Every diligence process ends with some questions still open. Will the largest customer renew next year? Will the new product line keep growing once the founder stops selling it personally? Is last year's margin improvement durable or a one-time effect? In a lower middle-market deal, where diligence budgets are limited and sellers are often first-time sellers, those open questions are normal.
What separates a well-structured deal from a poorly structured one is what happens to those questions next. Too often, buyers either discount the price to cover every uncertainty, which loses the deal, or ignore the uncertainty to win the deal, which risks overpaying. Earnouts and seller notes offer a third option: pay for the uncertain part of the value only if it turns out to be real.
Start with the diligence gap, not the structure
The most common mistake is reaching for an earnout because the price gap is wide, without being specific about why. Structure works best when it is tied to a named uncertainty that diligence surfaced and could not resolve. Before proposing any contingent consideration, write down each open question, how much value depends on it, and when it will be answered. That list tells you which tool to use.
- A specific future event (a contract renewal, a regulatory approval, a product launch) often suits an earnout tied to that event.
- General confidence in earnings quality or the seller's representations usually suits a seller note, with rights to offset against it for indemnity claims.
- Dependence on the seller continuing to work in the business may suit a rollover equity stake or a consulting arrangement more than an earnout.
Earnouts: where they work and where they fail
An earnout works best when the metric is simple, measurable, and mostly within the seller's control during the earnout period. Revenue from a defined set of customers, gross profit from a specific product line, or renewal of named contracts are all reasonable. The shorter the period, typically one to two years, the less room for disagreement.
Earnouts fail most often on EBITDA-based targets. Once the buyer owns the business, it controls cost allocation, hiring, pricing, and integration decisions, all of which move EBITDA. The seller will reasonably argue that the buyer's decisions caused a miss, and the buyer will argue the opposite. Disputes over earnouts are common, and most of them trace back to a metric that the two parties could each influence.
A few drafting points reduce that risk considerably:
- Define the metric precisely, including accounting policies, treatment of acquired or lost customers, and what happens if the business is integrated with another.
- Include a worked example in the agreement showing exactly how the earnout would be calculated on historical numbers.
- Consider tiered or linear payouts rather than a single cliff, so a near miss does not produce an all-or-nothing dispute.
- Agree on operating covenants, if any, that limit what the buyer can change during the earnout period, and be realistic about what you are willing to accept.
- Set a clear dispute mechanism, usually an independent accountant, with a defined scope.
Seller notes: underused and often better
A seller note defers part of the purchase price as a loan from the seller to the buyer, repaid over several years with interest. It does not depend on performance targets, so it avoids most earnout disputes, but it still keeps the seller financially aligned with the business after closing.
For buyers, the seller note has three practical benefits. It reduces the equity and senior debt needed at closing. It signals to lenders and capital partners that the seller believes in the business. And, if the purchase agreement allows it, it creates a source of recovery for indemnification claims, because the buyer can offset amounts owed against the note instead of trying to recover money already paid.
Senior lenders will usually require the note to be subordinated, with limits on payments if covenants are breached. Those terms should be discussed with the seller early, because a seller who expected regular payments may be surprised by standstill provisions.
Rollover equity: alignment for the long run
Where the open question is really about the next five years rather than the next twelve months, rollover equity can be the most natural structure. The seller keeps a minority stake and participates in the eventual exit. It works well when the seller will remain involved and when the buyer's plan depends on the seller's knowledge or relationships. It works less well when the seller wants a clean exit, or when minority rights and exit timing have not been clearly agreed.
Presenting structure to a seller
How structure is presented matters as much as how it is drafted. First-time sellers often see an earnout as a sign the buyer does not believe them. Framing helps: the structure lets the buyer pay a higher total price than it could justify in cash at closing, and it rewards the seller for the outcomes they are most confident about. A seller who believes the largest customer will renew should be comfortable being paid when it does.
Tie every piece of contingent consideration back to something specific you learned in diligence. That makes the proposal feel like a response to the facts rather than a negotiating tactic, and it keeps the conversation on the business rather than on trust.
Used this way, structure is not a way to lower the price. It is a way to match the price to what diligence could and could not confirm, which is exactly what it is for.