Locked Box

What Is a Locked Box?

A locked box is a pricing mechanism in which the purchase price is determined by reference to a set of accounts prepared as at a historical date — the “locked-box date” — and is not subject to any post-closing adjustment. From the locked-box date, the economic interest in the business effectively transfers to the buyer, even though legal completion occurs later. The price is “locked” and the “box” is sealed: no value should leak out of the business between the locked-box date and closing.

The locked-box mechanism originated in European private equity transactions and has become the dominant pricing approach in European and Asia Pacific M&A (Corporate Finance Institute). Its appeal lies in price certainty — both parties know the exact purchase price at signing, eliminating the post-closing disputes that frequently accompany completion accounts mechanisms.

For practitioners, understanding the locked box is essential because the choice between locked box and completion accounts is one of the most consequential structural decisions in any transaction — a theme covered in detail in our M&A process guide. It determines how risk is allocated, how the SPA is drafted, and where the points of negotiation will concentrate.

How a Locked Box Works

The Mechanics

The locked-box mechanism operates through the following framework:

1. Locked-box accounts — a set of accounts (typically audited or reviewed) is prepared as at the locked-box date, which is usually the most recent financial year-end or quarter-end preceding the transaction
2. Price determination — the parties agree on an equity price derived from the locked-box accounts, applying agreed adjustments for enterprise value, net debt, cash, and working capital as at the locked-box date
3. Permitted leakage — the SPA defines specific categories of payments that the seller is allowed to extract from the business between the locked-box date and closing (e.g., agreed management fees, ordinary-course dividends, pre-agreed bonuses)
4. Prohibited leakage — all other value extraction between the locked-box date and closing is prohibited, with a pound-for-pound indemnity from the seller to the buyer for any breach
5. Closing — the buyer pays the fixed price and the transaction closes with no post-closing price adjustment

The Locked-Box Date

Choosing the locked-box date is a critical decision. It must be recent enough that the accounts provide a reliable picture of the business, but far enough in the past that audited or high-quality reviewed accounts can be prepared. Common choices include:

• Most recent audited year-end — provides the highest quality accounts but may be several months old
• Most recent quarter-end — more current but typically based on management accounts rather than audited figures
• A bespoke date — occasionally used where neither year-end nor quarter-end is appropriate

The gap between the locked-box date and expected closing is crucial. A longer gap increases the buyer’s risk, since the buyer bears the economic exposure of the business during this period without operational control. Buyers typically seek to minimise this gap; sellers may be less concerned since a longer gap means they benefit from a “ticker” (see below).

The Ticker

Because the buyer effectively acquires the economic interest from the locked-box date but does not take legal ownership until closing, the buyer is implicitly paying for a period during which the seller retains legal control. To compensate the buyer for this delay, the locked-box price often includes a daily accrual — known as a “ticker” or “value accrual” — that increases the effective purchase price from the locked-box date to closing.

The ticker is typically calculated as a daily interest rate applied to the equity price, reflecting the buyer’s cost of capital or an agreed proxy. In a market with higher interest rates, the ticker becomes a more significant component of total consideration.

Locked Box vs. Completion Accounts

The locked box and completion accounts represent fundamentally different approaches to the same problem — how to set a fair price when there is a time gap between agreeing terms and closing a transaction.

Aspect	Locked Box	Completion Accounts
Price certainty	Fixed at signing	Adjusted post-closing
Reference date	Historical (locked-box date)	Completion date
Post-closing disputes	Limited to leakage claims	Common (working capital, net debt)
Seller’s preference	Generally preferred (certainty)	May accept if completion gap is short
Buyer’s preference	Acceptable if locked-box accounts are reliable	Generally preferred (pays for actuals)
Value leakage risk	Managed through prohibited leakage covenants	Not applicable (price adjusts to actuals)
Prevalent in	Europe, Asia Pacific, PE exits	North America, complex carve-outs

Neither mechanism is inherently superior. The choice depends on the quality and recency of the locked-box accounts, the expected length of the signing-to-closing period, the relative bargaining power of the parties, and market convention.

Locked Box in Practice

Leakage Protections

The integrity of the locked-box mechanism depends entirely on the effectiveness of the leakage protections. The SPA must comprehensively define what constitutes prohibited leakage:

• Dividends or distributions to shareholders (beyond permitted amounts)
• Management fees, advisory fees, or similar payments to the seller or related parties
• Repayment of shareholder loans or intercompany balances
• Asset transfers at below market value
• Assumption of liabilities on behalf of the seller
• Guarantee fees or similar payments
• Any other transfer of value from the target to the seller or its affiliates

Permitted leakage — items the parties agree upfront are acceptable — is exhaustively listed in the SPA. Anything not expressly permitted is prohibited.

Due Diligence Implications

The locked-box mechanism shifts due diligence emphasis. Because the price will not be adjusted post-closing, the buyer must be confident in the locked-box accounts before signing. This means:

• Thorough financial due diligence on the locked-box balance sheet — more intensive than in a completion accounts deal
• Review of the period between locked-box date and signing — the buyer must understand what has happened in the business since the locked-box date
• Detailed leakage analysis — identifying all payments and transfers since the locked-box date to ensure none constitute leakage

APAC Context

The locked-box mechanism has gained significant traction in Asia Pacific M&A over the past decade, particularly in private equity exits and cross-border transactions. In Australia, locked-box structures are now common in competitive auction processes, where sellers use the mechanism to maximise price certainty and simplify the post-signing process. Australian practitioners are well-versed in locked-box drafting, and the mechanism aligns well with the Australian legal framework.

In Southeast Asia, locked-box adoption varies by market maturity, as explored in our analysis of cross-border M&A in Asia. Singaporean transactions regularly employ locked-box pricing, while markets such as Indonesia and the Philippines — where accounting infrastructure may be less developed — sometimes present challenges in producing locked-box accounts of sufficient quality and recency. For targets with subsidiaries across multiple APAC jurisdictions, the locked-box analysis must consider local accounting standards, currency translation, and differing financial reporting cycles.

Japanese domestic transactions less commonly use locked-box mechanisms, though cross-border deals involving Japanese targets increasingly adopt the structure when marketed by international advisors running a sell-side M&A process. AI-powered deal platforms like Amafi help advisors evaluate pricing mechanism suitability and model locked-box scenarios across the region’s diverse markets.

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