REUTERS/Lucy Nicholson is a popular investing app with more than 2 million users.

The app lets you trade stocks with zero broker fees, and it has recently been valued at $1.3 billion. Millennials in particular seem to love the app.

But which stocks are Robinhood users picking?

The team at Robinhood crunched the numbers and put together a list of the top stocks on their platform for Business Insider. The following stocks are the ones with the highest number of people investing in them in the first half of 2017 and do not take into account trading volume.

Robinhood users seem to love tech stocks, and 11 of the stocks below can be considered tech companies. Users also seem to be surprisingly good at picking stocks. The average year-to-date performance of the top 15 stocks was 11.03%, appreciably higher than the S&P 500's 7.94% return this year.

The following stocks are in reverse order, with the most popular at the bottom. Robinhood declined to provide exact numbers of people investing in each stock.