One of the best aspects of exchange-traded funds is that they give investors insight into greater market trends that they might not otherwise consider. And if an investor ends up having faith in said trend, he or she can invest in many different stocks related to it through ETFs.

But sometimes it’s not so easy to identify the best ETFs to invest in. After all, there are many different things to consider.

For example, a high-performing ETF with an over-the-top expense ratio might not turn out to be as fruitful as you think. And, depending on the fund’s structure, there might be an inordinate amount of risk that comes with the potential gains. (For that reason, I’m excluding leveraged funds from this list.)

But using ETFdb.com’s list of 100 Highest 5 Year ETF Returns, I’ve picked out a few that might be worth a look. While I’ve purposefully selected funds with the hope of diminishing too much thematic crossover, many of the top funds focus on the technology space. And while these funds have demonstrated impressive gains over the past five years, they’re not necessarily guaranteed to be the best ETFs to buy for the years ahead.

Still, there are plenty of lessons to be learned by examining top-performing ETFs. Here’s a breakdown of five of the best ETFs over the past five years.

Top-Performing ETFs to Watch: ARK Next Generation Internet ETF (ARKW)

Expense Ratio: 0.75%, or $75 annually per $10,000 invested
Five-Year Return: 193.4% (according to ETFdb’s calculations)
Year-to-Date Return: 24%

The ARK Next Generation Internet ETF (NYSEARCA:ARKW) tracks a group of stocks related to several hot tech-related topics, all of which will play a big role in the next generation of the internet.

As such, cloud infrastructure, mobile technology, e-commerce and cyber security companies — along with several other types of companies — are all included in ARKW’s holdings.

Top holdings like Tesla (NASDAQ:TSLA), Square (NYSE:SQ) and Roku (NASDAQ:ROKU) have all helped propel ARKW more than 190% higher over the past few years. And while some of these names have hit rockier roads (I’m thinking about TSLA), many of its holdings demonstrate long-lasting promise in the years ahead.

Most of its holdings are already invaluable to our current high-tech, luxurious lifestyles and many of these domestic companies will likely still be around for many years to come. As such, the ARKW ETF is certainly one to keep an eye on.

iShares PHLX Semiconductor ETF (SOXX)

Expense Ratio: 0.46%
Five-Year Return: 190.6%
Year-to-Date Return: 48%

As mentioned earlier, many of the best ETFs over the past five years are related to the tech space in some way. While it doesn’t focus on the same themes as ARKW, the iShares PHLX Semiconductor ETF (NASDAQ:SOXX) is no exception to this trend. Only, in this case, the SOXX ETF focuses specifically on what its namesake suggests: semiconductor stocks.

Of all the ETFs on this list, SOXX has had the best year-to-date performance, climbing 48% so far.

Part of this impressive performance can likely be attributed to chip stocks’ suffering in 2018 when oversupply concerns hurt the space. Since then, SOXX and its holdings have managed to recover nicely. With the support of top holdings like Qualcomm (NASDAQ:QCOM), Nvidia (NASDAQ:NVDA) and Applied Materials (NASDAQ:AMAT), SOXX has held strong in 2019.

However, despite this recovery and the impressive performance over the past five years, the longer-term case for SOXX might not be so glamorous.

According to Morgan Stanley analysts, “The biggest difference in semi fundamentals today vs. the last correction seen in 2015 is in the degree of excess that built up in the supply chain this go-round.” And things aren’t looking pretty for a long-lasting recovery, as “the oversupply picture looks even more dire than it did in 2015.”

Still, not everyone thinks the situation is as glum for chip stocks: “[S]ome in the industry argue that the chip supply cycles are different now because of a rapid rise in the building of data centers to accommodate the ever-growing cloud and its petabytes of data, as well as chips for internet-connected appliances and automobiles.”

Time will tell which theory pans out. In the meantime, those interested in chip stocks should watch the SOXX ETF closely. It’s a broad indicator of semiconductor companies’ health.

