Note that Yahoo! Japan is separate from Yahoo. When Verizon bough Yahoo, certain patents, holdings and investments were not part of the sale and were spun off into a new business called Altaba.

The (minority) stake in Yahoo! Japan that was owned by Yahoo is now owned by Altaba. Probably the only connection between Yahoo and Yahoo! Japan is the name, which Yahoo! Japan license from Verison.

source: https://www.reuters.com/article/us-yahoo-m-a-verizon-idUSKCN...