It's almost the time to plan for your annual IRA contribution. Technically, you do have until April to make a tax-deductible IRA contribution for tax year 2020, but you might have the cash for that contribution soon -- thanks to a year-end bonus or a generous holiday gift from Grandma. If you need some inspiration to convince you to funnel that cash windfall into your IRA, here are four growth exchange-traded funds (ETFs) that can help you reach your retirement wealth goals.

Midcap ETFs for younger savers

If retirement is more than 20 years away, you can afford to be somewhat more aggressive with your investment choices. That's assuming you can stomach some extra volatility. As long as you can hold on and enjoy the ride, exposure to smaller, younger companies gives you a shot at impressive returns.

Wooden blocks stacked up with growth spelled out on the top row.

Image source: Getty Images.

Of course, you know the usual disclosure. Historic performance is no guarantee of future results, and that's definitely the case with any aggressive growth fund. They can beat the market one quarter and fall dismally short the next. For that reason, it's best to use the following two funds as small, speculative components of your portfolio, to diversify your assets outside of the usual suspects like Apple, Amazon, and Alphabet.

First up is the Renaissance IPO ETF (NYSEMKT:IPO), which invests in larger U.S. companies that have gone public in the last two years. The fund rebalances each quarter to add new positions but will also add significant IPOs as needed between those quarterly updates. Once a company has been public for two years, it's removed from the portfolio. Current holdings include Uber, Zoom, Pinterest, Moderna, and CrowdStrike.

2020 has been a great year for public offerings, and that's reflected in this fund's performance. As of the end of September, the Renaissance IPO fund is up 68% for the year. The fund's average annual return over the last five years is 21.73%, and its expense ratio is 0.60%.

Another interesting ETF is the ARK Invest Innovation ETF (NYSEMKT:ARKK). ARK is actively managed, which means a fund manager is working hands-on to oversee the portfolio. Passively managed funds, on the other hand, either track an index or rely on rules-based trading. The distinction is important because actively managed funds tend to have higher expense ratios, and fund expenses lower your returns. ARK's expense ratio is slightly higher than Renaissance's at 0.75%.

ARK's global portfolio focuses on four types of innovation: DNA technologies, automation and manufacturing, internet infrastructure, and technologies that support financial services. Top holdings include Tesla, Invitae, Roku, Square, and Crispr Therapeutics AG.

The five-year annualized return for ARK is 39.20%, and it's grown an impressive 83.72% in 2020.

The chart below shows five-year growth for Renaissance and ARK compared to the S&P 500.

^SPX Chart

^SPX data by YCharts

Large-cap ETFs for old savers

If your targeted retirement date is within 10 or 15 years, you're wise to look for growth in larger, more established companies. The growth trajectories typically won't be as steep, but there's also less downside risk. Two funds that could fill this niche in your portfolio are Invesco QQQ (NASDAQ:QQQ) and Fidelity NASDAQ Composite Index Tracking ETF (NASDAQ:ONEQ).

QQQ is an ETF that tracks the NASDAQ 100, an index comprised of the largest nonfinancial companies listed on the NASDAQ. The index has done very well in recent years, producing a 10-year average annual return of 19.31% and year-to-date growth of 27.49%. The fund's performance is just a tick below those numbers, thanks to an efficient expense ratio of 0.20%.

The Fidelity ONEQ fund has a somewhat broader focus. This fund tracks the performance of the NASDAQ composite index, which consists of more than 2,500 companies. ONEQ takes a representative approach -- rather than duplicating the index entirely, the portfolio includes about 1,000 companies that, on a combined basis, mimic the index's performance.

ONEQ's expense ratio is 0.21%. The fund's 10-year average annual market returns are 17.12%, and it's up nearly 34% for the 12 months ending Oct. 31, 2020.

The chart below shows five-year growth for QQQ and ONEQ relative to the S&P 500. 

^SPX Chart

^SPX data by YCharts

What rises fast can fall fast

Growth ETFs can show exciting returns, but they can fall fast, too. For that reason, these funds, particularly Renaissance and ARK, aren't going to be core holdings for most investors. They're positions to hold in smaller percentages alongside more stable funds. That way, you can participate in the growth opportunity without being held hostage by the volatility. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.