Energy giant State Power Investment Corp signed an agreement with eight strategic investors on Monday to raise 24.2 billion yuan ($3.46 billion) from the China Beijing Equity Exchange for its subsidiary Huanghe Hydropower Development Co Ltd.

In exchange, the investors, including China Life Insurance Group Co, Industrial and Commercial Bank of China, and Agricultural Bank of China, will get a 34.97 percent stake in the subsidiary.

The fundraising is the largest among all the mixed ownership reform programs for State-owned enterprises so far, and also is the largest equity financing project in domestic energy and electricity sector, said Qian Zhimin, chairman of SPIC.

The move reflects the company's unwavering efforts to deepen mixed ownership reform and to contribute to China's commitment to build a clean, safe and efficient energy mix, he said.

Zhou Lisha, a researcher at the research division of the State-owned Assets Supervision and Administration Commission, said the transaction demonstrates win-win cooperation from the participants in mixed ownership reform based on market mechanisms.

"Clean energy development needs large amount and long-term investments, and through equity financing, SPIC's equity shares of the subsidiary are transformed into capital it needs through fair and market-based pricing," she said.

"At the same time, modern corporate management experiences from the investors are brought into the company, and once clean energy projects are on stable track, they will provide steady, lasting cash returns to investors."

The company said money raised through the transaction will be invested in several photovoltaic and wind power projects in Qinghai province with capacity totaling 4.05 million kilowatts, which is close to new clean energy capacity the subsidiary had in the past 10 years.

It will also accelerate the integration of high-quality clean energy assets in related regions and strengthen utilization of capital markets after the equity transaction, to boost its presence as a world-leading clean energy player, the company said.

Data from SPIC showed clean energy capacity accounted for 50.07 percent of its total energy capacity by the end of November, hitting 73.5 million KW. The company's solar electricity generation and clean energy capacity have topped in the world and China respectively.

It has 324 subsidiaries with mixed ownership, which have brought in 25.2 billion yuan of private capital. Through mixed-ownership, the company has built an additional 253 new energy projects, using 6.7 billion yuan of investment from the private sector.