, returns, channel conflicts and revenue recognition must be defined
ARR / recurring revenue	SaaS or subscription value drivers are central	churn, upgrades, discounts, migrations and non-recurring components must be delineated
Qualitative milestones	value is driven by an objectively verifiable event, such as approval, release or key customer	partial achievement, delay, evidence and buyer efforts must be regulated

EBITDA

EBITDA (earnings before interest, taxes, depreciation and amortisation) is the most common reference metric. The reason is straightforward: the metric is meant to capture the operating earning power of the business without placing financing, taxes and depreciation policy at the centre. In service and software businesses in particular, that is often the natural starting point.

Its strength is also its weakness. EBITDA reacts sensitively to decisions controlled by the buyer after closing, for example intra-group management fees, the treatment of integration costs, capitalisation instead of immediate expensing or the creation of provisions. Example: the target generates operating EBITDA of EUR 3 million; after the acquisition, the buyer charges it EUR 400,000 in intra-group overhead. That may make commercial sense within the group. For the earn-out, it can make the difference between full payment and no payment at all.

Caution: Anyone choosing EBITDA almost always needs detailed accounting principles and a clear rule on intra-group charges. Otherwise, a familiar metric quickly turns into an open field for interpretation.

Although free cash flow, as a post-investment and post-tax metric, is often more relevant for business valuation, EBITDA remains the preferred earn-out metric: it is more clearly defined, more resistant to manipulation and still meaningful during growth phases in which free cash flow may be structurally negative.

EBITA

EBITA excludes amortisation of intangible assets, but leaves depreciation of tangible assets in the metric. The idea is simple: depreciation on tangible assets reflects real wear and tear and investment requirements; amortisation of intangible assets may, by contrast, be a pure accounting effect from earlier acquisitions that has little to do with the target’s current operating performance.

Compared with EBITDA, EBITA is therefore more precise where one wants to exclude only acquisition-driven intangible amortisation, while keeping the capital intensity of the business in view. A manufacturing company that steadily consumes machinery should keep that depreciation in the earn-out metric; under EBITDA, it would be stripped out.

In German SME practice, however, EBITA remains the exception. The first question is where the metric is measured. In a typical share deal based on the target’s HGB stand-alone financial statements, the buyer’s purchase price allocation does not show up there; the buyer books the acquired shares, while the target’s assets are not revalued in its own accounts. PPA amortisation is therefore more likely to appear at buyer-group, IFRS, pro forma or management-reporting level. At target level, it mainly becomes relevant if the target itself makes acquisitions during the earn-out period and recognises intangible assets, or if such assets already exist from earlier transactions.

An EBITA approach should therefore be used only where the selected measurement basis actually contains acquisition-related amortisation. Otherwise, the metric solves a problem that does not arise in the specific deal and makes the contractual definition unnecessarily heavier. In many German transactions, practice therefore works with EBIT, EBITDA or a contractually precise adjusted metric with specific add-backs.

EBIT

In capital-intensive businesses, the earn-out is often linked to EBIT. Unlike EBITDA, EBIT captures depreciation on tangible assets and therefore reflects more accurately that operating performance in such business models cannot be considered without machinery, equipment or infrastructure. That is relevant, for example, in manufacturing, logistics or certain technical services.

The practical idea is that the metric should not completely ignore the economic wear and tear of fixed assets. Pure EBITDA can make a capital-intensive business look too strong where recurring replacement and maintenance investment is required. EBIT at least brings accounting depreciation into the metric. Even so, the issue is not solved completely, because accounting depreciation and economically required maintenance capex do not necessarily match.

An example shows the difference. Two targets each generate EBITDA of EUR 5 million; one of them operates with an old, capital-intensive machine park and records depreciation of EUR 2 million. For that company, EBIT is often closer to economic reality as the reference metric.

Gross profit

A reference metric that is often sensible in practice, but surprisingly often underestimated, is gross profit. Put simply, this means revenue less directly attributable production costs or direct service costs. Overheads, group charges and many integration decisions do not normally affect it.

