- Robinhood co-founder Vlad Tenev tells CNBC that "I wouldn't say that we're anticipating a massive shift from stocks to cryptocurrencies."
- Just over three-fourths of Robinhood's more than 2 million users are under age 36, a category typically associated with less interest in stocks and more interest in bitcoin.
- The head of Coinbase's GDAX exchange, Adam White, also says investors should hold digital currencies but remain appropriately cautious.
For all the talk about millennials preferring bitcoin and other investments over stocks, the co-founder of popular stock trading app Robinhood expects equities to stay in favor.
"I wouldn't say that we're anticipating a massive shift from stocks to cryptocurrencies," Robinhood co-founder Vlad Tenev said. "We don't see the equities market going away anytime soon."
Stocks are at record highs, but digital currencies have run up even faster this year to their own all-time highs. Although talk of investing in digital currencies and the transformative force of blockchain has grown, many still see more conventional investments and technologies winning in the near term.
Just like the dot-com boom of the 1990s took more than a decade and a market crash to produce Facebook, analysts say, the cryptocurrency world still faces many growing pains.
Tenev's optimism on stock trading is notable, given that 78 percent of Robinhood's more than 2 million customers fall into the so-called millennial category, those ages 18 to 35.
The conventional thinking is that these younger investors are less interested in stocks than they are in bitcoin.
A Bankrate survey in July found that just 13 percent of younger investors like stocks, while real estate and cash were tied first place among millennial investors at 30 percent each. A separate poll conducted in August by LendEDU found that more than a third of U.S. investors ages 18 to 34 said they plan to invest in bitcoin.
The Bankrate survey was conducted by Princeton Survey Research Associates International over the telephone in July with 1,002 adults living in the continental U.S. The LendEDU poll was conducted online by OnePoll and surveyed 1,000 American consumers ages 18 and up in late August.
On the digital currency side, a leader at major cryptocurrency investing and trading company Coinbase said investors should still be cautious.
"Everyone should have a bit of exposure to digital currencies because [it] looks like [the] future," said Adam White, head of Coinbase's GDAX exchange. But there's "still a very real chance" some of the digital currencies fall "all the way to zero."
White also said digital currency investors should still heed two investment adages: Never invest in what you don't understand, and never invest more than you can afford to lose.
The cautionary tone echoes what some market watchers have been saying. Elliott Prechter, who writes about the Elliott Wave Theory widely followed by traders, said in July that bitcoin appears to be nearing the fifth and final wave of its latest run higher.
Bitcoin has more than quadrupled in value this year and was trading near $4,718 Monday, according to CoinDesk. Another digital currency, ethereum, has soared more than 3,000 percent to around $300.
The entire universe of cryptocurrencies has multiplied eight times in value this year to $150 billion, according to CoinMarketCap. That's still a tiny fraction of the roughly $200 trillion in gold, cash, stocks and bonds.
Nonetheless, digital currencies and the blockchain technology underlying them have increasingly become part of the discussion on Wall Street this year.
Fundstrat's Tom Lee predicts bitcoin will multiply five times more to $25,000 by 2022. He also laid out in a note on Friday how even a 2 percent allocation to digital currencies would have added about 2.29 percent to total return for a traditional portfolio with 60 percent allocation to stocks and 40 percent to bonds.
Paul Brodsky, founder of Macro Allocation, discussed cryptocurrencies in the Sept. 19 issue of his newsletter. In a phone interview with CNBC last month, Brodsky said the development of digital currencies may be enough reason for stock investors to be cautious on the growth potential of the market's high-flying technology stocks.
"We may have identified something that is the next generation that will take market share from Amazon, Facebook and Google," Brodsky said. "We'll be becoming more passive on how we allocate wealth into the markets at a time when we can maybe identify a next generation of wealth creators."
Blockchain developers, particularly those behind ethereum, believe they are creating a new, decentralized kind of internet.
The company that built its business on cutting stock trading commissions also doesn't see crypto in its immediate future, Tenev told CNBC last week. Instead, he said Robinhood's plan is to expand its stock trading business and, in five years, offer the same kinds of banking products offered by JPMorgan Chase or Bank of America.