How Buying a Stock Actually Works

The path of an order

Investor places an order, the broker routes it, the market matches it against a willing counterparty, the trade executes at an agreed price, then it settles and the shares appear in your account.

The vocabulary you will see

These words appear on every order screen.

• Ticker: the short code identifying a listed security
• Bid: the highest price a buyer is currently offering
• Ask: the lowest price a seller is currently accepting
• Spread: the gap between bid and ask, an implicit cost
• Market order: execute promptly at the best available price, with no price limit
• Limit order: execute only at your price or better
• Fractional shares: buying part of one share by dollar amount
• Cost basis: what you paid, used later to calculate taxable gain

Market orders versus limit orders in practice

A market order prioritises execution: for actively traded stocks during market hours it usually fills almost immediately, at the best available price, which may differ from the last quote on a fast-moving day. Execution is still not certain — a trading halt, a broker rejection or a lack of liquidity can stop it — and the execution price is never guaranteed.

A limit order prioritises certainty of price: it only fills at your specified price or better, but it may not fill at all if the market never reaches it. Neither choice is universally correct; it depends on which certainty you need more.