Ant Group, Alibaba's fintech arm and China's dominant mobile payments firm, on Tuesday filed for a dual listing in Hong Kong and on Shanghai's Nasdaq-style STAR Market which could raise as much as $30 billion and become the world's largest IPO ever.

Ant's initial public offering would be the first simultaneous listing in Hong Kong and the year-old STAR Market, and help both bourses boost their status as capital market centres.

Ant, already the world's most valuable unicorn - or billion-dollar unlisted tech firm - did not disclose the size, timetable or other key details of the offering in its preliminary prospectus.

Ant did not immediately respond to a request for comment on its IPO details.