Internet search provider Baidu Inc (BIDU - Get Report) and e-commerce company JD.com (JD - Get Report) will join other Chinese tech firms to invest $12 billion in the Shanghai-listed unit of state-owned China Unicom (CHU - Get Report) , Reuters reported.

The joint investment is part of an initiative to rejuvenate state-owned firms with private capital. Unicom is the weakest of China's state-owned telecom companies, lagging China Mobile (CHL and China Telecom (CHA - Get Report) . But Unicom is one of the world's largest mobile carriers by user numbers.

Alibaba Group Holdings (BABA - Get Report) and Tencent Holdings (TCTZF said last month that they will be part of a joint $10 billion investment into Unicom's Shanghai-listed unit, China United Network Communications Ltd.

The Unicom investments will be the largest capital raising initiative in the Asia-Pacific region since insurer AIA Group's (AAIGF 2010 IPO, Reuters said.

China Unicom stock traded up premarket.

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