Launched in 2011 by Rachleff, an investor and co-founder of Silicon Valley venture capital firm Benchmark, and Dan Caroll, Wealthfront is part of an emerging financial niche known as roboadvisors, which also includes rival Betterment. They aim to upend the core financial advising business provided by Fidelity, Charles Schwab (SCHW), and other established investment companies that have been using employees for decades to dispense advice about stocks and mutual funds.

Wealthfront’s roboadvisors analyze brokerage and 401K accounts to determine if funds are allocated wisely and whether any fees those customers are being charged are necessary. Customers can also access a comprehensive analysis of overall finances by integrating bank accounts, Fidelity investment accounts, and home value information from real estate site Redfin.

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Wealthfront, which has raised over $100 million from Spark Capital and Greylock and was last valued at $700 million in 2014, has over $3 billion in money managed as of March compared with $500 million in 2014. The startup’s service is popular among the millennial crowd, with 60% of its users under 35 years of age.

Nash—a former engineer at Apple, eBay, and LinkedIn—was named chief operating officer of the financial company in 2012 and become CEO, succeeding Rachleff, in 2014.

The company has faced increased competition over the past year as established financial institutions have started to launch their own roboadvisor services. Asset management giant BlackRock also acquired roboadvisor startup FutureAdvisor.

Rachleff didn’t share much more about why the transition was taking place except to say in a blog post that he realized that as a founder, he wanted to return to the company to help take “Wealthfront through its next chapter…to be the only financial advisor our clients will ever need.”