Additional paid-in capital is the aggregate amount shareholders paid for the stock in excess of par value.
As an example, let's say Widget Company issues 100 shares of stock with a $0.01 par value. The company then sells those shares for an average share price of $100, raising $10,000. In this case, the paid-in capital is $10,000, the par value is $1, and the additional paid-in capital is $9,999.
Paid-in capital is also called contributed capital. And additional paid-in capital is also known as capital in excess of par value or capital surplus.
Paid-in capital's relevance to investors
The composition of a company's capital affects its financial health, its flexibility to pursue growth initiatives, and its cost of operations. Often, capital structure analysis focuses on the company's use of debt vs. equity. But the components of equity have significance, too.
Those components are, primarily, paid-in capital and retained earnings. As noted, paid-in capital comes from shareholders. This value changes when the company issues new stock or repurchases stock from shareholders. Fluctuations in the stock's price on the secondary market do not affect the company's paid-in capital balance.