Capital stock is the number of common and preferred shares that a company is authorized to issue, and is recorded in shareholders' equity. Capital stock, also known as authorized stock, refers to all common stock and preferred stock a corporation is legally allowed to issue.ALLEGHENY TECHNOLOGIES INCORPORATED ; Section 11. Additional information on the taxation of LLCs is available in the. Capital stock, also known as authorized stock, refers to all common stock and preferred stock a corporation is legally allowed to issue.