The Financial Conduct Authority from Britain has published a warning about the broker BigOption.
BigOption is a binary options broker that does not even mention on its website where it is based.
According to the FCA it is based in Britain. Because binary options are regulated in Britain since the beginning of this year, every broker needs a licence from the FCA.
But BigOption has no licence, it is not regulated, therefore the FCA has placed it on its blacklist.
For your trading use regulated brokers only.