The locked box mechanism fixes the price on the basis of an audited completion-date accounts and protects against leakage.
If the purchase price is to be certain already at signing, the locked box mechanism fits: the price is determined on the basis of an audited reference-date balance sheet and does not change afterwards. This gives both sides planning certainty.
The leakage protection is central. The seller is liable for ensuring that no value is extracted from the company between the reference date and closing, for example through distributions or unusual payments. We define permitted and prohibited value flows and anchor the reference-date accounts robustly in the contract.