Ant Financial Services Group, Chinese e-commerce giant Alibaba Group Holding's fintech affiliate, is in advanced talks to buy British currency exchange start-up WorldFirst in a deal that could be worth more than 500 million pounds ($632.5 million), Sky News reported on Monday, citing sources.

Ant Financial has been in talks with WorldFirst for several months, according to the report. It was unclear whether existing investors would retain a stake in WorldFirst, which was founded in 2004.