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US Stock Market: The Basics

How to invest in US stocks, including from outside the US: the practical steps, the costs people forget, and the risks of concentration.

AtlanticQuote editorial team. Updated 26 September 2026. How we work

Financial district street with tall skyscrapers at dusk

The essentials

  • US shares trade mainly on the NYSE and Nasdaq, from 9:30 a.m. to 4:00 p.m. New York time.
  • Non-US investors usually face currency conversion costs and withholding tax on dividends.
  • Broad US index funds spread risk across hundreds of companies.

Why US stocks come up so often

The US stock market is the largest in the world by value and home to many of the biggest global companies. That makes US shares a large part of most global index funds. It also means a portfolio can become heavily concentrated in one country, and in a handful of very large companies, without the investor realising.

Coins growing from a small plant beside a stock chart

The exchanges

US shares are listed mainly on the New York Stock Exchange and Nasdaq. Regular trading runs from 9:30 a.m. to 4:00 p.m. Eastern time on weekdays, with pre-market and after-hours sessions offered by many brokers at thinner liquidity. The exchange board shows whether they are open now.

Step by step

  1. Choose an authorised broker that offers US shares to residents of your country. See how to choose a broker.
  2. Check the account type. Tax-advantaged accounts in your country may allow US shares or funds.
  3. Complete any tax forms. Non-US investors typically complete a W-8BEN, which can reduce US withholding tax on dividends under a tax treaty.
  4. Fund the account and note how currency is converted and at what fee.
  5. Decide between shares and funds. Many investors use a US or global index fund for broad exposure.
  6. Place an order. A limit order sets the maximum price you will pay.
Tablet showing a diversified portfolio pie chart on a clean desk

Costs for non-US investors

  • FX conversion each time you buy or sell, and on dividends paid in dollars.
  • Withholding tax on dividends, commonly 30% without a treaty and often 15% with one.
  • Currency risk: your return in home currency depends on the exchange rate. See the forex guide.

Fractional shares

Some brokers let you buy a fraction of a share, so a $3,000 share can be bought with $100. Check whether fractional holdings can be transferred to another broker; often they cannot.

Concentration risk

A few very large companies make up a big share of major US indices. Holding an S&P 500 fund plus individual shares in the same big names can mean far more exposure to them than intended. See diversification.

Reader questions

Can I buy US stocks if I don't live in the US?

Yes, many brokers offer US shares to international clients. Rules differ by country, and some funds domiciled in the US may not be available to retail investors in certain regions, such as the EU, which often use equivalent European-listed ETFs instead.

What is the W-8BEN form?

A US tax form that non-US individuals submit to certify foreign status and claim any treaty rate on US-source income such as dividends.

Sources

  • New York Stock Exchange trading hours
  • Internal Revenue Service, Form W-8BEN instructions

Further reading