Locked Box vs. Closing Accounts: How Buyers and Sellers Fix the Purchase Price

You agree to sell your company for $12 million on March 1. The deal closes on June 15, and in between, the business earns another $400,000 in profit. Who keeps that money — you or the buyer? The answer is not in the headline price. It is in a few pages of the purchase agreement that most first-time sellers skim: the price mechanism. Pick the wrong one and you will hand over three months of profit for free, or spend six months after closing fighting over the working capital count.

There are two standard mechanisms, and they answer the question in opposite ways. Under closing accounts, the price is estimated at closing and trued up afterward to reflect what the business actually looked like on closing day — you keep the interim profit, but you pay for the interim deterioration too. Under a locked box, the price is frozen against an old balance sheet and never adjusted — the buyer's economics start ticking months before they own the company, and that $400,000 belongs to them.

This guide explains how each mechanism works, what "leakage" and the "equity ticker" actually do, which side each structure favors, and the negotiation points that decide whether you leave interim value on the table.

The One Concept That Explains Both: The Effective Date​

Every deal has a signing date (pen hits paper) and a closing date (ownership changes hands). The price mechanism adds a third date that matters more than either: the effective date, the day economic ownership is deemed to transfer from seller to buyer.

• In a closing accounts deal, the effective date is the closing date. Profits earned and cash generated up to the moment of closing belong to the seller; the buyer starts owning the economics when they start owning the shares.
• In a locked box deal, the effective date is a historical date before signing — the locked box date, usually the date of the last audited or quarterly balance sheet. From that day forward, the buyer is treated as the economic owner even though the seller still legally runs the company.

Same enterprise value, same closing date — but the effective date decides who pocketed the spring. Everything else in the mechanism is machinery to enforce that choice.

How Closing Accounts Work: Estimate Now, True Up Later​

Closing accounts are the default in the United States for a reason: they measure reality instead of forecasting it. The mechanics run in three steps.

1. Agree a formula, not a number. The purchase agreement defines enterprise value, then specifies the bridge to equity value: add cash, subtract debt and debt-like items, and adjust for working capital against an agreed target (the "peg," often a 12-month average of normalized working capital). It also spells out exactly how each line item gets counted — which accounting policies apply, what counts as debt, how inventory is valued.

2. Pay an estimate at closing. Since nobody has audited closing-day numbers on closing day, the seller delivers estimated closing accounts a few days before, and the buyer pays the price those estimates imply.

3. True up after closing. Within 60 to 90 days, the buyer (now in control of the books) prepares final closing accounts. If actual working capital beat the peg or debt was lower than estimated, the buyer pays the seller the difference; if the numbers came in light, the seller refunds the buyer, usually out of an escrow funded at closing.

The advantage is precision: the price reflects the company's actual financial position at closing, so interim profits flow to the seller through higher cash and working capital. The cost is everything after closing — the expense of preparing and reviewing two sets of accounts, weeks or months of negotiation, and genuine dispute risk over judgment calls like inventory obsolescence reserves or revenue cut-off. Working capital adjustments now appear in more than 90 percent of US private-target deals, up from about half a decade ago, according to SRS Acquiom's deal-terms research — so if you sell a US business, this is almost certainly the machinery you will live with.

How a Locked Box Works: A Fixed Price on an Old Balance Sheet​

A locked box deal is a fixed-price deal. The equity value is negotiated once, printed in the purchase agreement at signing, and never adjusted — not for cash, not for debt, not for working capital. What makes that possible is the locked box balance sheet, a recent historical balance sheet (often the last audited year-end or quarter) whose date becomes the locked box date.

Because cash, debt, and working capital are already known on that date, there is nothing left to measure. But the seller keeps operating the company for months after the effective date, so the agreement replaces the post-closing audit with three contractual controls:

Leakage: the "don't touch the box" rule. Leakage is any extraction of value from the business between the locked box date and closing that flows to the seller — dividends, management fees to the seller's holding company, bonuses paid to owner-managers, assets sold to the seller below market value, or the company paying the seller's deal costs. The agreement defines it in detail and backs it with a dollar-for-dollar indemnity: every dollar of leakage the buyer finds, the seller repays. No materiality threshold, no basket, no cap negotiation — a dollar out is a dollar back.