Vanguard Information Technology ETF (VGT)

Expense Ratio: 0.1%
Five-Year Return: 140.5%
Year-to-Date Return: 36%

The Vanguard Information Technology ETF (NYSEARCA:VGT) focuses on exactly what you’d expect: stocks within the information technology sector.

Its top holdings are comprised of head tech honchos like Microsoft (NASDAQ:MSFT), Intel (NASDAQ:INTC) and Visa (NYSE:V). And its sector diversification is quite varied with both Systems Software and Technology Hardware and Storage and Peripherals at the top of the heap (20.3% and 18.2%, respectively).

Essentially, the VGT ETF consists of all the big software and hardware names in tech that are leading innovations within their industries. But it isn’t limited to just the big dogs either. Its portfolio includes 325 stocks. So you can expect exposure to lesser-known names like education technology company 2U (NASDAQ:TWOU).

While it’s not the only tech ETF on the market, it’s among the best performing over the past five years. And with its intense focus on the tech space comes all the vulnerabilities and growth associated with it. Still, we shouldn’t expect VGT to lose too much steam in the years ahead. It may dip along with the greater market (as seen by its drop in December 2018). But that can be said about many other tech-related ETFs.

As long as tech stocks hold strong, so should VGT.

ARK Innovation ETF (ARKK)

Expense Ratio: 0.75%
Five-Year Return: 128.4%
Year-to-Date Return: 22%

Although the ARK Innovation ETF (NYSEARCA:ARKK) consists of some of the stocks mentioned earlier, its emphasis and allocations vary significantly.

For example, among its top holdings are Tesla (11.1%) and Square (7.1%), but 2U is also a top holding (3.7%). The reason for this is simple: ARKK focuses on companies that are producing “disruptive innovations.” Simply put, that’s “the introduction of a technologically enabled new product or service that potentially changes the way the world works.”

That leaves plenty of room for many lesser-known names to find a spot in its holdings. And it also means ARKK isn’t a tech stock ETF, unlike many names on this list. Other top holdings include biotech stocks like Illumina (NASDAQ:ILMN) and Crispr Therapeutics (NASDAQ:CRSP).

ARKK has been one of the best ETFs over the past five years because of its emphasis on companies that are on the cutting-edge of new advancements in technology that affect all facets of our lives. While such a focus undeniably presents significant risks, with that comes significant potential rewards. ARKK’s 22% YTD return demonstrates that it hasn’t slowed down too much despite a questionable market landscape this year.

And, as the innovations from the companies within this actively managed fund gain traction, it should only see more upside.

iShares U.S. Aerospace & Defense ETF (ITA)

Expense Ratio: 0.42%
Five-Year Return: 115.4%
Year-to-Date Return: 28%

The final ETF on this list — iShares U.S. Aerospace & Defense ETF (BATS:ITA) — is in a completely different sector than the others. ITA focuses on defense and aerospace stocks. And, for better or worse, perhaps it should be no surprise that this space has been highly profitable.

Interestingly, ITA’s top holding Boeing (NYSE:BA) — 20.8% allocation — has been making countless negative headlines this year. The frustration toward BA stock is primarily due to its 737 Max debacle. Two of its 737 Max planes crashed within a short period of time, killing 346 people. And while many have since lost faith in BA, the stock is still up more than 10% YTD.

Other top holdings like Lockheed Martin (NYSE:LMT) and United Technologies Corporation (NYSE:UTX) have also shot up this year, 44% and 38%, respectively. Events like the U.S.-China trade war and increased military spending by President Donald Trump’s administration have helped keep defense stocks on top in 2019.

Although trade tensions may ease this year, other global threats — both preexisting and rising — should keep ITA’s holdings relevant in the years ahead. It might be unrealistic to expect many of its holdings to replicate 2019’s gains, especially during a U.S. presidential election. However, we shouldn’t anticipate a drastic change in trajectory for this defense ETF yet.

Robert Waldo has been a web editor for InvestorPlace since 2016. As of this writing, he did not hold a position in any of the aforementioned securities.