TOKYO -- Nikkei finalized on Thursday a revision to the methodology of compiling the Nikkei 225 to address cases in which constituent companies list subsidiaries or business units through spinoffs. The change is designed to preserve index continuity during such corporate actions by temporarily including the spun-off entity in the index calculation.
Under the revised rule, the spun-off company will be added to the index calculation from the ex-rights date until its official listing on the Tokyo Stock Exchange. Because the entity does not have a market price before listing, the offering or reference price will be used to calculate the index. The company will be removed from the index calculation on the next business day after listing.
The decision follows a public consultation conducted in June and the revision takes effect immediately. It will apply to the upcoming direct listing of Sony Financial Group, which is scheduled to be spun off from Sony Group in September.
Details of the rule change are available on the official Nikkei Indexes website.
