You can buy S&P 500 index funds through a brokerage account in about 15 minutes, and most people do it online without speaking to anyone

An S&P 500 index fund tracks the 500 largest publicly traded companies in the United States. To own one, you open an account with a brokerage firm (Vanguard, Fidelity, Charles Schwab, and Merrill Edge are the largest), link a bank account, and place an order for shares. The fund itself does the work of holding all 500 stocks in the right proportions — you do not buy them individually. Most brokerages let you start with as little as $1, though some funds have a $1,000 or $3,000 minimum for the first purchase.

The actual steps are straightforward: create an account online, verify your identity (usually by uploading a driver's license), link your bank account, and search for the fund by its ticker symbol. Common S&P 500 index funds include VOO (Vanguard), FXAIX (Fidelity), and SPLG (SPDR). You enter the dollar amount you want to invest, review the order, and confirm. The shares settle in your account within one to three business days.

Key Takeaways

  • You need a brokerage account (Vanguard, Fidelity, Charles Schwab, or similar) and a linked bank account to buy S&P 500 index funds.
  • Most brokerages allow you to start with $1, though some specific funds have minimums of $1,000 to $3,000 for the first purchase.
  • The entire process — account creation, identity verification, and your first purchase — usually takes 15 to 30 minutes online.
  • You can set up automatic monthly investments (called dollar-cost averaging) so money transfers from your bank and buys shares on a schedule you choose.
  • Expense ratios on S&P 500 index funds are typically 0.03% to 0.10% per year, meaning you pay very little to own the fund.

Choosing a brokerage and opening an account

The brokerage you choose matters less than you might think, because the major firms (Vanguard, Fidelity, Charles Schwab, E-Trade, Merrill Edge, and Interactive Brokers) all offer S&P 500 index funds with low costs and no trading commissions. The real differences are in user interface, customer service availability, and whether they offer other products you might want later (like IRAs or taxable accounts). Most people start with whichever brokerage they have heard of or that a friend uses.

To open an account, go to the brokerage's website and click "Open an Account" or "get your free guide." You will provide your name, address, Social Security number, and employment status. The firm will ask whether you want a taxable brokerage account (money you invest after taxes, with no contribution limits) or a retirement account like a Roth IRA or traditional IRA (which have tax advantages but annual contribution limits and withdrawal rules). Most people starting out use a taxable account because it is simpler and has no restrictions on when you can withdraw money.

After you submit your information, the brokerage will ask you to verify your identity — usually by uploading a photo of your driver's license or passport. This takes a few minutes. Once verified, you link your bank account by providing your routing number and account number (found on a check or your bank's website). Some brokerages verify the link by depositing two small amounts into your bank account, which you then confirm; others verify instantly.

Finding and purchasing the S&P 500 index fund

Once your account is open and funded, log in and search for the S&P 500 index fund by its ticker symbol. The three most common are VOO (Vanguard S&P 500 ETF), FXAIX (Fidelity S&P 500 Index Fund), and SPLG (SPDR Portfolio S&P 500 Etf Trust). All three track the same 500 companies and have expense ratios below 0.10% per year. The choice between them matters very little — pick whichever your brokerage makes easiest to find, or whichever has the lowest expense ratio at your specific firm.

When you click on the fund, the brokerage will show you the current price per share, the fund's holdings, its expense ratio, and its performance history. You do not need to read all of this; the price and expense ratio are what matter. Enter the dollar amount you want to invest (not the number of shares — the brokerage calculates that for you). Review the order one more time and confirm. The transaction is complete immediately, though the shares will not appear in your account until the market closes that day.

If the fund has a minimum investment (some do, some do not), the brokerage will tell you before you confirm. If you do not have enough money to meet the minimum, you can either deposit more or choose a different S&P 500 fund at the same brokerage that has no minimum.

Setting up automatic investments

Most brokerages let you set up automatic monthly or weekly transfers from your bank account to your brokerage account, and then automatically buy the S&P 500 fund with that money. This is called dollar-cost averaging, and it removes the decision-making from investing — you pick an amount and a date each month, and it happens without you doing anything.

To set this up, go to your account settings and look for "Automatic Investments," "Recurring Transfers," or "Scheduled Purchases." You will choose the amount, the frequency (weekly, biweekly, or monthly), and the date. The brokerage will transfer money from your bank account on that date and buy shares of the fund at whatever the price is that day. Over time, this means you buy more shares when the price is low and fewer when the price is high, which smooths out the effect of market swings.

You can change or cancel automatic investments at any time — there is no penalty. Many people start with $100 or $500 per month and increase it as their income grows.

