It's an interesting thought, though. Effectively, assuming that the index were restricted to employees of member companies, setting up such a system would be tantamount to a corporate merger. In the event, if the failure of one member caused its employees to become ineligible to participate and thus autosell their shares, it could have a domino effect on other members. And if an outsider could hold shares in such an index, well, it's not really employee-owned anymore.