Flexigroup shares have surged after it announced a deal with Mastercard, which will roll out its buy now, pay later product to global banks to help them compete against the likes of Afterpay as credit card usage further tanks.

Mastercard's distribution of Flexi's bundll product, which provides a $1000 line of credit with a fast application process that puts a virtual Mastercard into a smartphone app, points to another competitive response to the wild popularity of instalment payment plans, which don't involve the same level of regulation as traditional credit cards because customers don't pay interest (but can pay fees).