Fidelity Investments is building an automated portfolio-management service for individual investors, joining a growing group of money and brokers that have bought or designed robo-advisors, a spokesman for the firm said Friday.

The platform, called Fidelity Go, is being piloted internally now and will be made available next year for a small group of clients to test, according to Fidelity spokesman Robert Beauregard.

Some investors "don't have the skill, will or time to manage their money, and so they turn to a partner," said Beauregard.

Fidelity initially planned to team up with Betterment on a robo product, but has shifted gears.

Fidelity's new platform will make use of the company's own products, which include mutual funds. But the firm will also use funds managed by BlackRock, the largest manager of exchange-traded funds under its iShares brand and a business partner of Fidelity's.

When using non-Fidelity products, Fidelity Go managers will "initially select among ETFs advised by BlackRock, including iShares ETFs," according to a regulatory filing.

BlackRock, the world's largest money manager with $4.5 trillion under management, announced it would acquire the automated platform FutureAdvisor in August. Charles Schwab Corp launched its own offering, Intelligent Portfolios, in March.

The New York Times first reported the story about Fidelity's automated service. Fidelity, based in Boston, manages $2.1 trillion in assets and holds trillions more through businesses that include retail brokerage, retirement services and support for financial advice firms.