All states require financial institutions, including brokerage firms and transfer agents, to report when personal property has been abandoned or unclaimed after a period of time specified by state law — often five years.  Before a brokerage account can be considered abandoned or unclaimed, the firm must make a diligent effort to locate the account owner.  If the firm is unable to do so, and the account has remained inactive for the period of time specified by state law, the firm must report the account to the state where the account is held.  The state then claims the account through a process called "escheatment," whereby the state becomes the owner of the account.

As part of the escheatment process, the state will hold the account as a bookkeeping entry, against which the former account owner may make a claim. The state routinely sells the securities in escheated accounts and treats the proceeds as state funds.  When a former account owner makes a valid request, however, the state will normally provide the former owner with cash equaling the value of the account at the time of escheatment.  This amount of cash does not include any dividends or interest covering the time after escheatment.

There are several websites, including commercial sites, where you can search for unclaimed property.  One non-commercial site, the National Association of Unclaimed Property Administrators, allows you to search by individual state.  The claims process is usually relatively simple so give careful consideration before agreeing to compensate anyone for handling it for you.

Each state has its own requirements for finding and claiming unclaimed property.  If you believe you have unclaimed property, the state will require you to send them information about yourself to verify your ownership of the unclaimed property.  After verifying your ownership, the state will either mail you a claim form or permit you to fill out the form online and print it for submission to the state.