Permitted leakage: the pre-priced exceptions. Some outflows are expected and already reflected in the agreed price — ordinary-course salaries, routine operating expenses, a pre-agreed dividend, disclosed management fees. These are listed explicitly as permitted leakage, and the negotiation over this list is where much of the deal's real pricing happens: sellers push for broad carve-outs, buyers insist each item be narrowly defined and capped.

The equity ticker: rent for the buyer's money. Since the buyer is paying a price set months earlier while the seller held the cash in the meantime, sellers typically negotiate a ticking fee (also called an equity ticker or interest charge) — interest on the equity value, or a daily rate tied to expected cash generation, accruing from the locked box date to closing. It compensates the seller for the time value of money and expected interim profit. But note what it is: a forecast, negotiated before the fact. If the business outperforms the forecast, the buyer keeps the surplus; if it underperforms, the seller still collects the ticker.

The Core Tradeoff: Certainty Against Value Drift​

Strip away the jargon and the locked box is not really a pricing tool — it is a risk-allocation tool. It answers "who bears the interim period?" with "the buyer, from a date in the past." That creates two mirror-image exposures:

The seller trades interim upside for certainty. Every dollar of profit the business earns between the locked box date and closing accrues to the buyer. For a stable company with a two-month gap, the give-up is small and the ticker roughly covers it. For a fast-growing business, a seasonal peak, or a six-month regulatory wait, the seller can forfeit a meaningful slug of value they created — value a closing-accounts deal would have handed them through the true-up. Sellers routinely underestimate this drift because the headline price feels fixed and final.

The buyer trades a windfall chance for downside risk. The buyer pockets any interim outperformance for free, which is why buyers love locked boxes on steady, recurring-revenue businesses. But there is no true-up protecting them either: if working capital collapses, a big customer churns, or debt creeps up before closing, the buyer absorbs it, with only the leakage indemnity — which covers extraction, not deterioration — as protection.

The ticker softens the asymmetry but cannot eliminate it, because it prices expected performance while reality delivers actual performance. When the two diverge, one side has mispriced the interim — and the structure offers no mechanism to correct it.

Which Side Does Each Mechanism Favor?​

The honest answer is that neither mechanism is inherently buyer- or seller-friendly; each favors whoever the interim period favors. But the patterns are consistent enough to state plainly:

The locked box favors the seller when the priority is a clean exit: a fixed number at signing, no escrow held back for adjustments, no post-closing audit of their books, and downside protection if the business stumbles before closing. The same box favors the buyer when the business is humming — recurring revenue, a strong quarter, a short fuse to closing — because every dollar of interim performance arrives free with the shares.

Closing accounts favor whoever wants the price to match reality. Sellers in a growth spurt keep their upside. Buyers of volatile or seasonal businesses are protected from paying a January price for a June company. The price of that fairness is months of post-closing process and the real possibility of a fight over the numbers.

Market practice reflects these incentives. In Europe, locked boxes appear in roughly 43 percent of private equity deals but only about 16 percent of strategic transactions, and Latham's market study found the mechanism in up to half of European deals overall. The logic is visible in the split: financial sponsors prize fixed pricing and fast, certain closes — and as future sellers themselves, they like a mechanism that delivers clean exits — while strategic buyers, facing integration risk and longer timelines, more often insist on closing accounts. In the US, closing accounts remain the overwhelming default, with locked boxes surfacing mainly in competitive auctions and sponsor-to-sponsor deals.

When Each Mechanism Fits — and When It Doesn't​

Reach for the locked box when the business is stable and its numbers are trustworthy: audited financials, predictable working capital, a short signing-to-closing gap, and no carve-out accounting. Auctions favor it because bidders can offer genuinely comparable fixed prices. Cross-border deals with UK or European parties will often expect it as the starting point.

Insist on closing accounts when the gap is long, the business is seasonal or volatile, the balance sheet needs disentangling (carve-outs, related-party accounts, incomplete inventory records), or reporting systems are thin — the classic lower-middle-market profile, where both the historical baseline and the interim forecast are harder to validate. As a rule of thumb, locked boxes get uncomfortable when the locked box date sits more than six to nine months before closing: too much can drift, and too much leakage can hide, across that span.

