Lafarge-Shui On Ltd. plans to raise its stake in Sichuan Shuangma Cement Co to 80% in a deal worth CNY2.8 billion ($409 million), the deal’s underwriter said Friday.

Lafarge-Shui On, a joint venture between Lafarge SA (LFRGY) and Shui On Construction & Materials Ltd. (0983.HK),  is currently the largest shareholder of the Chinese cement maker with a 57% stake.

Sichuan Shuangma will issue an additional 368 million shares to Lafarge-Shui On at CNY7.61 each, said China Euro Securities Ltd., a joint venture between CLSA and Fortune Securities Co.

In return, Lafarge-Shui On will inject its 50% interest in Dujiangyan Cement Ltd. into Sichuan Shuangma,  China Euro Securities said.

The deal is subject to Chinese regulatory approval.