The claim is that Nasdaq is going to artificially admit SpaceX to the Nasdaq-100, an index they control, in order to win their business away from NYSE. If the index you invest in is derived from the Nasdaq-100, that's problematic.
It seems kind of likely that SpaceX would make it into most of the major indices on the merits, relatively quickly (the S&P has a 1-year waiting period), just based on its likely size and liquidity.
It seems kind of likely that SpaceX would make it into most of the major indices on the merits, relatively quickly (the S&P has a 1-year waiting period), just based on its likely size and liquidity.