Understanding costs and fees

S&P 500 index funds charge an expense ratio, which is an annual fee expressed as a percentage of the money you have invested. For the three most common funds (VOO, FXAIX, SPLG), this is between 0.03% and 0.10% per year. On a $10,000 investment, that is $3 to $10 per year. This fee is deducted automatically from the fund's value — you do not pay it separately.

Brokerages do not charge commissions to buy or sell S&P 500 index funds (they did 20 years ago, but this changed). Some brokerages charge account maintenance fees if your balance falls below a certain level (often $2,500 or $10,000), but most waive this fee if you set up automatic monthly investments or meet other conditions. Check your brokerage's fee schedule before you open an account if you are starting with a small amount.

If you buy and sell the same fund many times in a short period, you may trigger short-term capital gains taxes when you sell at a profit. This is a tax issue, not a brokerage fee, but it is worth knowing: holding the fund for at least a year before selling means any profit is taxed at the lower long-term capital gains rate. Most people buy S&P 500 index funds and hold them for years or decades, so this is rarely a problem.

What happens after you buy

Once you own shares of an S&P 500 index fund, you do not have to do anything. The fund automatically holds all 500 stocks and rebalances itself to stay aligned with the index. You will see the value of your shares go up and down with the stock market — sometimes by a lot in a single day. This is normal and expected. Most financial advisors recommend not checking your balance more than once or twice a year, because watching daily swings can tempt you to sell at the wrong time.

The fund pays dividends (small cash payments from the companies it holds) several times a year. Your brokerage will automatically reinvest these dividends into more shares of the fund unless you change your settings. Reinvesting is usually the right choice for long-term investors because it compounds your returns over time.

You can sell your shares at any time by logging into your account, selecting the fund, and clicking "Sell." The money will be back in your brokerage account within one to three business days, and you can then transfer it to your bank account. There is no penalty for selling, but remember that selling at a loss means you cannot use that loss to offset other gains (with some exceptions), and selling at a gain triggers capital gains taxes.

Tax considerations for different account types

If you opened a taxable brokerage account, you will owe taxes on any dividends the fund pays and on any gains when you sell. Your brokerage will send you a tax form (1099-DIV or 1099-B) each January showing what you owe. S&P 500 index funds are relatively tax-efficient because they do not trade their holdings often, so you will owe less in taxes than you would with an actively managed fund.

If you opened a Roth IRA, you do not owe taxes on dividends or gains as long as the money stays in the account. You can withdraw contributions (the money you put in) at any time without penalty, but you cannot withdraw gains until age 59½ without a 10% penalty. A traditional IRA works differently: you get a tax deduction for contributions now, but you owe taxes on everything you withdraw later.

If you are unsure which account type is right for you, start with a taxable account. It is simpler, has no restrictions, and you can always open an IRA later.

Frequently Asked Questions

Can I buy an S&P 500 index fund through my employer's 401(k)?

Many employers offer S&P 500 index funds as an option in their 401(k) plans. If your employer matches contributions, you should prioritize putting money into the 401(k) first to capture the match — it is assistance programs. After that, you can open a personal brokerage account and buy index funds there. Check your 401(k) plan documents or ask your HR department what S&P 500 options are available.

What is the difference between an ETF and a mutual fund version of the S&P 500?

VOO and SPLG are ETFs (exchange-traded funds); FXAIX is a mutual fund. Both track the same index and have nearly identical expense ratios. The main difference is that ETFs trade throughout the day like stocks, while mutual funds trade once per day after the market closes. For most people buying and holding, this difference does not matter. Pick whichever your brokerage makes easiest to buy.

Do I need a lot of money to start investing in an S&P 500 index fund?

No. Most brokerages allow you to start with $1, and automatic monthly investments of $50 or $100 are common. The key is starting early and investing consistently over time. A person who invests $100 per month for 30 years will have far more than someone who waits to invest $10,000 all at once.

What if the stock market crashes after I buy?

Market crashes are normal and happen roughly every 10 years. If you are investing for the long term (10+ years), a crash is actually good news because it means your automatic monthly investments buy more shares at lower prices. Historical data shows that the S&P 500 has recovered from every crash and reached new highs. Selling during a crash locks in losses; holding or continuing to invest lets you benefit from the recovery.

Can I lose all my money in an S&P 500 index fund?

It is theoretically possible only if all 500 of the largest U.S. companies failed at the same time, which has never happened in U.S. history. The S&P 500 is one of the most diversified investments available. You can lose money in the short term (the value can drop 20% or more in a bad year), but over 20+ year periods, the S&P 500 has always recovered and grown.