Castle completed a $9.2M investment round led by Index Ventures.

Castle, a Malmö, Sweden and San Francisco, USA-based startup that wants to help businesses keep their customers’ online accounts safe from fraud, announced the completion of a $9.2M capital investment round.

The backing was supported by Index Ventures, with participation from Y Combinator, First Round Capital, F-Prime Capital Partners, and a host of individual angel investors. Angel investors joining the round include Zack Urlocker, former COO at Duo Security, René Bonvanie, CMO at Palo Alto Networks, and Olivier Pomel, CEO at Datadog.

This round brings Castle’s total funding to $11.6M. Shardul Shah, partner at Index Ventures will join the board of directors following the announcement.

Castle, founded in 2015 by Johan Brissmyr and Sebastian Wallin, developed a software solution that helps prevent all manner of account takeover (ATO) efforts, whether through manual attempts or automated methods, including credential stuffing. The compay claims to provide the first zero-configuration solution for account takeover protection.

The company’s headquarters are in the U.S., with other offices in Sweden and Poland.