Common stock

Common stock is the default class of equity issued by a public company, entitling the holder to a proportional slice of profits, one vote per share on key corporate decisions, and a claim on whatever remains after creditors are paid in liquidation.

Why common stock is the default

Nearly every reference to “the stock” of a company means common stock. It is the simplest and most widely traded equity instrument, and it is what index funds and ETFs own when they track the overall market. Preferred stock and other variants exist to solve specific financing problems for the issuer; common stock is the instrument that does the job for the vast majority of use cases.

The reason is straightforward: common stock aligns the interests of shareholders with the long-term success of the firm. Because holders stand at the back of the queue in liquidation, they have a strong incentive to demand that the company invest in growth, manage risk prudently, and avoid leverage that threatens solvency. Preferred shareholders and creditors have no such incentive — they get paid regardless. Common stock therefore carries both the highest risk and (historically) the highest long-term return.

The economics of common ownership

When you own common stock, you own a proportional claim on the company’s future earnings and residual value. This is not a contract like a bond; it is an ownership stake.

The company’s board of directors decides each quarter whether to distribute any of the current profit to shareholders (as a dividend) or to retain it inside the business. If profits are retained, the hope is that reinvestment will drive even larger future profits — which eventually show up as capital gains for the shareholder. Historically, the US stock market has split the return roughly 80% capital gains and 20% dividends, but that ratio varies enormously by sector and company maturity.

One share of common stock, as a practical matter, confers almost no direct control. A retail investor with 100 shares of Apple owns 100-millionths of one percent of the company; their vote is utterly weightless. Control rests with large institutional shareholders (pension funds, index funds, mutual funds, activist hedge funds) who can mobilize concentrated voting blocs. Institutional shareholders use that power in two ways: electing the board and, occasionally, blocking or forcing major transactions like mergers, large acquisitions, or major capital allocation decisions.

Common stock in a multi-class structure

Not all companies issue a single class of common stock. To preserve control of the founder or founding family while taking the company public, many use a dual-class share structure:

• Class A shares (often the “public” class) carry one vote each and trade on an exchange.
• Class B shares (often the “founder” class) carry 10 votes each (the multiple varies) and are held by the founder or a trust. They may not trade publicly or trade only with founder consent.

This arrangement lets the founder capture the upside of a public listing (liquidity, acquisition currency) without ceding control. Companies including Alphabet, Meta, Berkshire Hathaway, and The New York Times use such structures.

The tradeoff for public shareholders is real: they have no mechanism to replace the founder, even if their judgment deteriorates. Over the very long term, this has proven unequal — some founder-led companies (Amazon, Berkshire) have outperformed the index; others have underperformed. The initial public investors bear the execution risk.

What changes a company’s common stock count

Several corporate actions change the number of shares outstanding:

• Stock splits and reverse splits multiply or divide all shares by a fixed ratio without changing the company’s value or ownership percentages. A 2-for-1 split turns 1,000 shares into 2,000 shares, each worth half as much.
• Stock dividends distribute new shares to existing shareholders in proportion to their holdings, similarly dilutive but sometimes used for tax reasons.
• Buybacks retire shares from the market, reducing the count and boosting earnings per share mechanically (though not necessarily the company’s economic value).
• Equity compensation (stock options, RSUs, restricted stock) increases the count when employees exercise options or vesting occurs.
• Secondary offerings and private placements issue new shares, diluting ownership of existing shareholders unless they buy pro-rata in a rights offering.

The most important figure to watch is the fully diluted share count, which includes all in-the-money options and unvested RSUs. A company that reports 100 million shares outstanding but has 30 million in-the-money options is actually 130 million shares diluted. Earnings per share calculations always adjust for this dilution.

Common stock versus the alternatives

Preferred stock is senior to common in both dividends and liquidation, making it less risky but also less upside-oriented. Common stock is the engine of equity returns. It is also the form of equity used in nearly all compensation arrangements for executives and employees — because the alignment is so tight between their wealth and the company’s success.

The choice to buy common stock is an accept of fundamental volatility. Over any given year or even decade, the price can fall sharply. Over the historical long run, common stock has been the most reliable wealth-builder available to retail investors, which is why index funds and asset allocation frameworks put so much emphasis on it.