Here’s the FSRankings ranking of robo-advisors based on how many accounts they manage. A single person could have multiple accounts (e.g. if you have an IRA and a college 529 savings plan), so there may be fewer actual customers for each robo-advisor.

Acorns continues to far outpace the pack. But it has a very low dollar amount per account relative to the next two robo-advisors, Betterment, and Wealthfront.

Rank Robo-Advisor Accounts
1 Screen Shot 2017-03-29 at 6.16.17 PM Acorns 1,347,000
2 betterment_logo Betterment 392,550
3 Wealthfront_Inc_Logo.svg Wealthfront 225,821
4 wisebanyan-review Wisebanyan 38,069
5 Ellevest Logo Ellevest 9,759
6 AssetBuilder Logo AssetBuilder 2,676
7 Sigfig_Logo_RGB SigFig 2,610
8 folio_logo_blue_large Hedgeable 1,956

Note: Data sourced from the companies directly and SEC filings. Not all robo-advisors listed. As of 1/29/2018. Contact FSRankings if you are a robo-advisor and would like your data updated.