If a bearer bond has matured, you can mail it to the issuer for payment of the value plus any outstanding interest. If an interest payment is due, you can usually clip and send in a paper coupon attached to the bond to receive your interest payment. If a bearer bond is old and issued by a company that no longer exists, you likely won't be able to cash it in directly, but it could be worth having the document appraised as an antique.
To cash in your bearer bonds you'll need to mail them to the issuer.
A bond is effectively a loan to the company or government agency that issued it because it gets paid back with interest over time. You can buy and sell them, and whoever owns a bond gets the right to collect interest and ultimately principal as it comes due, or matures.
At one time, most bonds were issued as bearer bonds, meaning that whoever owned a physical certificate representing the bond could collect payments on it. Usually they'd do this by physically clipping and mailing in coupons for each interest payment, similar to the parts of paper invoices that you mail in with a check if you pay your bills by mail.
Bearer bonds have largely fallen out of favor, and nowadays most new bonds in the United States are what's called "registered bonds," meaning that data on who owns them is registered in a database. To buy and sell them, you can work with your bank or brokerage. You'll likely automatically receive interest and maturity payments on them as they're due.
Mailing Them In
If you do have any bearer bonds, you'll likely need to continue to mail in those coupons to receive interest. Since many bonds have long lifetimes – Yale University owns one that's hundreds of years old and still pays interest – and bearer bonds are still issued in some countries outside the United States, there are still plenty around. When the bond matures, you'll need to physically mail the bond to whoever issued it to receive payments.
If you're not sure where to send the bond or coupons, check online with whoever issued the bond or call the organization's investor relations office. If for some reason it's not clear from the bond itself when interest is due or when the bond matures, the organization may be able to give you that information over the phone.
The issuing organization might also give you instructions about how to mail the bond, as well as tax forms or other documentation you need to include. You may wish to insure the package since if the bond is lost or stolen, it can be difficult or impossible to replace the bond.
It's possible to come across old bearer bonds that no longer have any official value, such as if the company or other entity that issued it has gone bankrupt or has gone out of business.
If you come across a bond and you're not sure if it's still valid, you can contact the organization that issued it. If you can't find that organization or aren't sure who's responsible after a corporate merger, you can hire a firm that specializes in researching old stocks and bonds to investigate for you.
If the bond simply doesn't hold value anymore, you can also treat the physical document as an antique and keep it for your own collection or have it appraised for sale.