Assets are things that could increase the value of a company over time, while liabilities are debts that must be paid or goods and services obligations that must be fulfilled. Investors may wonder where common stock fits into the equation.

It's easy to see why a stock might be considered an asset: A stock's share price can increase, reflecting a rising valuation for the company. It's also easy to see why one might consider a stock a liability: Companies sometimes take on debt in order to buy back their own stock or use stock for employee compensation or acquisition deals. The fact that another class of shares known as "preferred stock" can function similarly to bonds further muddies the waters.  

So can common stock be classed as either an asset or a liability? No, common stock is neither an asset nor a liability. Common stock is an equity.

A pen and notepad and printed charts and a tablet.

Image source: Getty Images.

What makes common stock an equity?

Common stock is a type of security that represents an ownership position, or equity, in a company. When you buy a share of common stock, you are buying a part of that business. If a company were divided into 100 shares of common stock and you bought 10 shares, you would have a 10% stake in the company. If all the company's assets were converted into cash and all its liabilities were paid off, you would receive 10% of the cash generated from the sale.

Public companies need extra cash for many purposes, including upgrading production facilities, expanding into new markets, and pursuing acquisitions. One of the easiest ways to raise funding is through issuing common stock, which comes with both advantages and disadvantages compared to taking out a traditional loan.

Unlike a loan, cash generated from stock issues doesn't have to be paid back. Instead, when a company offers stock, it confers ownership of a portion of the business to the buyer. In issuing its common stock, a company is effectively selling a piece of itself. The stock purchaser gives up cash and in exchange receives a small ownership stake in the business. This ownership position is known as equity.

Preferred stock is also an equity and is the other main category of shares aside from common stock. Despite what its name might suggest, preferred stock does not come with voting rights -- but these shares have higher priority for dividend payments and cash returns in the event that a business's assets are liquidated in bankruptcy.  

Accounting for common stock issues

The way a company accounts for common stock issuances can seem complicated; however, at its most basic level, the move simply involves crediting or increasing stockholders' equity. For this exercise, it's helpful to think of stockholders' equity as what's left when a company has paid all its debts, sometimes referred to as book value.

From the company's perspective, the transaction is recorded through traditional double-entry accounting that preserves the balance in the following equation:

Assets = Liabilities + Stockholders' equity

The inflow of cash increases the cash line in the balance sheet. In other words, the company's assets rise. To balance that accounting entry out, stockholders' equity is credited by the same amount. This entry typically occurs in a line item called "paid-in capital."

If a company chooses to repurchase some of its common stock, its assets will decrease by the amount of cash it spends even as stockholders' equity falls by the same amount. The only difference in this case is that the accounting entry for the debit is called "treasury stock."