You can buy index funds through a brokerage account, a retirement account, or both
Index funds live inside accounts, not standalone. You choose where to open the account first, then pick which index funds to buy within it. The main routes are a brokerage account (taxable, no contribution limits, you pay taxes on gains each year) or a retirement account like a 401(k) or IRA (tax-deferred or tax-free growth, annual contribution limits, penalties for early withdrawal). Many people use both: a retirement account for long-term money and a brokerage account for anything they might need before retirement age.
The brokerage or bank you choose matters less than you might think. Most major firms offer the same index funds at the same cost. What differs is the user interface, customer service quality, and whether they charge account fees. You are not locked in — you can move money between firms, though the process takes a few weeks.
Key Takeaways
- Brokerage accounts (taxable) have no contribution limits and let you withdraw anytime, but you pay annual taxes on investment gains.
- Retirement accounts (401(k), IRA, Roth IRA) offer tax advantages but limit how much you can contribute each year and charge penalties for withdrawals before age 59½.
- Most major brokerages charge zero commission to buy index funds and offer the same funds at similar costs, so the choice between them matters less than opening an account quickly.
- If your employer offers a 401(k) match, that is assistance programs — prioritize that before opening a personal brokerage account.
- You can hold index funds in multiple account types at the same time to match different time horizons and tax situations.
Brokerage accounts: no limits, but you pay taxes annually
A brokerage account is a regular investment account you open with a bank or investment firm. You can contribute as much as you want, whenever you want. You can withdraw the money anytime without penalty. The trade-off is that you pay federal income tax on any gains (profits) each year, even if you do not sell the fund.
Common brokerages that offer index funds include Fidelity, Vanguard, Charles Schwab, E-Trade, and Merrill Edge. Most charge zero commission to buy or sell index funds. Some charge small annual account fees if your balance is below a certain threshold (often $10,000 to $25,000), though many waive fees for accounts under $10,000 if you set up automatic deposits or use their mobile app.
Open a brokerage account if you are saving for something within the next five to ten years (a house down payment, a car, a sabbatical), or if you have already maxed out your retirement account contributions and want to invest more.
401(k) accounts: employer match is assistance programs
A 401(k) is a retirement account your employer offers. You contribute money from your paycheck before taxes are taken out, which lowers your taxable income that year. Your employer may match part of what you contribute — for example, matching 50 cents for every dollar you put in, up to 6% of your salary. That match is assistance programs you should not leave on the table.
In 2024, you can contribute up to $23,500 per year to a 401(k) (the limit changes annually). If you withdraw money before age 59½, you pay a 10% penalty plus income tax on the withdrawal. You must start taking withdrawals at age 73.
Most 401(k) plans offer a limited menu of index funds to choose from. You do not pick the brokerage — your employer does. If your employer offers a 401(k) with a match, contribute enough to get the full match before you open a personal brokerage account. If your employer does not offer a 401(k), move to the next section.
IRA accounts: tax-deferred or tax-free growth
An IRA (Individual Retirement Account) is a retirement account you open yourself, not through an employer. You can open one at any brokerage. There are two main types: a Traditional IRA and a Roth IRA.
With a Traditional IRA, contributions may be tax-deductible in the year you make them (depending on your income and whether you have access to a 401(k)). The money grows tax-deferred, meaning you do not pay taxes on gains until you withdraw it in retirement. You must start taking withdrawals at age 73, and withdrawals are taxed as income.
With a Roth IRA, contributions are made with after-tax money (you do not get a tax deduction). The money grows tax-free, and withdrawals in retirement are tax-free. You can withdraw your contributions (not the gains) anytime without penalty. There is no required withdrawal age. Roth IRAs have income limits — if you earn above a certain threshold, you cannot contribute directly (though you can use a backdoor Roth strategy, which is more complex).
