Keita is an expert in economic analysis with regard to regulation and litigation matters such as antitrust, transfer pricing, and economic damages cases. He has more than 12 years' experience as a professional economist with involvement in many merger cases in various industries, among other regulation and litigation cases. Keita also has experience in cross-border cases in which he served as economist for Japanese companies. As an economic consultant, he conducted economic analyses for private companies to identify crucial evidence in support of clients' claims. From April 2012 to March 2014, he led the economic analysis team of the merger division of the Japanese Fair Trade Commission, where he reviewed the merger submissions and conducted economic analyses in major merger cases as chief investigator.