It will be interesting to see how this new venture will behave in their books and if they will put it in a single category (easier to track) or if they are going to blend it in in an already existing category.
Its kinda makes sense to add thet exchange business into "financial services" category.
My first assumption would be that one as well but upon checking what their financial services encompasses[1] it doesn't feel like it would encompass the exchange - considering their nature - within that category:
It operates various businesses, including both life and non-life insurances, online banking, credit card settlement, nursing care, and venture capital.
Still, it would be nice to have it as a separate business to see how much it grows YoY, but let's see what happens in the long term...
[1]
https://en.wikipedia.org/wiki/Sony_Financial_Group