It's been a wild decade for exchange-traded funds.
From the ETF industry raking in a record $4 trillion in assets, to the rise of ESG (environmental, social and governance) investing, to the SEC's approval of nontransparent ETFs, the last 10 years have brought newfound growth and areas of focus to ETF investors in the United States and around the world.
Here are some ETFs that industry leaders believe defined the decade, based on interviews on CNBC's "ETF Edge" this month.
"U.S. investors tend to be very U.S.-centric, but IEFA ... gives you exposure to Europe, to Japan, developed countries around the world, for 7 basis points," Todd Rosenbluth, senior director of ETF and mutual fund research at CFRA, said on Dec. 16.
IEFA's price tag is notably low relative to other broad-based funds. For comparison, the SPDR S&P 500 ETF Trust (SPY) costs just over 9 basis points to own.
Rosenbluth's pick has gained 37% since its 2012 launch, and has notched a roughly 19% gain so far in 2019. With nearly $74 billion in assets under management as of Dec. 26, IEFA counts the stocks of Nestle, Roche, Novartis and Toyota among its top holdings.
The inclusion of "blue-chip" companies like Nestle and Toyota in the fund has also helped investors broaden their overseas holdings on the cheap, Rosenbluth said.
"Having a low-cost, well-diversified product tied to a benchmark they know has made it easier for them to get the benefits of that diversification," he said. "It's taking share from other products from iShares and Vanguard. It's really helped asset allocation approaches in the ETF wrapper."
Main Management founding partner and CEO Kim Arthur's pick for the best ETF of the past decade — VTI, Vanguard's passively managed, diversified ETF that mirrors the broad market with more than 3,000 large-, medium- and small-cap stocks — was a bit less selective.
"It's a total U.S. market exposure," Arthur said in the Dec. 16 interview. "It's got slightly lower median market cap than the S&P, so, you're getting a size component to it."
VTI has climbed nearly 192% since the start of 2010, narrowly beating the SPY's 190% gain over the same time frame. The fund, which has a nearly 29% gain so far in 2019, has its biggest positions in the stocks of Microsoft, Apple, Alphabet, Amazon and Facebook.
"I'm going to match Todd and raise him because the expense ratio [for VTI] is 3 basis points," Arthur said. "So, investors have been able to beat the S&P 500 for 3 basis points."
A nod to the late Jack Bogle, the legendary founder of the Vanguard Group who created the world's first indexed mutual fund, Arthur's pick has proven itself for even longer than the past decade, he said.
"I'm a firm believer that Jack Bogle did more to democratize for the average investor with exposure to indexes like this," Arthur said. "If you go century to date, almost the past 20 years, it's beaten the S&P by 50 basis points a year. That's significant."
Jay Jacobs, head of research and strategy at Global X ETFs, pegged this decade's most impactful ETF as one ending the 2010s on a particularly strong note: technology.
Tracked by the XLK, which has run 301% since the start of 2010, technology has told a "performance story" for the last 10 years, outperforming the S&P while fundamentally altering how investors and consumers ate, shopped and were entertained, Jacobs said.
"Think about the impact that technology has [had] over the last 10 years. We didn't have mobile social media. We didn't have mobile e-commerce," Jacobs told "ETF Edge" on Dec. 18. "So many new technologies have come out and that, I think, is really reflected in the excitement around technology stocks."
The impact was so meaningful, Jacobs said, that oftentimes, technology stocks made "the difference between an outperforming portfolio and an underperforming portfolio" for both retail investors and professionals.
"You saw a lot of asset managers allocating towards high-growth technology stocks," he said. "We saw how important the FANGs were in contributing to the growth of the S&P 500. It made all the world of difference."
The XLK's largest holdings are Apple and Microsoft, which together account for around 39% of the portfolio.
Hedging against global risk was the decade's most impactful theme according to John Davi, founder and chief investment officer of Astoria Portfolio Advisors.
"If you look at all the ETFs that have gathered the most assets over the last 10 years, it's going to be your VTI, your SPY, your EFA, EEM, so, those are low-cost, pure-beta ETFs, like your standard wealth management solutions. So, USMV is the largest asset gatherer outside of that core, so I like it. It hedges the downside risk," Davi said in the Dec. 18 interview.
USMV has climbed more than 155% since the start of 2010, drawing in over $37 billion in assets as of Dec. 26. To Davi, the fund has proved a strong alternative to broad-market funds, falling only 8% in 2018's fourth-quarter collapse compared with the S&P's 14% drop.
"You just don't have as much downside risk as the S&P," Davi said. "Over the last 10 years, it's had better risk-adjusted returns [than the] rest of the S&P, and so it has some built-in protection."
Brendan Ahern, chief investment officer of China-focused ETF issuer KraneShares, said in the Dec. 18 interview that "for the past decade, there's been one game in town": U.S.-based large-cap stocks.
"The more you've diversified, the worse you've done, so, certainly for the past decade, anything but the S&P 500 has led to lagging, outside of breaking out, say, tech, because we've been in this growth market," he said.