What a share is

A share is a small slice of ownership in a company. If a company were split into a billion equal pieces, one share would be one of those pieces.

Owning one gets you three things. A claim on the profits, often paid out as dividends. A vote at the annual meeting. And a price that rises or falls as investors change their minds about what the company's future profits are worth.

Companies sell shares to raise money. The first time a company does this publicly is an IPO (initial public offering). Anthropic filed for one this week. After that, shares trade between investors on a stock exchange, and the company only sees the money from that first sale.

The price you see is simply the last price two people agreed to trade at. That is why it moves all day.

One UK quirk to learn early: London prices are usually quoted in pence, written p or GBX. SSE at 2,485p is £24.85 a share.