Tokyo bourse overhaul spurs prime market push for Japanese cos Mount Fuji and buildings in the Shinjuku district are reflected on a table at an observation deck in Tokyo, Japan. Photographer: Kiyoshi Ota/Bloomberg July 20, 2021 Tighter requirements to stay on the Tokyo bourse’s prestigious main board are forcing Japanese companies to cease long criticised practices such as cash-hoarding and cross shareholdings, even as some investors call for tougher reform. In the biggest overhaul of Japan’s stock markets in a decade, Tokyo Stock Exchange will introduce next year tighter listing criteria for the top category, which 30% of almost 2,200 companies listed on its main section currently do not meet.