It appears the report measures wealth rather than income. One can have negative wealth if the value of one's debt is greater than one's assets. A corollary is:

It appears the report measures wealth rather than income. One can have negative wealth if the value of one's debt is greater than one's assets. A corollary is: If debt is eliminated, a lot of inequality goes out the window too - since one man's debt is another's asset, and the poorest have more debt than everyone else.