This article is a part of InvestorPlace’s Best ETFs for 2018 contest. TJeff Reeves’ pick for the contest is the Vanguard FTSE All World Ex-U.S. Small Cap ETF (NYSEARCA:VSS). Emerging market exchange-traded funds were a huge story in 2017, but many investors may not have noticed. After all, the big headlines last year always seemed to be talking about President Donald Trump, or the broad-based rally in stocks or sometimes the two at the same time.

Emerging markets were, for the most part, simply not as interesting. That’s not a terrible thing, since simply owning U.S. However, we shouldn’t overlook the fact that global markets as a whole did very well — and some emerging markets ETFs did even better than domestic stock funds did. That is likely to continue on the New Year, with Goldman Sachs recently forecasting double-digit growth for the popular MSCI emerging markets index driven by a “younger and friendlier” credit cycle.

Furthermore, it seems very likely that the fast money will start moving out of U.S. After all, Dow 25,000 is a great milestone but Wall Street is defined by trend-chasing — not buying and holding forever. While I fully expect America’s economy to stay strong and the U.S. 2018 with some nice gains, it seems reasonable for investors to dabble in other places to find alpha after the great performance of the last 13 months or so. There are no shortage of index funds out there to play emerging markets, of course, including the two funds above.

However, I like the lesser-known Vanguard FTSE All World Ex-U.S. Small Cap ETF (NYSEARCA:VSS). The fund was up about 30% last year, significantly more than the S&P 500 and above a bunch of other global ETFs to boot. Here’s why I like it in 2018, too. Small Cap Bias: I’m not incredibly interested in large international plays, because multinationals in Europe and Japan aren’t much different than multinationals in the U.S. I mean, the difference between the big-picture trends behind Europe’s Unilever PLC (ADR) (NYSE:UL) and America’s Colgate-Palmolive Corporation (NYSE:CL) are pretty much the same.

The growth potential and local economics of small caps are much more interesting — and differentiated from U.S. Emerging Markets Flavor: The fund is anchored in Europe, with about 38% of the portfolio’s assets located there. However, emerging markets make up a good 20% of the portfolio as well. This is enough to make this fund a good tactical bet on emerging markets growth without taking on too much risky on these volatile regions.

Incredible Breadth: Many emerging market funds have a few hundred holdings, but the VSS ETF boasts over 3,500 components. That ensures that one dud won’t sink your performance — something that is a real risk when you play emerging markets and small caps at the same time. 10,000 invested. Not only is this inexpensive in a vacuum, it’s incredibly cheap considering you get access to thousands of small international companies that you may never be able to hold a stake in otherwise.

That’s because you simply won’t get a better way to truly diversify your portfolio than this single fund. In one Vanguard ETF, you get emerging markets PLUS developed global markets outside America PLUS small cap exposure in those markets. If you’re chasing outperformance in 2018 and truly believe in these stocks, then just buy the individual names. But if you’re looking to play ETFs and diversify, don’t bias yourself more towards domestic large caps than you already are. Instead pick VSS. It’s the perfect one-stop shop to make any portfolio truly diversified with one holding. ] or follow him on Twitter via @JeffReevesIP. As of this writing, he did not hold a position in any of the aforementioned securities.

That said, low volatility stocks outperform higher volatility peers over long holding periods and USMV has trailed the S&P 500 only slightly over the past three years, while being less volatile. Speaking of volatility, mid-caps are usually less volatile than small-caps over the long haul while producing better returns than large-caps without significantly more volatility. For long-term investors, an even better way to access mid-caps is with dividends via the WisdomTree U.S. MidCap Dividend Fund (DON). DON tracks a dividend-weighted index and has offered impressive long-term out-performance of the S&P MidCap400 Index.

DON has been one of the best performing mid-cap funds, active or passive, since its inception more than a decade ago. Small-caps are also winners over the long term, but smaller stocks are historically more volatile than their large- and mid-cap peers. Investors can ameliorate that situation by embracing a potent factor combination: small size and value.

Small-cap value stocks have historically delivered stellar long-term returns while being less volatile than smaller stocks without the value designation. The iShares S&P Small-Cap 600 Value ETF (IJS) has a three-year standard deviation of 14.24%, which is well below the comparable metric on benchmark small-cap growth indexes. Small-cap value index sector exposure often include financial services, industrials, and perhaps some consumer cyclical weight. Stock picking is a tricky endeavor, which is why many active managers fail to beat their benchmarks and why many investors have gravitated to passively managed ETFs.