A Reuters calculation showed the stakes sold were worth at least $1 billion at the end of 2014, before the fund started big divestments from coal. The biggest holdings included a $188 million stake in CLP Holdings (>> CLP Holdings Limited).

Norway's parliament agreed last year to make the fund, built on revenues from the country's vast offshore industry, sell out of companies that derive more than 30 percent of their turnover or activity from coal.

The fund listed U.S. firms American Electric Power Co Inc (>> American Electric Power Company Inc), AES Corp (>> AES Corp) and Allete Inc (>> ALLETE Inc) among the firms, along with China Coal Energy Co Ltd (>> China Coal Energy Company Limited) and Coal India (>> Coal India Ltd), the world's biggest coal miner by output.

Global coal producer Peabody Energy Corp (>> Peabody Energy Corporation), which filed for bankruptcy on Wednesday, was also on the list. The fund expects to exclude more firms from its investment universe amid the new rule.

"The intention is to assess the remainder of relevant companies in the portfolio by the end of 2016," the fund said in a statement.

Norges Bank Investment Management said it had given the companies an opportunity to give views before they were excluded. The fund sent letters to the companies, but only five responded, it said in a statement.

The fund declined to give an overall value of its divestments so far.

The Norwegian finance ministry previously said the curtailment of investments in coal-dependent businesses could lead the fund to sell shares in about 120 companies worth some 55 billion Norwegian crowns (£4.7 billion)..

Martin Norman, climate and energy adviser at environmental group Greenpeace, welcomed the sales which he said were probably the biggest single divestment from coal ever.

"They are setting a new standard when it comes to transparency," he said. Greenpeace studies have indicated that the fund should sell shares totalling about 80 billion crowns to follow parliament's instructions to limit exposure to coal.

He said Greenpeace wanted the fund to diversify even further from fossil fuels and that it was wrong to focus only on the climate risks of coal while promoting oil and gas.

The fund has a range of ethics criteria for excluding firms from its portfolio, including severe environmental damage, nuclear weapons making, tobacco production and certain labour conditions.

(Reporting by Terje Solsvik, Stine Jacobsen and Alister Doyle; Editing by Mark Heinrich)

By Stine Jacobsen