HONG KONG, May 15 (Reuters) - The listed movies unit of Alibaba Group Holding Ltd, China's biggest e-commerce company, has raised the valuation of its O2O distribution and promotions subsidiary which operates an online ticketing platform after a new round of fundraising, it said in a Hong Kong stock exchange filing released on Sunday.

Alibaba Pictures Group Ltd said that its O2O platform was now worth 13.7 billion yuan ($2.1 billion) based on the new financing raised from a group of investors led by CDH Investments, Ant Financial Services Group and Sina.com.

The statement said the O2O platform raised 1.7 billion yuan ($260 million) from the investors, who will hold approximately 12.4 per cent of its equity.

"The proceeds from this transaction will be used to sustain its operations and further strengthen its market position in a competitive and fast-developing business segment," Alibaba Pictures Chairman Shao Xiaofeng said.

(Reporting By Greg Torode; Editing by Greg Mahlich)