what is wallpaper 
wallpaper is the name given to stocks bonds and other securities that have become worthless this colloquialism saw its beginnings when stocks and bonds existed as printed physical certificates rather than digital identifying information stored on a brokerage s server the name stuck however and denotes when a stock or bond certificate or another exercisable right to securities such as stock options no longer has value due to a variety of reasons most commonly bankruptcy understanding wallpaperthe term wallpaper implies that because the certificates are worthless they may as well wallpaper your house with them this was an actual practice during the great depression that followed the stock market crash of 1929 in that era physical paper certificates represented actual ownership of shares of a company 