The advantage is obvious. The buyer can influence the earn-out less easily through downstream overhead decisions, because those decisions usually do not affect gross profit. Especially in owner-managed businesses and smaller to mid-sized transactions, this metric is therefore often seen as more workable than EBITDA. Sellers like it because it keeps the result closer to market performance and further away from the buyer’s group structure. Buyers are more likely to accept it where the value thesis is driven primarily by revenue quality, product-level margins or customer profitability.

The dispute over definitions does not disappear, however. It merely moves. Which costs count as direct costs? How are bonuses, rebates, returns, freight, intra-group procurement or intra-group service charges treated? Without precise delineation, an earn-out based on gross profit is not conflict-free either. It is simply contentious at a different point.

Revenue

Revenue-based earn-outs are easy to measure and, at first sight, less susceptible to accounting-policy interference. That makes them attractive especially where growth, market share or the monetisation of a customer base is the central issue, for example in SaaS models with high contribution margins or in early growth phases. The metric is quickly understood. That helps in negotiations.

For that reason, contracts often do not measure simply “revenue”, but net revenue, revenue from specific products, ARR, customer revenue or gross bookings less clearly defined deductions. That sounds technical, but it is often decisive: discounts, returns, credits, channel revenue, revenues with affiliates, contract migrations and changes to revenue-recognition policy can materially shift the result.

The drawback is just as obvious. Revenue says little about profitability. A buyer may fund growth at almost any price; a seller may argue that this very growth is what drives enterprise value. Both can be true. Revenue-based earn-outs therefore fit better where profitability is deliberately secondary or protected in some other way.

A practical middle ground is a revenue or ARR target combined with a profitability condition, for example a minimum gross margin or gross-profit corridor. Growth is then rewarded, but not at any price. From the seller’s perspective, it is crucial that the margin cannot be pushed below the threshold after closing through the buyer’s pricing decisions, product bundling, procurement requirements or group charges.

Qualitative milestones

Not every earn-out depends on a classic financial metric. Especially in regulated sectors, product development businesses or project-driven companies, the parties may agree qualitative milestones, for example a regulatory approval, technical completion of a software release, market entry into a specific country or the conclusion of a named key-customer contract. The logic is then less about accounting and more about the specific deal thesis.

This can work very well if the event is objectively verifiable. It becomes difficult where the milestone has been achieved only in part, with delay or in modified form. Without rules on partial achievement, responsibility and evidence, an all-or-nothing outcome quickly threatens. That is exactly where proportional or linear partial-payment models come in.

In milestone earn-outs, it is also important who can actually influence the milestone after closing. If the buyer controls product development, regulatory approval, budget or launch, the seller will often need buyer-efforts covenants, information rights and rules for cases in which integration, project prioritisation or a change of control effectively devalues the milestone.

Which earn-out models appear in practice

The reference metric answers the question what is being measured. The model answers the question how that measurement translates into money. Many conflicts do not arise over the metric itself, but over how the metric is turned into payment.

Linear formulas: base amount or factor

Many earn-outs do not follow a separate model category, but a linear curve. Below the floor, nothing is paid; above the floor, the payment increases proportionally until an agreed amount, target metric or cap is reached. Practice simply describes that curve from different starting points.

The first variant starts with the payout amount. The parties agree a base amount and a 100% payout metric: below EUR 2 million EBITDA, nothing is paid; at EUR 4 million EBITDA, the EUR 1 million base amount is fully earned; in between, the payout is proportional. At EUR 3 million EBITDA, the earn-out is therefore EUR 500,000. The implied slope in this example is EUR 0.50 earn-out for each euro of EBITDA above the floor.

The second variant starts with the valuation factor. The overage above the floor is multiplied by a factor or multiple, for example incremental EBITDA × 6.0. That, too, is mathematically a linear formula. If a cap is added, a cap-saturation point can be derived: with a EUR 3 million cap and a 6.0x factor, the cap is already exhausted EUR 500,000 above the floor. Conversely, in a base-amount structure, the implied factor is the base amount divided by the distance between the floor and the 100% payout metric.

The difference is therefore less mathematical than commercial. A base-amount approach feels like a defined additional purchase price earned when the plan is met. A factor or multiple approach is closer to the valuation logic of the deal and can produce large amounts more quickly if the curve is steep. The SPA should not just use a label, but make the curve itself clear: floor, slope or target metric, cap and treatment of overperformance.

