Two New York City pension funds voted to divest their portfolios of some $4 billion worth of fossil fuel company securities, Mayor Bill de Blasio, Comptroller Scott Stringer, and fund trustees said.

"Fossil fuels are not only bad for our planet and our frontline communities, they are a bad investment,” said de Blasio in a statement on Jan. 25.

New York was among a dozen big cities worldwide that pledged to shift their money out of the fossil fuel industry last September, part of a broader rush to embrace renewable energy both to slow climate change for cost reasons.

The move is partly symbolic, affecting just a piece of the $240 billion in pension assets managed by Stringer's office. Officials will not identify securities to be sold until transactions are completed.

The two funds that voted to divest represent city teachers and other workers with a combined $168 billion under management. Two smaller funds for the city's police and firefighters, with a combined $63 billion, have not voted to divest. A fifth fund with $8 billion is expected to vote to divest soon, the statement said.

The steps go further than actions by other big pension funds in liberal-leaning areas to date. New York State's common retirement fund leaders, for instance, last month set a goal for their investments to reflect net-zero greenhouse gas emissions by the year 2040, and called divestment "a last resort."