China's state foreign exchange investment company, still under preparation for establishment, has agreed to invest US$3 billion in US private equity firm the Blackstone Group, according to a joint news release.

Wang Jianxi, Chairman of the China Jianyin Investment Limited (China Jianyin), told Xinhua Monday that under an agreement signed on Sunday, the new state forex investment company will buy less than 10 percent non-voting stake in Blackstone.

As a state-owned investment company, China Jianyin will be merged into the state forex investment company after its establishment.

According to the joint news release from the state forex investment company and the Blackstone, the deal will be closed concurrently with Blackstone's four billion US dollars initial public offering (IPO) planned to be launched in mid June.

The Chinese investment company will buy the shares at 95.5 percent of the IPO price and hold them for at least four years.