Year-by-year rising target curves

In some deals, the target curve is not kept constant across the entire earn-out term, but increases year by year, for example through a rising floor, rising 100% payout metric or annually increasing revenue target. That can make sense where the buyer already expects growth in the base case and the earn-out is meant to reward only true outperformance against that growth path.

From the buyer’s perspective, a rising target curve prevents the seller from being paid again for growth that was already expected. From the seller’s perspective, it is fair only if the underlying business plan is realistic and the buyer does not, after closing, effectively decide through integration decisions, budget cuts or sales priorities whether the higher targets remain achievable. In growth businesses, the issue is therefore not only the absolute metric, but also whether planning assumptions, resources and responsibilities remain consistent during the earn-out period.

Fixed target tranche with deduction

In German clauses, the linear curve is often not described as a payment above a floor, but the other way round: if a target metric is reached, a fixed earn-out tranche becomes payable; if the target is missed, the shortfall is multiplied by a factor and deducted from the tranche amount. The earn-out usually cannot become negative.

Mathematically, this is often the same logic as a linear curve between a zero point and a target value. Commercially, however, it feels different. From the seller’s perspective, the starting point is the full tranche; small misses merely reduce it. From the buyer’s perspective, the structure is attractive where no additional upside is intended above the target value. The key point is where the zero point sits: the smaller the distance between target value and zero point, the more aggressively each shortfall reduces the payment.

Binary / milestone earn-out

In a binary model, reaching the target triggers a fixed amount; if the floor or milestone is missed, nothing is paid. That is simple to draft and can fit objectively verifiable events, such as a regulatory approval, product release or identified customer contract.

The simplicity has a cost: binary models create cliff effects. A narrowly missed threshold may economically reflect almost the same business performance as a narrowly achieved threshold, but it produces a completely different payment outcome. For that reason, binary structures are often combined with linear mechanics, partial payments or rules allowing overperformance to be applied to weaker periods.

Multiple earn-out components and tranches

More complex SPAs do not always use a single earn-out formula. In practice, several components are often combined: for example an EBITDA earn-out for operating profitability, an additional revenue or ARR component for growth above a base case and a separate milestone for product approval or key customers.

Those structures should not be hidden in one large formula. It is cleaner to describe each tranche with its own metric, period, cap, due date and dispute mechanism. In the first commercial model, it is usually sensible to test individual building blocks separately; the interaction between tranches remains contract work.

Average-based earn-out

In an average-based earn-out, the reference metric is averaged over several periods. The parties thereby smooth out individual outlier years, which may make particular sense in cyclical or seasonal business models. Payment is often made only at the end of the earn-out period as a bullet payment based on the average value.

That helps against random effects. But it also prolongs uncertainty. The seller has to wait longer and trust that the buyer will run the business over several years in a way that remains compatible with the earn-out logic.

A related structure starts with a base earn-out and adjusts it at the end of the term by reference to the deviation from the average target value. If the three-year average exceeds the target, the excess is multiplied by a factor and added; if it falls short, the base amount is reduced, usually subject to a zero floor and a cap. From the buyer’s perspective, this stabilises the effective valuation multiple actually paid, but for the seller it shifts liquidity and uncertainty further towards the end of the earn-out period.

A simple numerical example shows the difference to surplus allocation: assume an EBITDA floor of EUR 5 million, a 100% payout metric of EUR 7 million and an annual maximum earn-out amount of EUR 1 million. If the target generates EBITDA of EUR 4 million in year 1 and EUR 10 million in year 2, strict annual testing produces only the full year 2 earn-out of EUR 1 million. Under a multi-year average, the measurement basis is EUR 7 million; in a simple model, that produces a single payment of EUR 1 million. If overperformance is applied, by contrast, the year 2 surplus above the 100% payout metric can compensate the year 1 deficiency. Year 2 remains fully earned and year 1 can additionally be lifted to the 100% payout metric, subject to the applicable caps.

