Superficially, it should be a perfect match. Interest in cryptocurrencies has surged among the young and tech literate, exactly the same demographic targeted by the big robo-advisors.

Yet even as the finance sector starts to embrace crypto, you won’t find bitcoin or ether in model advice portfolios. The dilemma for the industry is that registered investment advisor status is the foundation of its hard-won mainstream acceptance and conveys a legal duty to act in a client’s best interests.

As robo-advising becomes more popular—Schwab predicts assets managed by robo-advisors will grow to $460 billion next year—automated choices have come under far more scrutiny. While crypto’s big returns over the past year are tempting to any investor, extreme volatility and a relatively short track record point to substantial risk.

“When you plug cryptos into standard asset allocation models, you need to have a very high positive expected return in order to justify any holdings in the portfolio due to their risk,” said Jim Angel, a professor at Georgetown University. It’s “highly debatable” whether crypto belongs in an investor’s portfolio at all, he added.

Set on the other side is the opportunity. Survey after survey shows millennials—a generation just starting to gain investable assets yet often wary of the cost of traditional advice—are most likely to believe cryptocurrency is a legitimate asset class and indeed may already be buying Bitcoin.

The average U.S. crypto investor is a 38-year-old male with a household income of $110,000, according to a Gemini survey.

“The magnitude of how popular crypto has become is making people look at the space and wondering if this isn’t a way they can differentiate their platform,” said David Goldstone, manager of research and analytics at Backend Benchmarking. “They want to get them young and grow with them as the complexity of their financial picture grows,” he said, referring to clients.

So far none of the major players include crypto in model or automated portfolios, even if a couple like Canada’s Wealthsimple allow customers to trade crypto on the side. Still, pretty much everyone is looking at it.

California-based WealthFront, which has about $16 billion in discretionarily managed assets according to an estimate from Backend Benchmarking, is in the early stages of a exploring a crypto offering that would likely include the ability to invest in bitcoin and ether, spokesperson Elly Stolnitz said. It’s too early to disclose specifics or timings, she said.

Right now, WealthFront customers are asked about risk-tolerance levels with portfolios built based on their responses. If someone changes their investment mix from the recommendation they’re shown the effects on their risk score and implications for financial goals.

“It’s in this context that we’ll show clients what their investment in crypto means within their portfolio as a whole,” Stolnitz said. “We know that many of our clients and target audience want to put some money into cryptocurrencies and we can help them think about it the right way.”

Rival New York-based Betterment with about $29 billion in assets under management is also weighing how to offer crypto—but not anytime soon.

“Crypto is something that we are very excited about as a company, but the plans for incorporating them into Betterment’s platform aren’t on the immediate road-map,” spokesperson Danielle Shechtman said. “Right now, we’re more so exploring how we might offer crypto in a responsible way, within a guided framework. In the event that Betterment does offer crypto as an investment strategy, we’d be focused on it as an asset class to hold as a small part of the overall portfolio.”

There are a couple of small startups that do offer robo-advice within a pure crypto basket, betting in the absence of bitcoin ETF there is customer demand for a managed solution.

One is Seattle-based Makara, co-founded by quantitative cryptocurrency hedge fund manager Jesse Proudman, which launched in June. It promises “crypto investing on autopilot” and claims to be the first such offering registered as an investment advisor with the SEC.

Clients can choose from six baskets, including decentralized finance and a “blue chip” weighted offering of coins with a market value of more than $10 billion. Fees are 1% of assets under management—notably higher than the 0.25% charged by conventional robo-advisors.

“There is significant pent-up demand for the asset class that isn’t satisfied by the existing exchange infrastructure,” Proudman said in an interview. “For the vast majority of market participants, this asset class is just too confusing.”

Makara doesn’t offer standard investments like stocks or bonds or require users to disclose what proportion of their total portfolio is in crypto, leaving overall rebalancing and risk judgment to the individual.

“We do remind people that this is an extremely volatile and speculative investment and should only be a part of their complete investment program,” Proudman said.

—With assistance from Ben Bain, Suzanne Woolley and Annie Massa.

This article was provided by Bloomberg News.