Bigcommerce moved to the US (Austin), just as almost every successful tech company (and tech individual) out of Australia ends up doing.
You can't blame Australia too much for that. It's a tiny market, and the US is an abnormally large one. It's logical.
Did they really move though? My understanding are both co-CEO's are still in Sydney. I understand they opened a major office in the US but what growing Aussie company wouldn't?
That's possible, I'm just going by what someone at the company told me. Haven't looked into it further.
I work at Bigcommerce. The development, QA, design and product teams are here in Australia; the sales, support and marketing teams are in Austin.
(There is some mixing, eg. a few devs in Austin, a few support guys here.)