Applying overperformance

Where overperformance may be applied, the year-by-year analysis remains in place. The parties nevertheless agree that overperformance in one period can compensate deficiencies in other periods. Contract language sometimes expresses this as applying surplus EBITDA to deficiency periods, i.e. a carry-forward or carry-back of surplus performance to weaker periods.

This is not the same as averaging. Averaging compresses the entire term into one measurement basis. Surplus allocation preserves individual periods, caps and already accrued claims; it only applies additional surplus to weaker periods. In practice, this mechanism is often designed without clawback of amounts already earned: overperformance can create additional payments, but it cannot create a negative earn-out.

The crucial question is which threshold counts as genuine overperformance. In linear formulas, that is usually the point at which the base payment is exhausted: in a base-amount structure, the 100% payout metric; in a factor or multiple structure with a cap, the cap-saturation metric. Not every euro above the floor should be used twice. In a binary model, by contrast, any surplus above the floor can be used as compensation mass because the payment is fully triggered once the threshold is met.

The parties may limit allocation to immediately preceding or following periods, or allow cumulative allocation across the entire term. Economically, that is a major difference. The further allocation reaches, the more it resembles a smoothing mechanism, without fully giving up period-by-period settlement.

From the buyer’s perspective, the direction of allocation also matters. A carry-back of later overperformance to earlier weak periods is often easier to accept than a carry-forward of early overperformance into later weak periods. The commercial reason is straightforward: a move from a weak first year to a strong second year is more consistent with the growth thesis. A strong first year followed by a decline looks like deteriorating performance. A limited carry-back can therefore be more buyer-friendly than true averaging: individual years remain visible, and a later decline is not smoothed away by earlier overperformance.

From the buyer’s perspective, the model should reflect genuine economic overperformance, not merely the effect of timing shifts or generous add-backs. The risk is obvious: the seller has an incentive to pull costs into weaker periods and push revenues into strong periods in order to create an allocable surplus. Any buyer accepting this model should therefore insist on clear rules for period cut-off effects, the treatment of add-backs and the influence of management decisions on the result.

Customer-based earn-out

Some buyers acquire above all customer relationships. In those cases, it is often unconvincing to tie the earn-out to the overall profitability of the business if that profitability will be heavily affected after closing by integration or overhead decisions. In such situations, the earn-out may be based on revenues or gross profits from identified customers, customer groups or contracts.

This is particularly useful for strategic buyers intending to realise synergies and integrate central functions. The seller then participates in the fact that “its” customers are actually retained and monetised within the new group. At the same time, the drafting burden rises sharply. What happens if prices change, cross-selling occurs, contracts migrate to another group company or customers are lost for reasons outside the seller’s sphere of influence? Anyone choosing this model needs a very precise customer definition.

Cap, floor and upside as a separate risk corridor

Cap and floor are not decorative extras. They define the economic corridor of the earn-out and, with it, the real allocation of risk. Anyone looking only at the metric often misses the more important point.

Cap

The cap is the upper limit of the earn-out. It limits the buyer’s risk and creates financing certainty, because the maximum later purchase price burden is fixed. From the seller’s perspective, a cap is usually easier to accept if the fixed purchase price at closing is high enough or if the cap only kicks in above genuine overperformance.

In factor- or multiple-based upside models in particular, a cap is almost indispensable. Without it, exceptionally strong performance could drive the variable purchase price far beyond the range originally contemplated. That may be attractive from the seller’s perspective. For buyers and financing banks, however, it is often not workable.

Floor

The term floor is not used consistently in practice. Two functions need to be distinguished.

First, floor may refer to a minimum threshold of the reference metric below which no earn-out becomes payable. That is not a payment promise, but an entry criterion. This threshold value is the real standard case: if EBITDA falls below EUR 2 million, nothing is paid. Above that, the earn-out curve begins.

Second, a floor may mean a guaranteed minimum amount that the seller receives in any event regardless of performance. This variant secures an economic minimum for the seller. It is, however, comparatively rare, because a guaranteed minimum amount economically resembles a vendor loan – in other words, it shifts risk to the buyer that no longer depends on the target’s performance. For the buyer, that means a fixed cash burden even if the business develops poorly. In German practice, this structure is therefore seen only in specific transaction settings, for example where the closing payment was deliberately kept low and the floor is intended to bridge the gap to the seller’s original price expectations.

