With day two of Amazon Prime Day underway, investors might be looking for a different kind of deal.
Enter the ProShares Online Retail ETF, ticker ONLN, an exchange-traded fund that tracks 25 of the largest e-commerce companies in the market. Amazon and Alibaba, its top two holdings, account for 25% and 12% of the ETF, respectively.
The fund has climbed nearly 28% year to date, topping the S&P 500's 20% gain. ProShares' Long Online/Short Stores ETF, another one of its funds that invests in e-commerce plays long term while short selling brick-and-mortar-focused stocks, has seen an even stronger performance, with a 31% boost just in 2019.
If you ask Simeon Hyman, ProShares' global investment strategist, the firm's approach is largely based on scale.
"No. 1, it's winner-take-all in the online space," Hyman said Monday on CNBC's "ETF Edge." "Scale is everything. No. 2, it's a lot more diversified than just playing Amazon."
While both funds have their heaviest weighting in Amazon, the online retail ETF also includes names like newly public pet product seller Chewy, while the long online/short stores ETF has an equally weighted portion with brick-and-mortar plays like Best Buy.
Both ETFs are a way to play the impending growth in online retail, which only accounts for a fraction of overall U.S. sales, Hyman said.
"Ten percent of sales are online in the U.S., about 12% globally," he said. "There is a long way to go and a lot of pain to be had on the brick-and-mortar side. We're really in the early innings."
"Even if we only get to 25[%] or 30% of online retail as a share of overall, we're only one-third of the way there," he said. "And guess what: Amazon's only one-third of the size of Walmart, so, from our perspective, it's in full swing, but really early innings."
Not everybody was sold on the longevity of this strategy. Ric Edelman, co-founder and chairman of Edelman Financial Engines and the No. 1 independent advisor in the country, according to Barron's, had his reservations about its prospects.
"I'm concerned that this is a backwards-looking idea, that because of the trend we all see with retail stores closing and with Amazon and other online retailers doing really well, there's an assumption that this trend is going to continue, translating into superior profits for the online retailers and subpar profits, even losses, for the brick and mortars," he said in the same "ETF Edge" interview.
"I'm not sure that's a winning argument over the next three to five years," Edelman said. "This is the kind of … play you should've done years ago, not now."
However, Tom Lydon, editor and proprietor of ETFTrends.com and president of Global Trends Investments, said he sees the trend progressing every day.
"When we were growing up we used to go to the mall. We don't do that anymore," Lydon said in the same segment. "Every day we have boxes showing up at our house, and if you want to get something, it's so time efficient. ... We've got a huge amount of upside."