Investing behind broad market themes can be a smart way to allocate capital.

Look all around you. You'll quickly see how technological shifts are altering our economy and consumer behavior. One such area where this is strikingly clear is in the fintech sector.

The problem is that investors who want exposure to this secular trend might not know where to start in terms of finding individual stocks to buy. This is where an exchange-traded fund (ETF) comes into the picture to provide adequate exposure for your portfolio.

With that being said, here's why Ark Fintech Innovation ETF (ARKF 0.39%) might be the smartest fintech ETF that investors should buy right now with $500.

As the term fintech suggests, this is simply the combination of finance with technology. In other words, this category includes businesses that focus on integrating digital capabilities and tech innovation to better offer their users various financial services.

The Ark Fintech Innovation ETF typically holds 35 to 55 different fintech stocks. However, the top 10 positions combined make up more than 50% of the entire portfolio's assets, so there is a bit of concentration at the top here, with much smaller positions rounding things out.

I think it's a good idea that investors looking to buy this ETF understand what some of its main holdings are. The top three stocks by weight are Shopify, Coinbase, and Block. Three other notable companies in the top 10 are SoFi Technologies, Toast, and Robinhood Markets.

These six stocks give investors broad exposure to the fintech space. Shopify provides back-end tech infrastructure for online merchants, while Toast does something similar with a strict focus on restaurants and their specific needs. Coinbase, Block, SoFi, and Robinhood all offer customers, among other operations, mobile apps to handle different financial needs, like trading crypto, sending money to friends, opening a savings account, or buying stocks.

I'll also point out that the Ark Fintech Innovation ETF invests in the Ark 21Shares Bitcoin ETF, which is the fourth-largest position with a 5% weighting. A valid argument can be made that Bitcoin falls into the fintech trend. But for investors who aren't bullish on this top cryptocurrency, perhaps it's a deal-breaker when looking to buy this ETF.

Since the Ark Fintech Innovation ETF's launch in February 2019, it has climbed 52%. During that same nearly six-year stretch, the S&P 500 index has generated a total return of 132%. Clearly, the fintech ETF has been a disappointment. To make matters worse, it has taken its investors on a very volatile journey.

Here's where patience is critical for prospective investors, as the tides could be shifting for the better. In the past 12 months, it's a totally different story. The Ark Fintech Innovation ETF has soared 71%, nearly doubling the gain of the broader market index. The stronger performance more recently makes the 0.75% expense ratio seem like a good deal.

Nonetheless, it might still be difficult for some investors to want to put money to work when the ETF has surged 71% in the past 12 months. But there is still a lot of work to get back to the previous high-water mark set in February 2021. As of this writing, the Ark Fintech Innovation ETF trades 51% off its peak.

It's hard to argue with the view that this is a smart way for investors to add fintech exposure to their portfolios. The beauty of this strategy is that it does not require the time, effort, and financial or portfolio management skills that successfully picking winning individual stocks might. Viewed in this light, owning an ETF is a very low-maintenance approach. Investing $500 right now in the Ark Fintech Innovation ETF could be a good move.