Total cap and per-period cap

It is equally important to determine whether the cap applies in total or per period. A total cap limits the aggregate of all earn-out payments over the entire term. An exceptionally good first year may therefore already exhaust the economic room.

A per-period cap, by contrast, limits only the payment for the individual year. Example: three-year earn-out, maximum EUR 1 million per year. In that case, a very strong first year cannot “use up” the later periods. From the seller’s perspective, that is often more attractive. From the buyer’s perspective, a total cap may be easier to model, especially in volatile business models.

Upside beyond the base amount

A common mistake is to equate the base earn-out amount with the absolute maximum. That need not be the case. The parties may agree that, for example, EUR 2 million becomes payable on target achievement, but that EUR 3 million or EUR 4 million can be reached in case of overperformance. This upside feature allows the seller to participate in real overachievement without the buyer giving up an upper limit.

Economically, that is often more sensible than a rigid target curve. But it immediately raises the next question: where does upside start? In a linear base-amount structure, the additional bonus should usually begin only above the 100% payout metric; in a factor or multiple structure with a cap, only above the metric at which the cap is exhausted. Otherwise the buyer effectively pays twice for the same performance increase: once through the base formula and again through the upside bonus.

It is equally important to define what type of overperformance counts. Only organic growth, or also synergies, pricing measures by the buyer and the effects of additional capital? This is exactly where it becomes clear that cap, floor and upside should never be negotiated in isolation.

The critical SPA clauses

Earn-outs rarely fail because of the Excel file. They usually fail because of the question who may pull which levers after closing and under which rules the later calculation is performed. That is why the commercial rules need to be embedded in a precise contractual framework.

Accounting principles and calculation hierarchy

The most important clause concerns the calculation logic. Typical building blocks include a reference to consistent application of the previous accounting principles or to a sample earn-out calculation attached as a schedule. From the buyer’s perspective, this is meant to prevent historical accounting errors from being carried forward. From the seller’s perspective, it should prevent the buyer from devaluing the earn-out through new accounting or reporting rules.

In practice, a hierarchy of calculation rules works well. First come the specific definitions in the SPA, then the sample calculation, then the historic accounting and reporting practice and only lastly general HGB or IFRS principles. This order is valuable because general accounting standards alone rarely answer how intra-group charges, exceptional items, PPA amortisation or reclassifications are meant to be treated.

Conduct of business in the ordinary course

The buyer runs the business after closing, or at least has the ability to instruct management. That is precisely why the seller often asks for an obligation to conduct the business in the ordinary course (ordinary course of business) and a prohibition on measures whose principal purpose is to reduce the earn-out. This typically covers shifting revenues to other group companies, excessive management fees, non-arm’s-length intra-group service charges or exceptional burdens resulting solely from post-closing integration.

Buyers rarely accept a general veto right for the seller. That would be difficult to reconcile with the economics of an acquisition. What is more common is a negative list for particularly sensitive measures or wording under which the buyer must act in good faith and may neither intentionally circumvent nor deliberately hollow out the earn-out. The right balance can only be found on a transaction-specific basis.

Information, audit and dispute resolution rules

The seller needs access to the information on which the earn-out calculation is based. Depending on the deal, this includes monthly or quarterly reporting, access to relevant documents, a formal earn-out statement within a fixed period and a right to raise objections. Without these process rules, the substantive formula is of limited value.

The payment mechanic during a dispute also matters in practice. The undisputed portion of the earn-out should usually remain payable on time; otherwise the buyer can effectively block the entire payment by objecting to peripheral points.

Dispute resolution is just as important. The parties often appoint an independent auditor or other expert as a neutral determination expert to decide only disputed calculation issues. That is different from arbitration. The SPA should make that distinction clear. Otherwise, the first dispute is about who is entitled to decide the dispute.

Protective mechanisms for the seller

Once closing has occurred, the seller has transferred the shares. Economically, the earn-out then often remains only as an unsecured purchase price claim against the buyer or acquisition structure. Especially in longer-term or leveraged transactions, it is therefore often not enough for the seller to rely solely on information rights.

