Indices including TOPIX (Tokyo Stock Price Index), calculated and published by Tokyo Stock Exchange, Inc. (TSE), are intellectual properties that belong to TSE. All rights to calculate, publicize, disseminate, and use the indices are reserved by TSE.
Therefore, a license is required to use TOPIX or other indices for the sale or the issuing of index-linked funds or bonds or other financial products including derivatives such as options, swaps and warrants on the OTC market.
In accordance to TSE's licensing requirements, a license is also needed to use TOPIX or other indices for disseminating, providing, showing etc. to a third party.
In cases where TOPIX or other indices are used for your own use as an indicator of the Tokyo stock market, a license is not required.