BlackRock Inc., the world's largest asset manager is acquiring a San Francisco-based robo-advisor, FutureAdvisor, the firm announced Wednesday morning.

Unlike competitors in this space, BlackRock does not plan to target individual investors with the robo-advisor, which offers portfolio management online.

Instead the firm hopes to use FutureAdvisor to enable banks, brokerage firms, insurers and 401(k) plans to use the company's digital platform to serve mass affluent investors and millennials, Frank Porcelli, head of BlackRock's U.S. wealth advisory unit, said in an interview.

Many banks and brokerage firms over the years have shifted their focus to serve higher-net-worth investors, leaving an opportunity for firms to target the "mass affluent" investors, or those with less than $1 million in investable assets, Porcelli said.

Younger investors are increasingly interested in online advice, as opposed to hiring an advisor, he said.

By using FutureAdvisor, financial institutions can either offer these clients a digital advice offering or they can use the offering to complement a broker.

Also, the FutureAdvisor platform enables clients to aggregate all of their accounts, which is often a challenge for financial advisors, said Rob Goldstein, chief operating officer and global head of BlackRock Solutions.

"You have a 401(k), then a bank account, and then maybe one or two brokerage accounts and figuring all of that out as well as the tax components is something that FutureAdvisor is strong at," Goldstein said.

Through the acquisition, FutureAdvisor will keep its brand and be part of BlackRock Solutions, the firm's risk management and technology platform.

BlackRock, which has $4.7 trillion in assets under management, has been increasingly focused on technology. The firm has been hiring to grow its "big data" team and recently hired a data scientist from Google.

Speaking at the Bernstein Strategic Decisions Conference in New York in May, BlackRock CEO Larry Fink said he believed robo-advisers were going to become an element that every major firm would need to offer.

"Everyone talks about how robo-advisers can't connect with clients," Fink said. "I actually believe those kinds of tools are like an ATM machine. We are all going to have to have it."

Terms of the acquisition, which is expected to close in the fourth quarter, were not disclosed. BlackRock said the financial impact of the transaction would not be material to the firm's earnings per share.