Covenants during the earn-out period

One common instrument is contractual covenants of the buyer during the earn-out period – for example restrictions on distributions, debt limits, reporting obligations or consent requirements for extraordinary measures. Because the earn-out is typically owed by the buyer (not by the target), these provisions are designed to prevent the buyer from operating or burdening the target in a way that undermines the earn-out value.

From the buyer’s perspective, however, covenants must remain workable. They are therefore usually limited in time, tied to materiality thresholds and subject to exceptions for the ordinary course of business or requirements under the financing documents. Covenants that are too tight hamper integration. Covenants that are too loose do not help the seller.

Change of control and acceleration

An acceleration clause (acceleration) is one of the classic seller protection mechanisms. The trigger should, however, be drafted precisely. In addition to a genuine change of control, the relevant cases are above all those in which the earn-out metric can no longer be measured meaningfully after a restructuring – for example because the target is merged into another group company, contributed into another legal entity or its business is substantially reorganised. In those cases, early settlement is not a sanction, but a practical necessity.

From the buyer’s perspective, there are good reasons to limit the trigger to genuine structural changes and to carve out internal reorganisations that do not affect the target’s operating business. The more precise the trigger, the lower the potential for dispute.

Early buyout (call and put)

Independently of acceleration, the parties may grant the buyer or seller the right to settle the remaining earn-out early in return for a one-off payment.

The buyer’s option (call) is the more common variant. The buyer may want a buyout if the governance obligations during the earn-out period become more burdensome than the buyout amount, for example because the buyer wants to simplify integration or end reporting obligations. From the seller’s perspective, the main risk is adverse selection: the buyer will typically exercise the option precisely when performance is strong and a high earn-out is looming. That is why the pricing mechanism is critical; common approaches are a projection formula based on the current run-rate or an independent expert valuation.

The seller’s option (put) is rarer and is usually agreed only for narrow trigger situations, for example a material breach of covenant by the buyer. It gives the seller leverage if trust in the buyer’s stewardship has broken down.

In the case of a put option in particular, the seller will as a rule have to accept a material discount to the maximum earn-out potentially achievable. That is inherent in the structure: the option only has value if it removes uncertainty over the settlement amount, and that certainty has its price.

Default interest and payment mechanics

Even well-defined earn-outs are of little use if payment remains open afterwards. Maturity, payment route and the treatment of undisputed portions should therefore be clearly regulated. A common approach is that the undisputed part must be paid on time, while only the disputed balance remains in contention.

Default interest is standard. In some cases, increased interest or other pressure mechanisms are also negotiated for late payment. That may be sensible as long as the provision remains commercially coherent and does not itself create new validity or interpretation disputes. A clear maturity mechanism is usually worth more than a spectacular penalty interest clause.

What a model does not replace

A commercial model is useful for testing cap, floor, upside, averaging and overperformance allocation. It does not decide, however, whether the chosen metric is legally well defined or whether the seller has sufficient protection after closing.

It leaves out, in particular, parallel earn-out components, multi-step milestone plans, revenue-recognition detail, add-backs, buyer-conduct covenants, security, tax treatment, employment-law retention issues and the concrete dispute mechanism. In the SPA, those points are often more important than the formula itself.

How long the earn-out period should be

The term is a classic compromise. An earn-out that lasts only one year makes the result vulnerable to random effects, project timing shifts and one-off market movements. An earn-out lasting four or five years stretches the seller’s tie-in too far and amplifies the buyer’s influence on the outcome.

That is why parties often end up at two to three years. That is long enough to smooth fluctuations and short enough to keep governance and information rights still meaningfully workable. Of course, deviations are possible. A customer-based earn-out may make sense after only 12 months; regulatory or product-related milestones sometimes require longer.

The longer the period, the more governance the earn-out needs.

Tax treatment: think about it early

Earn-out payments are, in principle, part of the seller’s disposal proceeds. In the sale of a partnership interest or an entire business, § 16 EStG is therefore usually relevant; in the case of a substantial shareholding in a corporation, typically § 17 EStG. The key tax question is often whether the earn-out qualifies as a purchase price claim subject to a condition precedent or as a subsequent purchase price increase.

