Young and potentially wealthy investors present a solid opportunity for investment advisors to expand their client base, a new study has concluded.
Released by TD Ameritrade Institutional, "Millionaires in the Making " shows that millennials who have less than $500,000 to invest but earn more than $150,000 a year are building wealth and have prospects, such as inheritance, that put them on a path toward significant wealth.
Yet they are also a segment of the population largely overlooked by financial firms.
"Advisors tend to go where the money already is," said George Tamer, managing director and head of strategic advisor relationships for TD Ameritrade Institutional.
Read MoreAdvisors court millennials
"Up until recently, [millennials] haven't had wealth," Tamer said. "It's difficult when there is business today to think about clients who aren't really ready for your services."
Millennials, also known as Generation Y, are generally defined as the 80 million Americans born in the 1980s and 1990s. While more than half of registered investment advisors' clients are older than 60, just 10 percent of them are under age 40.
The study identifies three separate groups of millennials: high-net-worth millennials, who have at least $500,000 to invest; potential high-net-worth millennials, who have less than $500,000 to invest but earn $150,000-plus; and mass-affluent millennials, who earn less than $150,000 and have less than $500,000 to invest.
Among the high-net-worth millennials, 65 percent work with an advisor. Of the mass affluent, 40 percent do. But of the potentially wealthy, just 33 percent have a financial advisor.
Some advisors already are targeting millennials as clients.
"It's a very rewarding endeavor," said Elizabeth Scheiderer, a certified financial planner and financial advisor with NCA Financial Planners. "They are just starting out, so the only mess to clean up might be student loans."
Read MoreMillennials to get shortchanged
Scheiderer, who at age 29 is a millennial herself, said that while her young clients might not have tons of money to invest, she can help them with a financial plan and immediate goals, like saving for a mortgage.
"I will have a relationship with them as they continue to grow," Scheiderer said. "They want to be high-net-worth retirees someday."
The study also showed that of the potentially wealthy, 55 percent are more likely to hire their own advisor than their wealthier peers. Sixty-three percent of high-net-worth millennials use their family's advisor and plan to stay put.
"That generation looks to parents and grandparents for advice, and they are looking for referrals," Tamer said. "That tells me that [advisors] should be focusing on children of current clients."
Scheiderer said some of her millennials are children of clients but that she also actively pursues clients beyond that.
"There are lots of motivated young professionals who want help," she said.
Douglas Boneparth, a CFP and chief operating officer of Life and Wealth Planning, also focuses on millennials.
Read MoreHow to retire by 40
"A lot of the ones I work with are going to be superstars," Boneparth said. "It's not about [their assets] today; that will come with time, but they need help today."
The study also found that potentials and mass affluents prefer advisors who are older (55 percent and 58 percent, respectively) compared with 29 percent of high-net-worth millennials.
Also, among the wealthy millennials, 38 percent prefer working with someone their own age, compared with 16 percent of the potentials and 13 percent of the mass affluent.
Nevertheless, Boneparth, who is 30, said his young clients like working with someone their own age.
"I'm no different from them," he said. "They want to be able to relate to someone who is going through what they are, and being able to relate on that emotional level is important."
The study also explored communication preferences among millennials. Across the board, the preferred method is email (69 percent) followed by phone (67 percent).
Read MoreGen Y women a financial force
High-net-worth millennials tend to like a broader mix of communication, including social media, such as Facebook and Twitter.
Scheiderer has been using social media for about six months as part of her outreach efforts.
"The idea is, you entertain, you engage and you teach," she said. "That's how you keep a social media audience."
The study says millennials expect advisors to be accessible and immediately responsive, with 85 percent wanting phone calls returned the same day.
"I always tell my clients that if I don't get back to them right away, something is wrong," Boneparth said. "There are too many easy ways to [respond]. Why wouldn't I do that?"
Some advisors say that the industry is not intentionally overlooking millennials as clients.
Read MoreGen Xers seek 'livable' lives
"I don't think we're ignoring [millennials]," said Laurie Nardone, a CFP and principal at Shira Ridge Wealth Management. "Many of us grew our businesses through referrals, and we don't have a young enough client base yet to start generating referrals."
Nardone said she hopes that changes.
"I'm hoping that the few millennials we have will talk to their friends and say, 'She's pretty cool, and she knows how to use technology,'" she said.