The Series C round was led by Holtzbrinck Ventures with participation from Velocity Capital and angel investors, Arthur Kosten, former CMO of Booking.com, and Thierry Schaap, cofounder of BinckBank.
Its equity crowdfunding campaign on Seedrs will allow its users to purchase shares in the company.
BUX, based in Amsterdam, is a community-based trading app for people with little or no experience of market trading. The app provides initial training for new users to familiarise themselves with how stocks work before they start trading real money. It has also launched an app for trading cryptocurrency.
The app operates in eight European markets, including the UK where it is regulated by Financial Conduct Authority.
The company previously raised a $6.9 million Series B round last year.