By TheStreet Staff What Is Additional Paid-In Capital?Additional paid-in capital is a journal entry on the balance sheet that represents the amount investors pay for a company’s stock above par value. It is also known as the share premium, or capital surplus. When investors buy into a company’s capital stock, that capital stock is typically sold above its par value and becomes its paid-in capital. For publicly traded companies, additional paid-in capital is the difference between the shares’ par value and the amount investors pay for shares at a company’s initial public offering. This differen…