Global asset managers are increasingly focused on companies' social and environmental impact.

Issues including climate risks, labour and human rights, and transparency and have become core factors in making investment decisions, the LSEG said in a statement.

"The agenda isn't being driven by politics as much, it's being led by investors, particularly long-only investors," said Mark Makepeace, Chief Executive of FTSE Russell.

Of the biggest ten asset managers, seven used ESG in their investment approach, he said.

The LSEG has sent its guidelines to more than 2,700 companies listed on its UK and Italian exchanges.

The guidelines are in line with the United Nations' Sustainable Stock Exchange Initiative, which the London exchange joined in May 2014, a forum which encourages companies to disclose information about their social and environmental impact.

European regulators have put in place legislation that will require large companies to disclose ESG issues from this year onwards.

(Reporting by Helen Reid; editing by John Stonestreet)