"It is essential for government to provide investors with the long-term confidence they need to transform our electricity market and make investments capable of driving wider economic growth, " says the letter.

BBC: Carbon emissions target urged by business leaders

They are typically short-term investments that banks market as a high-yield alternative to bank deposit rates, which are kept low by the government.

WSJ: China Tightens Regulations on Wealth Management

In the past several years, CIC has significantly reduced its holdings of public securities and accelerated a push into longer-term investments as the fund seeks to shield itself from short-term market swings.

WSJ: China Fund Chief Says U.S. Isn't Welcoming