For the sale of a partnership interest, the German Federal Fiscal Court has held that profit- or revenue-dependent earn-out payments are generally taxable only when received as subsequent business income and do not retrospectively increase the disposal gain in the year of sale. That is an important reference point, but it does not remove the need to analyse the concrete structure, especially in § 17 EStG cases, mixed purchase price components or arrangements with an interest element.

Particular care is required where the earn-out is effectively linked to the seller’s or management’s continued employment. In those cases, the line between variable purchase price, remuneration, retention bonus and differently taxed consideration can become more difficult than the commercial formula suggests.

This is not an issue to leave for final drafting. Especially with variable purchase price components, hybrid models with an interest element or longer terms, tax advisers should be involved early so that the share purchase agreement is properly aligned from a tax perspective and does not have to rely on improvised side solutions at the last minute.

Delineation: vendor loan and rollover equity

Earn-out, vendor loan and rollover equity are sometimes mentioned in the same breath because all three solve the same basic problem: the buyer cannot or does not want to pay the full purchase price immediately, and the seller is willing to leave part of the proceeds in place for the time being. Structurally, however, they are different – and those differences determine the seller’s risk profile.

The vendor loan is a fixed purchase price component that is deferred. The amount is fixed; there is no dependence on performance. The repayment risk is the buyer’s credit risk, not the target’s operating risk. The seller is a creditor, not a risk bearer of the company’s future development. That is why security – ranking, collateral and covenants – is the decisive negotiation issue.

Rollover equity is not a purchase price component at all, but a genuine shareholder position: the seller reinvests part of the proceeds into the new structure – typically in private equity transactions where management or former shareholders remain invested with a minority stake in the holding company. The seller participates in the future enterprise value both on the upside and on the downside. Ratchet structures are often added, shifting the participation percentage through waterfall provisions depending on the fund’s achieved return.

The earn-out is a variable purchase price component that depends on a specific post-closing metric – operating profit, revenue or a milestone. The seller is no longer a shareholder, but retains an economic participation in future performance, though without the rights and duties associated with shareholder status and usually subject to a firm upper limit on the additional proceeds that can be achieved.

In practice, all three instruments may appear in combination. A private equity buyout may include an upfront purchase price, vendor loan, earn-out and management rollover at the same time. The more instruments are combined, the more important it becomes to align their mechanics.

Common mistakes

1. The metric is named, but not defined. EBITDA, EBITA or gross profit sound familiar, but without add-backs, delineations and a worked example they are often too indeterminate.

2. The metric does not match the value thesis. EBITDA for a highly capital-intensive business, or overall profitability for a deal fundamentally driven by customer relationships, can easily miss economic reality.

3. Cap and floor are mentioned only in passing. In particular, whether a total cap or a per-period cap applies and whether there should be genuine upside beyond the base amount can decide outcomes worth millions.

4. Group integration and intercompany issues are left unregulated. Management fees, intra-group charges, cost allocations, synergies or purchase price allocation effects are often the real drivers of disputes after closing.

5. There is no clear dispute resolution mechanism. Without fixed deadlines, an objection procedure and a neutral determination expert process, dispute resolution may become unnecessarily protracted or fail altogether.

6. The seller relies only on information rights. In longer-term structures, security, covenants, acceleration provisions (including restructuring scenarios), early buyout options and default interest may be economically more important than a mere inspection right.

7. Tax treatment is reviewed too late. What looks clean as an earn-out under civil law may create problems in a completely different place for tax purposes.

8. The parties do not test the mechanics on examples. An earn-out should always be run through several scenarios before the drafting is finalised. The earn-out calculator can be a useful starting point for that exercise.

An earn-out can bridge valuation uncertainty in a sensible way and allow both sides to reach an agreement that might not be possible without a variable purchase price component. But it is a good instrument only if metric, payout model, risk corridor and governance are conceived as one coherent whole.

For an initial view of the commercial side, the earn-out calculator can help: it models cap, floor, upside and different payout variants in concrete figures. The rest remains contract work. In earn-outs, disputes rarely arise from the formula itself, but almost always from the way the formula has been defined.