Why "Clean It Up In Diligence" Is The Most Expensive Sentence In M&A

"Clean it up in diligence." A founder said this to me last month, six weeks before LOI, when I asked about a $1.2M ambiguity sitting inside his customer-contract revenue recognition. He had said it before, to his CPA, to his banker, and to a board member who should have known better. By the time the buyer's diligence team got to it, the ambiguity had cost him about eleven percent on a transaction he had been preparing for for over two years.

This is the most expensive sentence in M&A. It is so common we built a working paper around the pattern.

The paper is The Preparation Gap in Early 2026: Post-LOI Adjustment Patterns in Lower-Middle-Market Transactions, published on SSRN April 3, 2026 (DOI 10.2139/ssrn.6515478). The named finding is the Preparation Gap, defined as the difference between what a founder thought their business showed and what diligence proves it can show, expressed as a percentage of the original LOI valuation. The data set covers transactions in the $5M-$100M enterprise value band, and the central observation is that the Preparation Gap is not random. It is structurally predictable, measurable months before LOI, and addressable if it is named early enough.

The reason the sentence is so expensive is leverage. Before LOI, the founder holds the leverage. The buyer is competing for the right to be in the room. After LOI, the leverage flips. The buyer holds the option to walk, and they hold a clock. Every issue surfaced after LOI is now priced at the buyer's price, with the founder's exit clock running. That is how an eleven percent adjustment gets accepted on a deal that was eight months from close.

The standard founder response is to point at the lawyer, the CPA, the banker, or the board, and ask why nobody flagged the ambiguity earlier. It is the wrong question. The right question is, who was the person whose job it was to look across all of them?

In most lower-middle-market transactions, the answer is nobody. The CPA optimizes for tax. The banker optimizes for the transaction. The lawyer optimizes for the contract. None of them are optimizing for the gap between them. The gap is where the Preparation Gap lives.

Three patterns repeat across the deals we looked at:

The first is customer-concentration math that is technically accurate but is going to read differently to a buyer than it reads to a founder. A founder sees a customer who has been there ten years and assumes the buyer will too. The buyer sees a churn risk indexed against the founder's earnout and discounts accordingly. The data lives in the same general ledger but the conclusion does not.

The second is working capital. Founders who have never sold a company often do not realize that working capital is a price-adjustment mechanism. The target gets set, the actual gets measured, the delta gets paid in cash at close. Most founders do not know what their normalized working capital looks like across seasonality until the buyer tells them, which is the wrong moment to find out.

The third is owner add-backs. Every founder we work with has add-backs. Some are clean and defensible. Some are arguments the buyer is going to win at the negotiating table the moment a Big Four QoE provider weighs in.

None of these are exotic. They are the working surface area of every deal in this enterprise value band. What makes them expensive is timing. Surfaced eight months before LOI, they become preparation work. Surfaced six weeks after LOI, they become the buyer's leverage on price.

The fix is structural. Not heroic. Not expensive. A buyer-lens read of the business, run by someone whose job is the gap between the CPA, the banker, the lawyer, and the board. Eight to twelve months before any conversation with a buyer. That read does three things: it finds the issues that will cost real percentage points if surfaced in diligence; it gives the founder time to fix what is fixable; and it gives the founder time to reframe what is not.

The founders we have walked through this read do not eliminate the Preparation Gap. They convert it from an after-LOI price adjustment into a before-LOI preparation choice. The number does not always go to zero. It goes to a number the founder controls.

The working paper goes deeper into the structural drivers and the data behind the named finding. The point of this piece is simpler: the most expensive sentence in M&A is "we'll clean it up in diligence." By the time diligence starts, the buyer holds all the leverage. The work that costs ten percent later is work that costs zero earlier. The founders who treat preparation as the first phase of the transaction, not a preamble to it, end up keeping the percent.

That is not a hard rule. It is what the data keeps showing.