(Bloomberg) -- Betterment has surpassed $5 billion in assets under management, the first independent robo adviser to do so, as financial technology startups broaden the reach of investing services and offer lower fees than many traditional wealth managers.

The pioneer of automated investing is still a small player in the multitrillion-dollar wealth management industry but has seen substantial growth since it was founded in 2008. Assets under management were $1 billion just 18 months ago, before new clients signed up and current members added funds to their accounts, said CEO Jon Stein.

To help manage the rapid growth, Betterment is bringing in Amy Shapero in the new role of chief financial officer. Shapero has been in the fintech field for a few years but also has experience at Goldman Sachs Group and Credit Suisse.

Betterment CEO Jon Stein says he would consider adding an alert to the platfom's app to avoid client confusion if it delays trading,
Betterment CEO Jon Stein says he would consider adding an alert to the platfom's app to avoid client confusion if it delays trading,

Funds managed by robos will increase from about 0.5% of total invested assets last year to 5.6% in 2020, management consulting firm A.T. Kearney estimates. A study it did last year forecast that most of the funds that will be invested with robos aren't currently with wealth managers but are being managed by the investors themselves, with occasional guidance.

Stein and others have argued that it was never a question of robos vs. traditional wealth managers, and that the pool of funds is large enough to go around. Betterment has no minimum investment, and the average account balance is $29,000. The largest amount invested by an individual is $10 million.

Betterment's path to $5 billion hasn't always been smooth. Just a few weeks ago, the firm caught some backlash when it halted trading for customers from the start of the session at 9:30 until noon on the day after Britain's vote to exit the European Union. The main point of contention was that the firm acted without alerting its clients beforehand.

Read more: After trading halt, Betterment suffers its own Brexit shock

Stein said it was the right thing to do, and that it even boosted business. "At the height of the media interest on the day of Brexit, we had a nearly 50% increase in signups over the previous day," he said. He did say he would consider adding an alert to Betterment's app. Both clients and outside observers have wondered what robos would do in bear markets, given the lack of a personal relationship with an individual adviser.

Whenever a potential initial public offering comes up, Stein has said that going public is the future he sees for the firm, but that Betterment will first have to add more new products, such as its relatively new 401(k) offering that now has more than 150 companies signed on.

Shapero said new revenue streams will be an area of focus. Betterment raised $100 million in a new funding round this year, bringing its valuation to $700 million.