In 2024, you can contribute up to $7,000 per year to an IRA (or $8,000 if you are 50 or older). You can have both a Traditional and a Roth IRA, but your combined contributions cannot exceed the annual limit. Open an IRA if you do not have access to a 401(k), or if you have already maxed out your 401(k) and want to save more for retirement.
Comparing account types side by side
| Account Type | Annual Contribution Limit (2024) | Tax Treatment | Withdrawal Rules | Best For |
|---|---|---|---|---|
| Brokerage | None | Pay taxes on gains each year | Withdraw anytime, no penalty | Short-term goals, money you might need before retirement |
| 401(k) | $23,500 | Tax-deferred (pay taxes on withdrawal) | Penalty before age 59½; required withdrawals at 73 | Employer match, long-term retirement savings |
| Traditional IRA | $7,000 | Tax-deferred (may deduct contributions) | Penalty before age 59½; required withdrawals at 73 | Self-employed, no 401(k) access, long-term savings |
| Roth IRA | $7,000 | Tax-free (contributions not deductible) | Withdraw contributions anytime; gains after 59½ | Younger investors, those expecting higher future income, tax-free growth |
How to choose a brokerage if you are opening a personal account
If you are opening a brokerage account or an IRA, you need to pick a firm. The differences between major brokerages are small. All of them offer low-cost index funds, zero-commission trading, and mobile apps. Here is what actually varies: user interface design, phone support availability, minimum account balance, and whether they charge annual fees.
Vanguard is known for low costs and investor-friendly policies (it is owned by its clients). Fidelity offers excellent customer service and a strong mobile app. Charles Schwab has a clean interface and good educational resources. E-Trade and Merrill Edge are solid middle-ground options. For most people, the choice between them matters far less than actually opening an account and starting to invest.
Open an account at whichever firm appeals to you. You can transfer money to a different brokerage later if you change your mind — the process takes about a week and is free at most firms.
The order to prioritize if you have multiple options
If you are starting from scratch and have choices, here is the order that makes the most financial sense:
- If your employer offers a 401(k) with a match, contribute enough to get the full match. This is assistance programs.
- If you do not have a 401(k) or have maxed it out, open a Roth IRA and contribute what you can. Roth growth is tax-free in retirement.
- If you have more money to invest after maxing your IRA ($7,000 per year), open a brokerage account. There are no limits.
- If you have a 401(k) but no employer match, consider whether a Roth IRA might give you better long-term tax treatment, then decide which to prioritize based on your timeline.
This order is not a rule — it is a starting point. Your situation may differ based on your age, income, and when you think you will need the money.
Frequently Asked Questions
Can I move money between account types?
You cannot move money directly from a 401(k) to a Roth IRA without tax consequences. You can roll a 401(k) into a Traditional IRA when you leave a job, which is tax-free. You can convert a Traditional IRA to a Roth IRA, but you pay income tax on the amount converted that year. You can move money from a brokerage account to an IRA only up to the annual contribution limit ($7,000 in 2024).
Do I need a lot of money to start?
Most brokerages have no minimum deposit to open an account. Many index funds have no minimum purchase amount, or a minimum of $1 to $100. Some brokerages waive account fees if you set up automatic monthly deposits of $50 or more. Start with whatever you have.
What if my employer does not offer a 401(k)?
Open a Roth IRA or Traditional IRA at a brokerage of your choice. You can contribute up to $7,000 per year (2024). If you are self-employed, you may also be able to open a SEP-IRA or Solo 401(k), which allow higher contributions.
Can I have accounts at multiple brokerages?
Yes. Many people have a 401(k) through their employer, an IRA at one brokerage, and a brokerage account at another. There is no penalty for this. It can make sense if different firms offer different features you want, though it also means managing multiple logins and statements.
What happens if I need the money before retirement?
Withdrawals from a 401(k) or Traditional IRA before age 59½ trigger a 10% penalty plus income tax. Roth IRA contributions (not gains) can be withdrawn anytime without penalty. A brokerage account has no withdrawal restrictions. If you think you might need money within five to ten years, use a brokerage account instead of a retirement account.