I am not sure it is terribly relevant. For example, I can fly on Alaska or Midway or US Airways (Shuttle) and have it count toward my tier status on American. All of the Oneworld Airlines have other partners which enable you to accrue miles but are not necessarily part of Oneworld. It's the same with the Star Alliance.

If you look at Swissair, other then their investment in Sabena (they needed a leg into the EU) the other investments are passive. i.e. They just bought one of the large catering companies.

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speedbird001