BEIJING, South Korea — China's biggest e-commerce company Alibaba Group Holding Ltd's affiliate Ant Financial Services Group has closed a $4.5 billion funding round, paving the way for a long-expected initial public offering (IPO).

China Investment Corp Capital and CCB Trust, a subsidiary of China Construction Bank Corp , participated in the Series B fundraising, Ant Financial said in a statement on Tuesday.

Ant Financial did not disclose what its valuation was after the round closed, but a person familiar with the fundraising said it is now valued at close to $60 billion.

The Alibaba affiliate's latest fundraising is the biggest ever for a private Internet company. But the company is also much older than its fundraising peers, and is only now gearing up for an IPO after 12 years and a rebranding in 2014.

Ant Financial is among a series of financial technology companies tapping investors for pre-IPO financing to fund expansion as Chinese consumers move more of their banking, payments and investing online.

The company has confirmed plans for an IPO but has previously said it does not have a timeline for the process. It did not comment on the IPO on Tuesday.

"The capital raised in Series B will allow us to invest in the infrastructure, such as cloud computing and risk control, that will underpin our long-term growth in rural and international markets," said Eric Jing, Ant Financial's president, in Tuesday's statement.

Those risk control measures include biometric verification technologies. This could help Ant Financial's private banking venture, MYbank, overcome blocks set by regulators on taking deposits, with authorities concerned about keeping transactions above-board.

Existing Ant Financial shareholders China Life Insurance Co Ltd , China Post Group, the parent of Postal Savings Bank of China, China Development Bank Capital and Primavera Capital Group also took part in the round, the online finance firm said.

Ant Financial offers services like online payment, wealth management products and insurance. Its core Alipay online payment business was founded in 2004.

The company, though, is now facing strong competition in the form of Alibaba arch-rival Tencent Holdings Ltd's WeChat Payment, which has quietly become one of the world's largest payments systems.

By Paul Carsten and Nicholas Heath; editors: Kenneth Maxwell and Muralikumar Anantharaman.