Overlooking the best ETFs for long-term growth can cost you dearly when the time comes to access your retirement account. IRA investors should prioritize growth (in exchange for extra volatility) because they have time horizons above 10-15 years. You'll have plenty of time to wait out bear markets and corrections along the way, so you can enjoy the benefits of more volatile stocks that should beat the market over the long term.

The following three ETFs offer diversified, yet focused, exposure to long-term global growth trends with great portfolio selection criteria. That's perfect for an IRA portfolio, and it's especially well suited for a Roth, which allows you to avoid capital gains taxation on your appreciation.

Dial labled "growth" being set to exponential

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Disruptive Technologies

The iShares Exponential Technologies ETF (XT 0.44%) gives investors an opportunity to capitalize on a wide range of high-growth tech trends. The fund holds around 200 stocks involved in cloud computing, artificial intelligence, analytics, robotics, cybersecurity, automation, Internet of Things, 3D printing, fintech, nanotech, and health tech. This ETF uses a proprietary system to weigh its holdings, with up to five different stocks in each target area. The allocation provides diversification across geographies and market capitalizations, whereas many ETFs are skewed heavily toward the performance of a small handful of large companies in developed economies.

If you buy the iShares Exponential Tech ETF, then you'll benefit from the growth of all the most prevalent cutting-edge forces over the coming decades. This fund should outpace the market over the long term as long as these trends stay intact, and it's hard to see a future where disruptive technology hasn't taken over a more prominent role in the economy. The iShares Exponential Tech ETF provides excellent liquidity, with average trading volume above $15 million, and it has a reasonable 0.47% expense ratio, considering its proprietary active management methodology and high growth potential. This is an efficient and effective way to gain exposure to the next wave of tech innovation.

Genomics

The ARK Genomic Revolution ETF (ARKG -1.96%) is a bit more niche, and it's great for forward-looking investors who are interested in the future of life sciences. The fund holds 58 stocks engaged in telehealth, branded pharmaceutical development, biotechnology, medical equipment production, software, and healthcare facility provision. The ETF is actively managed to gain broad exposure to stocks that will be catalyzed by disruptive life science fields such as CRISPR, targeted therapeutics, bioinformatics, molecular diagnostics, stem cells, and agricultural biology.

Investing in the forefront of health innovation is a no-brainer from a growth perspective, but prospective investors should be aware of some drawbacks related to the ETF. First, it carries a very high 0.75% expense ratio, which will erode gains every single year. This won't sit well with every investor, but I think that the active management within these emergent industries creates value above and beyond the cost. ARK's Genomic Revolution ETF is also highly volatile, so be prepared for steep drawdowns when the stock market hits rough patches. This shouldn't be a major issue for people planning to hold for multiple decades, which makes it better suited to your IRA than your regular brokerage account.

Emerging markets

If you're seeking alternatives to the above volatile, narrow strategies, you should consider the Vanguard FTSE Emerging Markets ETF (VWO 0.55%). The fund holds nearly 4,000 stocks spread among fast-growing emerging economies, with an especially heavy concentration in Hong Kong and Taiwan.

Emerging markets stocks have lagged U.S. equities over the past decade, but the next few years have the potential to depart from that trend. Emerging markets are demographically younger than developed markets, and they are experiencing blooming middle classes due to economic growth and rising populations. Economists forecast middle-class expenditures in developing economies to double their 2010 level by the middle of this decade. The companies serving this swelling group of consumers have strong demand catalysts, and shareholders are set to reap the benefits of those financial returns.

Currency and geopolitical risks are certainly on the table for emerging market investors, so be aware of that before diving in. Still, Vanguard Emerging Markets ETF holders enjoy high liquidity, diversification across all sectors, and a comparatively razor-thin 0.10% expense ratio. Emerging markets aren't the same slam dunk growth opportunity as disruptive tech, but these can be a great addition to an IRA to complement your other holdings.