Lockboxes trade post-close true-ups for price certainty: you set a price as of a “lockbox date,” define permitted leakage, and close without a working-capital adjustment. That’s cleaner, but in a growing business, value after the lockbox date typically accrues to the buyer, so speed matters. We compare lockbox vs. cash-free/debt-free, translate excess working capital into headline price for apples-to-apples offers, and flag tax/escrow gotchas. Sellers get a simple checklist to protect upside and avoid leakage disputes.