What Is a Stock? Shares Explained in Plain English

The word "stocks" appears everywhere — in the news, in conversations, in films. But what is a stock, exactly? And why do people buy them?

The Simple Definition

A stock (also called a share) is a small piece of ownership in a company.

When a company wants to raise money, it can divide itself into millions of tiny pieces — shares — and sell them to the public. Each person who buys a share owns a small fraction of the company.

If Nike has 1.5 billion shares and you own 100 of them, you own 0.0000067% of Nike. Small, but real. You're a Nike shareholder.

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Why Companies Sell Stocks

Building a business costs money. Rather than borrowing all of it from banks (which means paying interest), companies can sell shares to investors. The investors get ownership; the company gets cash to invest in growth.

This process of selling shares to the public for the first time is called an IPO — an Initial Public Offering. After an IPO, the shares can be bought and sold freely on a stock exchange like the London Stock Exchange or the New York Stock Exchange.

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Why People Buy Stocks

Two main reasons:

Capital growth — if the company does well, its shares become more valuable. Buy at £10, sell at £25, make a profit.

Dividends — some companies share a portion of their profits with shareholders on a regular basis. These payments are called dividends. If you own shares in a company that pays dividends, you receive cash just for holding the stock.

Not all companies pay dividends. Many fast-growing companies reinvest all their profits into expansion instead.

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Stock Price: What Makes It Go Up or Down?

A stock's price reflects what people are willing to pay for it — which is driven by expectations about the company's future.

If investors believe a company will grow strongly, they'll pay more for shares. If they're worried about the future, they'll sell, and the price falls.

This is why earnings reports move stock prices so dramatically. When results beat expectations, it suggests the company is doing better than feared — so investors pay more. When results disappoint, the opposite happens.

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Common vs. Preferred Shares

Most people own common shares — the standard type that gives you voting rights and a claim on profits.

Preferred shares are different — they usually come with a fixed dividend and get paid before common shareholders if the company goes bust. But they typically don't come with voting rights.

Unless you're specifically told otherwise, when someone talks about buying stocks, they mean common shares.

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Stocks vs. Bonds

Stocks and bonds are the two main types of investments:

Stocks — ownership in a company. Higher potential returns, higher risk. If the company goes bust, shareholders can lose everything.

Bonds — loans to a company or government. The bondholder gets paid back with interest. Lower returns but more secure — bondholders get paid before shareholders if things go wrong.

Most investment portfolios contain a mix of both.

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See It in Action

Every company we cover on Ask AYO is publicly listed — meaning you can buy shares in them:

• Nike (NKE) — listed on the New York Stock Exchange. Nike's stock hit a nine-year low in early 2026, even as the underlying business showed signs of recovery.
• BYD (BYDDY) — listed in Hong Kong and Shenzhen. BYD's share price reflects investor uncertainty about whether the EV price war will destroy profits before global expansion pays off.
• H&M (HM-B.ST) — listed on the Nasdaq Stockholm. H&M's stock fell 5% on its Q1 2026 results even though profits beat expectations — because investors were focused on weak sales.

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The Bottom Line

A stock is ownership. When you buy a share, you own a tiny piece of a real business — its assets, its future profits, and its risks. Understanding what drives stock prices comes down to understanding the businesses behind them. That's what Ask AYO is for.

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Related Reading

• What Is an IPO?
• What Is a Dividend?
• Bull vs Bear Market