They are not as easy to buy and sell as electronic stocks, and an investor might not even be able to cash them in, if for example, the company has long since closed.
Happening upon old stock certificates is actually pretty common. In the past, investors received physical certificates, referred to as in bearer form, when they bought stock. The problem of old stock certificates doesn’t arise very often anymore because most stocks are kept in electronic form in your broker’s computer system.
So, if you find an old certificate, it’s important to know where to start looking to see if your discovery is merely wallpaper from a bankrupt company or is worth cashing in on.