A situation that arises when a target firm, in an acquisition bid (particularly, a hostile takeover), grants an option to another firm (a friendly firm) for the acquisition of an asset. The target sells to the friendly firm the assets that were perceived by the hostile bidder as the most attractive for acquisition.

An asset-lock is an arrangement between a friendly bidder and target for the sale, purchase or encumbrance of an asset in exchange for posting a bid or arranging a certain control transaction or for a period of exclusivity (to shun away potential hostile bidders) or the opportunity to conduct a due diligence for a control transaction.

It is also known as a crown jewel lock-up