At the end of 2014, Aite reported, assets for start-up digital advisors stood at $5 billion. The firm estimates those assets will swell to $15 billion by the end of this year.
Those figures don't include digitally advised assets at legacy firms such as Charles Schwab and Vanguard. Vanguard's Personal Advisor Service, which officially launched at the beginning of May after a two-year pilot, now has $17 billion in assets and charges 30 basis points for asset allocation and remote access to a financial advisor.
Schwab's newly launched Schwab Intelligent Portfolios, an allocation service for retail investors, is free.
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But it's not simply low fees and low minimums that attract younger investors, observers believe. Millennials' relationship with technology makes digital asset management more appealing, according to Nash.
Younger consumers trust technology enough to delegate important tasks.
"They're saying, 'Don't tell me I could be saving money in a cheaper ETF; put me in a cheaper ETF,'" Nash said. "There is no shortage of websites with information, but there is a shortage of services that will do it for you and take the load off your mind."