ABANDONMENT
Voluntarily giving up all rights, title, or claims to property that rightfully belongs to the owner. An example of abandoned property would be stocks, bonds, or mutual funds held in a brokerage account for which the firm is unable to locate the listed owner over a specified period of time, usually a few years. If ruled to be abandoned, the property may revert to the state under the laws of Escheat. In addition to financial assets, other kinds of property that are subject to abandonment include patents, inventories, leases, trademarks, contracts, and copyrights.
cf... Everything Dictionary of Finance and Investment Terms