Locked Box
A pricing mechanism where the purchase price is fixed based on a pre-close "locked box" balance sheet date, with no post-closing working capital adjustment — common in European M&A, less common in US SMB deals.
Full Definition
Locked box contrasts with the standard US "completion accounts" approach. In completion accounts (also called "closing accounts"), the purchase price adjusts after closing based on final working capital, debt, and cash measured at the closing date. In locked box, the purchase price is set at signing based on a specific historical balance sheet date — the "locked box date" — and doesn't change post-close. The seller retains economic risk and benefit from the locked box date to closing.
How it actually works: Mechanics: (1) parties agree on a specific historical date (often the last completed month-end before signing); (2) the balance sheet at that date determines cash, debt, and working capital for pricing; (3) the seller commits that from the locked box date to closing, no value will be extracted beyond ordinary course business; (4) specific permitted and prohibited "leakage" items are defined in the agreement; (5) purchase price is fixed and paid at closing — no post-close adjustment.
Because there's no post-close adjustment, the buyer takes on some risk that the business between signing and closing operates as represented. To protect against value leakage, the agreement includes "no leakage" covenants — restricting dividends, related-party payments, asset sales, and other value extraction — and a specific indemnity for any leakage that does occur.
Locked box is dominant in European and UK M&A, estimated at 70%+ of deals there. In US M&A, it's less common (perhaps 10-15% of deals) but growing, especially in sponsor-to-sponsor transactions where speed to close and certainty matter.
Seller vs. Buyer Perspective
Locked box is seller-friendly in that it eliminates post-close adjustments — you know exactly what you're getting at closing, no true-up surprise. It also usually means faster closing (no post-close accounting reconciliation). Tradeoffs: (1) you lose the benefit of any operational improvements between locked box date and close (those flow to buyer); (2) you're responsible for not "leaking" value in the gap period — a restrictive commitment; (3) buyers typically price this uncertainty into their offer, sometimes 2-4% below a completion accounts equivalent. If you have strong faith in the locked box balance sheet and want certainty, push for locked box. If your business has volatile working capital or significant growth, completion accounts captures more value.
Locked box simplifies your diligence and operations post-close — no three months of accounting reconciliation after close. It also makes the deal price more certain. Risks: (1) you don't get the benefit of value increases between signing and closing; (2) you need robust "no leakage" protection; (3) you need to diligence the locked box balance sheet carefully because it's what you're paying for. Build in a ticking fee — daily interest-like payment from the seller to buyer if closing is delayed — to preserve economics of the deal.
Real-World Example
A UK-based $8M EBITDA manufacturing business is being sold to a European PE firm. Locked box date: March 31. Signing: June 15. Closing: August 30. Locked box balance sheet shows working capital of £6.8M, debt of £2.1M, cash of £1.8M. Enterprise value £58M. Purchase price at closing: £58M − £2.1M debt + £1.8M cash = £57.7M equity value, fixed. The agreement includes restrictive covenants on leakage: no dividends, no related-party payments, no asset sales outside ordinary course, capex within budget. Between March 31 and August 30, business grew EBITDA run-rate by 6% through a new customer win. That value accrues to the buyer. A ticking fee of $10K/day applies to delayed closing past planned August 30 date, compensating for delay. Deal closes at agreed August 30 on agreed price — simple, no post-close adjustment, no reconciliation disputes.
Why It Matters & Common Pitfalls
- !Gap period risk. The longer the period between locked box date and close, the more exposure to changes. Ideally under 90 days.
- !Leakage definition. What constitutes prohibited leakage vs. permitted ordinary course is heavily negotiated and often disputed.
- !Ticking fees. Buyer compensation for delayed closing preserves deal economics. Typical range 5-8% annualized.
- !US market resistance. US counsel and dealmakers often default to completion accounts. Education and alignment needed for locked box deals.
- !Financing coordination. Lenders need to understand locked box structure for borrowing base calculations and debt sizing.
- !Working capital volatility. Businesses with volatile working capital (construction, inventory-heavy, seasonal) may be hard to price on locked box basis.
- !Post-closing deliverables. Without a completion accounts process, buyers don't get post-close audit confirmation of balance sheet accuracy — diligence must be thorough.
Frequently Asked Questions
What is a locked box in M&A?↓
What's the difference between locked box and completion accounts?↓
What is leakage in a locked box transaction?↓
Related Terms
Completion Accounts
The dominant US M&A pricing mechanism: the purchase price is adjusted after closing based on the actual balance sheet at the closing date, measuring working capital, cash, and debt. Completion accounts are contrasted with the locked box mechanism (common in European deals) where price is fixed pre-close. Most US SMB deals use completion accounts — see [Working Capital Adjustment](#working-capital-adjustment) and [Post-Closing Adjustment](#post-closing-adjustment) for detailed mechanics.
Working Capital Adjustment
A purchase price adjustment comparing the business's working capital at closing to an agreed target (the "peg") — with any shortfall deducted from seller proceeds and any surplus added.
Working Capital Peg
The agreed target level of working capital the seller is expected to deliver at closing — the benchmark against which actual closing working capital is measured for purchase price adjustment.
Post-Closing Adjustment
Reconciliation of estimated closing balances (working capital, debt, cash) to final actual amounts, with net difference paid between buyer and seller — typically finalized 60-120 days after closing.
Cash-free, Debt-free
A standard M&A pricing convention where the seller keeps all cash at closing and pays off all debt, so the purchase price reflects only the value of the operating business itself.
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Disclaimer: The information provided on this page is for educational and informational purposes only. It should not be considered financial, legal, or investment advice. Business valuations depend on many factors specific to each situation. Always consult with qualified professionals — including business brokers, CPAs, and M&A attorneys — before making acquisition or sale decisions. LegacyVector is not a licensed broker, financial advisor, or attorney. Data shown may be based on limited samples and may not reflect current market conditions.
LegacyVector Research Team
Reviewed by M&A professionals · Updated April 2026