The value of the fintech that moves more than $1 billion a day is soaring. Regulators on two continents are asking hard questions about it.

Amid allegations of sharing customer data with China, Australian payments startup Airwallex, now valued at $11 billion, is gunning for Stripe and Ramp.

Jack Zhang says he always feels like an outsider, but his company is charming investors despite pushing back a float and facing claims it is too close to China.