What actually happens when I buy a stock?

You tap "buy," and behind that button a lot happens very quickly. Your broker routes the order to an exchange or to a market-making firm, where it is matched against someone’s sell order. For a big stock this takes milliseconds. The confirmation you see is the trade being filled.

The share itself is not a paper certificate; it is an electronic record. A central depository keeps track of which broker holds how many shares, and your broker keeps track of which of its customers own them. You are the "beneficial owner," which is the legal way of saying it is yours even though it sits in the broker’s name for convenience.

Money changes hands on a slight delay. Since 2024, US trades settle one business day after the trade (T+1). In practice you can sell the share the same day if you like; the settlement timing mostly matters for when withdrawn cash becomes available.

And to be clear about one common confusion: the company does not receive your money. You bought from another investor. The company only got paid when it originally issued the shares.