M&A Transaction Costs: What to Budget When Acquiring a Business

A transaction cost is money spent to investigate, negotiate, finance and complete an acquisition. It goes to third parties: law firms, accounting firms, technical reviewers, brokers and advisers, lenders, insurers and government agencies. None of it buys any part of the target. That is what separates it from the purchase price, and it is why accountants usually expense acquisition costs rather than adding them to the value of what was bought, depending on the accounting framework and deal type.

Budgeting starts with a clean separation. On one side sits the price: the enterprise value agreed in the letter of intent, adjusted for cash, debt and working capital, and paid partly at completion, partly later. On the other side sit the costs: the fees each party pays to reach that price. Our guide to enterprise value vs equity value covers how the price side bridges to cash at completion.

The table below lists the main categories for a private acquisition. "Typically" means the common starting position, not a rule: allocation is negotiated and recorded in the letter of intent and the purchase agreement.

Regulatory costs you can look up

Some costs are published. In the United States, filing a Hart-Scott-Rodino premerger notification carries a fee set by transaction size. The Federal Trade Commission's 2026 schedule (opens in a new tab) starts at $35,000 for transactions under $189.6 million and rises to $2,460,000 at $5.869 billion or more. The FTC says the acquiring person pays at filing, though the parties may agree to split it.

In the UK, buying existing shares in a UK company usually carries Stamp Duty or Stamp Duty Reserve Tax of 0.5% (opens in a new tab) of the price paid, which matters on share deals and does not arise in the same way on an asset purchase. Deals touching sensitive sectors may also need a notification under the National Security and Investment Act (opens in a new tab). Rules differ in every jurisdiction, so the regulatory line needs confirming with counsel for each country the target operates in.

Three items regularly turn up in cost budgets when they belong in the price model.

• Escrow and holdbacksPart of the price held back, by a third-party agent or by the buyer, to cover warranty claims or adjustments. If no claim is made it is released to the seller. The escrow agent's fee is a transaction cost; the escrowed money is not. See W&I insurance vs escrow.
• Working-capital adjustmentA true-up of the price so the buyer receives a normal level of working capital at completion. It can move the price up or down. The NWC peg calculator shows how a peg is set; locked box vs completion accounts covers the mechanism.
• Deferred and contingent considerationSeller notes, deferred payments and earnouts are price paid later. They affect funding and risk, not the fee budget. Model them with the earnout modelling tool, and see seller financing for note protection.

Acquisition spend is uneven. Very little is committed before a letter of intent. Most diligence and drafting happens in the exclusivity period, and that is where a failed deal hurts most. Financing and insurance costs often fall due at signing or completion, and some are only payable if the deal closes.

The money at risk in stages 3 and 4 is why exclusivity terms matter. Buyers sometimes negotiate expense reimbursement if a seller withdraws without cause during exclusivity, and sellers sometimes ask for a reverse break fee if a buyer fails to close for financing reasons. Neither is standard in smaller private deals, and both are worth raising before the LOI is signed rather than after. Our LOI teardowns and the LOI value decoder show where those terms sit.

The worksheet below uses hypothetical figures for a single-entity, single-country software business bought for $20 million of enterprise value with partial bank financing and a W&I policy. It is a format, not a benchmark: real quotes vary widely with complexity, jurisdiction and provider, and a buyer should replace every line with written quotes.

Read the worksheet by column. "Stage committed" tells you when the cash goes out. "Contingent on close?" tells you how much of it you lose if the deal dies. In this hypothetical, roughly $450,000 of the budget is exposed before signing.

Quotes are rarely comparable on headline price. The questions below expose the differences that drive the final bill.

1. 01ScopeWhat exactly is included, and what triggers a change order? Ask for scope in writing, by workstream.
2. 02Fee basisFixed, capped, phased or hourly? If hourly, what is the estimate and who approves overruns?
3. 03Abort termsWhat do you charge if the deal stops at each stage? Is there a reduced abort fee?
4. 04StaffingWho will do the work, and at what seniority? How much partner time is assumed?
5. 05RelianceWill the report be addressed to, or relied upon by, our lender and insurer? Reliance letters sometimes cost extra.
6. 06TimingCan you meet the exclusivity timetable? What happens to the fee if the timetable slips?
7. 07OverlapWhich questions will another provider also cover? Overlap between QoE, tax and legal diligence is common and avoidable.
8. 08ConflictsHave you acted for the seller, the target or a competing bidder?

• Gate the diligenceRun the cheapest disqualifying checks first: revenue quality, customer concentration, key contracts. Commission the expensive workstreams after the red-flag review passes.
• Use a data-room indexA complete index early reduces repeated requests, which is where advisers' hours disappear.
• Ask for a vendor packIf the seller has a vendor QoE or a legal fact book, reviewing it is usually cheaper than rebuilding it, though most buyers still test it independently.
• Set walk-away pointsAgree in advance which findings end the deal. It keeps sunk cost from driving the decision.

For the financing side of the budget, the capital stack builder and the deal structure comparison model how debt, equity and seller paper combine; this page deliberately does not repeat them. The due diligence checklist lists what each diligence workstream should cover.