A hybrid is always available — a locked box with a targeted adjustment for one volatile item, or closing accounts with a tightly-collared working capital band — but hybrids need the same discipline as the pure forms: define the item, define how it is counted, and define who prepares the numbers.

Negotiating Checklist: The Dials That Actually Move Money​

Whichever mechanism you accept, the headline enterprise value is only half the price. The other half hides in these terms:

If you are the seller in a locked box:

• Push the locked box date as close to signing as possible — every extra week of drift is value you fund and the buyer keeps.
• Price the ticking fee off realistic interim forecasts, not a token interest rate. If the business is growing, the ticker should reflect earnings, not just the time value of money.
• Negotiate permitted leakage broadly and explicitly. Anything ordinary-course that is not listed is a future indemnity claim; get salaries, bonuses, and planned distributions named and capped in the agreement.
• Keep the leakage definition tied to value flowing to you, not to every intra-group movement in a business you still have to run.

If you are the buyer in a locked box:

• Diligence the locked box balance sheet as if you were buying that date's company — because economically, you are. Challenge debt-like items, provisions, and cut-off.
• Keep permitted leakage narrow, itemized, and capped, and require the seller's leakage memo before closing.
• Demand interim operating covenants with teeth: run the business in the ordinary course, no unusual commitments, no starving capex or stuffing receivables to flatter the numbers you already paid for.

If either side is in closing accounts:

• Fight hardest over the working capital peg and the counting rules. A well-set peg produces little or no adjustment; a sloppy one manufactures a dispute. Agree sample calculations with real numbers before signing.
• Nail down who prepares, who reviews, and who breaks ties — typically buyer prepares, seller reviews, and an independent accountant resolves deadlocks — plus the escrow that funds a downward adjustment.

Tracking the Interim Period in Your Books​

Here is where plain-text accounting earns its keep for the seller. Between the locked box date and closing, you are running a company whose economics belong to someone else, under an agreement that penalizes every unlisted dollar flowing your way. That demands a sharper separation than most monthly closes: every payment to yourself, your holding company, or your affiliates must be classifiable at a glance as permitted leakage or a future indemnity.

One workable pattern is a dedicated branch of accounts for the interim period, so the leakage memo practically writes itself:

2026-03-01 * "Locked box date - opening position per locked box balance sheet"
  Assets:Operating:Cash                              412,000.00 USD
  Liabilities:Seller:Leakage-Tracker                 -412,000.00 USD
 
2026-04-15 * "Monthly management fee to seller holdco (permitted leakage, SPA Sch 4.2)"
  Expenses:Interim:Permitted-Leakage:Management-Fees   25,000.00 USD
  Assets:Operating:Cash                               -25,000.00 USD
 
2026-05-02 * "Q1 dividend to seller (permitted leakage, capped at 60,000)"
  Expenses:Interim:Permitted-Leakage:Dividends         60,000.00 USD
  Assets:Operating:Cash                               -60,000.00 USD
 
2026-05-20 * "Company paid seller's deal counsel - NOT permitted, accrues as leakage"
  Assets:Interim:Leakage-Owed-By-Seller               18,500.00 USD
  Assets:Operating:Cash                              -18,500.00 USD

With the interim branch isolated, a single query over Expenses:Interim:Permitted-Leakage reconciles against the SPA's permitted-leakage schedule, and Assets:Interim:Leakage-Owed-By-Seller is the indemnity number — no forensic reconstruction from the general ledger three weeks before closing. If you are new to Beancount's syntax, the project documentation covers accounts, transactions, and queries from first principles.

Buyers can mirror the structure on their side: book the ticking fee accrual, the leakage indemnity receivable, and the locked-box-date opening balances as distinct postings, so the first post-closing audit ties straight back to the purchase agreement instead of dissolving into goodwill math.

The Question to Ask Before You Sign​

A locked box and closing accounts start from the same enterprise value and can end thousands — sometimes hundreds of thousands — of dollars apart, purely on who owned the months between the balance sheet and the closing dinner. Before you agree to either, run your own interim forecast, price the ticker or the peg against it, and ask the only question that matters: if the business beats this forecast, who gets the extra — and am I being paid for giving it away? Get that answer in the agreement, in numbers, and the mechanism becomes what it should be: plumbing, not a second negotiation.