Britain's financial watchdog on Wednesday set diversity targets for listed companies, including that 40 per cent of boards should be women.
The Financial Conduct Authority said companies will have to make annual statements showing how they are complying with the new rules, or explain any divergences, reports Reuters.
The FCA proposed last July at least 40 per cent of board members should be women, with one senior position such as company chair, chief executive or chief financial officer held by a woman, and at least one board member from a non-white ethnic minority background.
The FCA's final rules on Wednesday made no major changes to the proposals.
The requirements will apply to financial accounting periods starting from April 1, 2022, meaning reporting would start to appear in annual reports published from early next year.
The watchdog said it would review the rules in three years' time to make sure they are working and to check if the diversity targets are still appropriate.
"As investors pay increasing attention to diversity at the top of the companies they invest in, enhancing transparency at Board and executive management level will help hold companies to account and drive further progress," said Sarah Pritchard, the FCA's executive director of markets.