The guy in the video sounds Australian, but for some odd reason he says 'math' instead of 'maths'. So you're probably right... boo. Looking forward to the day when people don't stay in one place and startups begin catering to us itinerants.
BankSimple are based in Portland, Oregon (so yes, US).
So, it'd be "BankSimple is based in...", instead of "BankSimple are based in...".
When I first started reading things from the UK, I initially thought the writers simply used poor grammar :)