The Tokyo bourse plans to require all companies listed on its prime section to publish simultaneously in English and Japanese any information that could impact investment decisions, in an effort to attract more overseas investors.
In a document presented to its reform panel on Wednesday, the Tokyo Stock Exchange said it would first make mandatory the simultaneous English publication of financial statements and other key items that require timely disclosure.
The rules will be applied to some 1,600 prime-listed companies, starting in April 2025.
"Simultaneous English disclosure of all documents in full is preferred, but it shall be sufficient to disclose in English a part or a summary of the content of the disclosure in Japanese," the TSE said in the presentation.
As of last year, 42.3% of companies on the prime section released their earnings reports in Japanese and English simultaneously, while only 28.5% published other key items in both languages at the same time.
The bourse's reform panel has cited foreign investors as saying that a lack of English disclosure is one of the reasons for staying away from Japan's stock market.
The new rules are the latest in a series of TSE reform steps to make the bourse more attractive to overseas investors, including the release this week of a list of companies that have responded to a call to disclose plans to improve capital efficiency.