The foreign businesses, which includes Airwallex’s Chinese operations, must be substantial to sustain the company’s valuation, which is more than 120 times its Australian revenue. Other publicly listed payments companies, which offer a partial benchmark, tend to trade around 10 to 15 times revenue. Airwallex’s Australian entity recorded holding $502 million for its clients as of 31 December last year. The company makes money offering banking and money transfer services to clients, many of which are sizeable companies. Its $59 million in revenue came from $41 million in charging clients for technological developments and support services, $8 million from payment…