A Half Stock is a security sold with a par value that is 50% of what is considered to be the standard price. The par value refers to the face value of a bond, or in some cases, a stock. Half stock can be either common stock or preferred stock and, other than the reduced par value, acts as a regular share of stock. The term “half” refers to the fact that half the security's original nominal amount has been cut off and reduced to one-half its original value.Half stock can be either common stock or preferred stock and, other than the reduced par value, acts as a regular share of stock. A half stock has important differences from its full-price counterpart.