Lockup is the working capital tied up in unbilled work in progress and unpaid debtors in a professional services business, typically expressed in days of fee revenue. Lockup is the principal working capital metric in accounting, legal, and consulting practice acquisitions, because professional services businesses generate cash only as work in progress is converted to invoices and invoices are converted to receipts.
Lockup of 90 days or less is generally considered strong for Australian accounting and legal practices; lockup above 150 days typically signals collection or billing process weakness that affects valuation.