Ant Group’s late-summer IPO filing drove home why the business — backed by 711 million active users that spent $17 trillion through its platform — is headed for potentially the world’s largest stock debut. Yet investors may do well to focus on the long-term threat to its core businesses from arch rival Tencent Holdings Ltd.

Ant is set to join the top echelon of global finance alongside Bank of America Corp., as it seeks to raise about $30 billion with a valuation of about $225 billion in Hong Kong and Shanghai, people familiar have said. Once the dust settles, the crown jewel of Jack Ma’s Alibaba Group Holding Ltd. empire has to contend with a renewed challenge from old nemesis Tencent that’s increasingly encroaching on its turf from payments to wealth management.

China’s two largest corporations Alibaba and Tencent are wrestling for online leadership in everything from social entertainment to e-commerce and cloud computing. The key to winning the war is to control the means through which a billion Chinese spend their money online. Alibaba’s 33 percent-owned Ant and Tencent’s WeChat are the smartphone and payment backbones underpinning the twin internet juggernauts.