Quote from h hubbins:
some exchanges have paid for exclusive trading rights for certain products. this is likely to end as the exclusive contracts expire.
Quote from xflat2186:
The Exchange didnât pay for the SPX they developed the product them selves and the deal with Standard & Poorâs is not subject to ending. There have been many law suits trying to break the proprietary listing but they have been unsuccessful. There are many other products which are proprietary products of other exchanges too, things like the SOX index and the OSX index.