I agree with that, but it doesn't answer the question of how to account for negative wealth in a X% of americans own Y% of wealth calculation. In scenario 2, Bob has negative net wealth. In scenario 3, Bob has zero net wealth (which is why 1 and 3 are equivalent, not 2).

Supposing we had a scenario where once all accounts are settled, Alice has 2 seashells, and Bob had -1 seashells, does alice have 100% of all wealth? 200%? (Equivalently, Alice has 1, Bob has 0, and Bob owes Alice 1)

(edit for everyone else: this thread is confusing because I changed my comment to respond to founderling's edit, but founderling responded to my original comment before I changed it... ¯\_(ツ)_/¯)