China's state-owned Beijing Enterprises Group (BJEG) has raised its stake in bid target China Gas Holdings Ltd to about 18 percent, the Hong Kong securities regulator said on Thursday.

BJEG, the parent of utility Beijing Enterprises Holding Ltd , has been consistently building its stake in China Gas, which has rebuffed a $2.2 billion joint takeover offer from ENN Energy Ltd and Sinopec.

BJEG acquired the shares from the open market on Wednesday, paying between HK$3.68 and HK$4.00 a share and well above the HK$3.50 offered by the ENN-Sinopec consortium.