A Roth IRA is one of the best possible ways to invest for retirement, and in fact, many experts think it’s the single best retirement account to have. That’s because a Roth IRA allows you to grow your money tax-free for decades and then withdraw it without paying taxes in retirement, too.

But what are the best investments for your Roth IRA? You’ll want to focus on investments that have a strong likelihood of growing a lot over the long term, but with little chance of going down. That means steering clear of highly speculative investments. Here are some of the best investments for your Roth IRA and why they may work for you.

1. S&P 500 index funds

One of the best places to begin investing your Roth IRA is with a fund based on the Standard & Poor’s 500 Index. It’s a collection of hundreds of America’s top companies, including many of the names you know and use every day (Amazon, Apple and Microsoft, for example).

Over time the index has performed well, with average annual returns of about 10 percent. With this index fund, you’ll enjoy a broadly diversified portfolio that includes some of the world’s strongest companies, meaning you’ll have reduced risk and the potential for solid gains. It also doesn’t hurt that these funds often come with low expense ratios, meaning you won’t pay a lot to the fund’s managers and so more of your returns stay in your pocket.

2. Dividend stock funds

Dividend stock funds are another popular option. Companies that pay dividends tend to be in mature industries and generate a ton of cash, allowing them to distribute the money to shareholders. The best companies increase their payouts annually for decades, turning your investment into a dividend dynamo. Plus, they tend to be less volatile than an average fund.

Dividend stock funds can be particularly attractive in a Roth IRA because they are relatively safe and the fact that the dividends are not subject to tax. Investors can roll dividends right back into the dividend fund and keep the payouts growing year after year.

3. REIT funds

Real estate investment trusts (REITs) may sound fancy, but it’s just the name for a special kind of tax-advantaged company that manages real estate investments. By law, REITs must pay out most of their income as dividends in exchange for not having to pay tax at the corporate level. That tax-advantaged structure means that they’re a preferred place for real estate investors.

REIT funds are popular with investors because they pay out high dividends, and they have a strong track record of returns over time, too. Plus, inside the Roth IRA you won’t owe any taxes on those dividends, allowing you to reinvest them in more shares.

4. Target-date funds

A target-date fund is a good pick for investors who don’t want to focus on managing a portfolio. With a target-date fund, you choose the year when you want to access the money, and the fund automatically moves you from riskier, high-return assets (stocks) to safer, low-return assets (bonds) as you approach your date. Deposit money and let the fund company run the show.

The downside to target-date funds, is that they can cost more than other funds, though their expense ratio is still often reasonable. But that additional cost is for their extra management.

5. Small-cap stock funds

Funds that invest in small companies – those called small-cap stocks – are an attractive place for long-term investment returns. Small-caps have the potential to grow quickly over time, and they’re often high-growth companies, but not always. Because they’re smaller and have fewer financial resources, small caps tend to be riskier, but they can make up for it with high returns.

Because of their potential for growth over time, small-caps can be a good investment for a Roth IRA, letting you compound your money. You can invest in a fund focused exclusively on small caps, such as an index fund that tracks the Russell 2000, and enjoy the relative safety created by the fund’s well-diversified portfolio of holdings.

6. Nasdaq-100 index funds

If you believe in the continued growth of tech stocks, this kind of Nasdaq fund is a great place to invest, potentially for decades. You’ll get some diversification and may be able to compound your money at attractive rates.

A Nasdaq-100 index fund focuses on the largest names trading on the Nasdaq exchange, which is chock full of tech firms you might use every day, including Amazon, Apple and Meta Platforms (formerly known as Facebook). This kind of fund gives you high exposure to these top players, even more than you’d get in an S&P 500 index fund, supercharging your returns if these stocks do well. Of course, inside a Roth IRA you won’t pay any capital gains taxes, either on your sales or when you make a qualified withdrawal from the account.