Heirs to the Rockefeller family, which made its vast fortune from oil, are to sell investments in fossil fuels and reinvest in clean energy, reports say.
The Rockefeller Brothers Fund is joining a coalition of philanthropists pledging to rid themselves of more than $50 bn (£31 bn) in fossil fuel assets.
The announcement will be made on Monday, a day before the UN climate change summit opens on Tuesday.
Some 650 individuals and 180 institutions have joined the coalition.
It is part of a growing global initiative called Global Divest-Invest, which began on university campuses several years ago, the New York Times reports.
Pledges from pension funds, religious groups and big universities have reportedly doubled since the start of 2014.
Rockefeller Brothers Fund director Stephen Heintz said the move to divest from fossil fuels would be in line with oil tycoon John D Rockefeller’s wishes,
“We are quite convinced that if he were alive today, as an astute businessman looking out to the future, he would be moving out of fossil fuels and investing in clean, renewable energy,” Mr Heintz said in a statement.
The last major conference on climate change, in Copenhagen in 2009, ended without results
The philanthropic organisation was founded in 1940 by the sons of John D Rockefeller. As of 31 July 2014, the fund’s investment assets were worth $860 million.
“There is a moral imperative to preserve a healthy planet,” Valerie Rockefeller Wayne, a great-great-granddaughter of Mr Rockefeller and a trustee of the fund, is quoted by the Washington Post as saying.
A climate change summit is due to start on Tuesday at the UN headquarters in New York, with 125 heads of state and government members expected to attend.
It is the first such gathering since the unsuccessful climate conference in Copenhagen in 2009.
UN Secretary General Ban Ki-moon hopes leaders can make progress on a universal climate agreement to be signed by all nations at the end of 2015.
On Sunday, hundreds of thousands of marchers took to the streets in more than 2,000 locations worldwide, demanding urgent action on climate change and calling for curbs on carbon emissions.
Business leaders, environmentalists and celebrities also joined the demonstrations, which were organised by The People’s Climate March.