How to open an account and buy your first index fund

To invest in an index fund, you need a brokerage account — an account with a company that buys and sells investments on your behalf. You open the account online or in person, fund it with money from your bank account, then use that money to buy shares of an index fund. The whole process usually takes a few days from start to finish.

The brokerage holds your money and your investments. When you want to buy an index fund, you log in, search for the fund by its ticker symbol (a short code like SPY or VOO), enter how many shares you want, and confirm the purchase. The money comes out of your account immediately, and you own the shares right away.

You do not need a large amount to start. Many brokerages let you open an account with as little as $1, though some funds have minimum purchases of $500 to $1,000. Some brokerages offer fractional shares, meaning you can buy a portion of one share if you do not have enough for a whole share.

Key Takeaways

  • You need a brokerage account to buy index funds; popular brokerages include Fidelity, Vanguard, Charles Schwab, and E*TRADE, and most charge no commission to buy or sell.
  • The process is: open an account, link your bank account, deposit money, search for the index fund by its ticker symbol, and place your order.
  • You can start with a small amount — many brokerages accept $1 or less, and fractional shares let you invest any dollar amount you have.
  • Index funds are held in your brokerage account and can be sold at any time during market hours, though selling at a loss means you lose money.

Choosing a brokerage

Fidelity, Vanguard, Charles Schwab, and E*TRADE are the largest brokerages for individual investors. All four allow you to buy index funds with no commission — you pay nothing to place the trade. They differ in their user interface, customer service hours, and the index funds they offer, but the core experience is nearly identical.

Fidelity and Charles Schwab offer 24/7 customer support by phone. Vanguard is known for low-cost index funds and is itself owned by its investors. E*TRADE has strong mobile apps and educational resources. If you already have a checking or savings account at a bank, that bank may offer brokerage services too — for example, Bank of America owns Merrill Edge.

Compare brokerages based on which index funds they offer, whether they charge account maintenance fees (most do not), and whether their website or app feels easy to use. You can open an account with one brokerage and move your money later if you change your mind, though there may be a small fee to transfer.

Opening your account step by step

Go to the brokerage's website and click the button to open a new account. You will provide your name, address, Social Security number, and employment information. The brokerage uses this to verify your identity and comply with tax law. The process takes about 10 minutes.

Next, link your bank account. You give the brokerage your bank's routing number and your account number — the same information you would use to set up a direct deposit. Some brokerages verify the link by depositing two small amounts into your bank account, which you then confirm. Others verify instantly.

Once your bank account is linked, you can transfer money into your brokerage account. Most transfers take one to three business days. Some brokerages offer a sweep feature that automatically moves money from your bank account to your brokerage account when you place a trade, so you do not have to wait.

Finding and buying the index fund you want

Log into your brokerage account and look for a search box or a "Buy" button. Type the ticker symbol of the index fund you want — for example, VOO for the Vanguard S&P 500 ETF, or VTSAX for the Vanguard Total Stock Market Index Fund. The search will show you the fund's current price per share and its performance over time.

Decide how many shares you want to buy, or how much money you want to spend. If the fund costs $400 per share and you have $1,000, you can buy 2 shares and have $200 left over. If your brokerage offers fractional shares, you can spend your full $1,000 and own 2.5 shares. Enter the amount and review the order before you confirm it.

Once you confirm, the trade executes immediately if the market is open (Monday through Friday, 9:30 a.m. to 4 p.m. Eastern time). If you place the order after market hours or on a weekend, it executes at the market open the next trading day. You will see the shares in your account right away, and you own them from that moment forward.

Understanding costs and fees

Most brokerages charge no commission to buy or sell an index fund. However, the index fund itself charges a fee called an expense ratio, which is a percentage of your money taken out each year to pay for managing the fund. A fund with a 0.03% expense ratio costs $3 per year for every $10,000 you invest. A fund with a 1% expense ratio costs $100 per year for the same amount.

Index funds have lower expense ratios than actively managed funds because they simply track an index rather than paying a manager to pick stocks. Vanguard, Fidelity, and Schwab all offer index funds with expense ratios below 0.10%. You do not pay the expense ratio upfront — it is deducted automatically from your fund's value each year.

Some brokerages charge account maintenance fees if your balance falls below a certain amount, though most waive this fee if you set up automatic deposits or use their mobile app. Read the fee schedule on the brokerage's website before you open an account.

What happens after you buy

Your index fund will go up and down in value as the stocks in the index go up and down. You do not have to do anything — the fund automatically rebalances itself to match the index it tracks. You can check your balance anytime by logging into your account, but most investors check only once a month or once a quarter.

You can add more money to your account and buy more shares whenever you want. Many investors set up automatic monthly transfers from their bank account to their brokerage account, then use that money to buy index funds on a regular schedule. This is called dollar-cost averaging and removes the pressure to time the market perfectly.

If you need to sell your shares, log in, find the fund, enter how many shares you want to sell, and confirm. The money from the sale goes back into your brokerage account as cash, which you can then transfer back to your bank account. Selling takes one to two business days to settle.

Tax considerations for index fund investors

When you sell an index fund for more than you paid for it, you owe capital gains tax on the profit. If you held the fund for more than one year, it is taxed as a long-term capital gain, which has a lower tax rate than ordinary income. If you held it for one year or less, it is taxed as a short-term capital gain at your regular income tax rate.

Index funds also pay dividends — small cash payments from the companies in the index. You owe tax on dividends in the year you receive them, even if you do not sell the fund. Some brokerages let you automatically reinvest dividends, meaning the cash is used to buy more shares instead of sitting in your account.

If you invest through a retirement account like a 401(k) or an IRA, you do not owe tax on gains or dividends until you withdraw the money in retirement. This is one reason retirement accounts are popular for long-term investing.

Frequently Asked Questions

Do I need a lot of money to start investing in index funds?

No. Most brokerages let you open an account with $1 or $0, and many index funds have no minimum purchase. If you want to buy a fund that costs $400 per share but only have $100, you can buy fractional shares. Start with whatever amount you can afford and add more over time.

Can I lose money investing in an index fund?

Yes. Index funds track the market, so if the market goes down, your fund goes down too. If you sell when the price is lower than what you paid, you lose money. However, if you hold the fund long enough, historical data shows the market has recovered from every downturn and reached new highs.

What is the difference between an ETF and a mutual fund index fund?

Both track an index and have low costs. ETFs trade like stocks during market hours and show real-time prices. Mutual funds are priced once per day after the market closes. For most investors, the difference does not matter — pick whichever your brokerage makes easiest to buy.

How often should I check my index fund balance?

As often as you want, but most experts suggest checking no more than once a month or once a quarter. Checking too often can lead to panic selling during market downturns. Index funds are meant for long-term investing, so focus on adding money regularly rather than watching daily changes.

Can I buy index funds through my employer's 401(k)?

Yes. Most 401(k) plans offer index fund options alongside other investments. Your employer may also match a portion of your contributions, which is assistance programs. Check with your HR department for a list of available funds and how to enroll.