"Yes, billionaires will have to pay a little more," Senator Elizabeth Warren said of the revised tax package she introduced recently, "six cents on each dollar."

This modest-sounding proposal, though, would have a far-reaching impact on the wealthiest Americans when combined with her other tax plans — shrinking colossal fortunes over time and making it much more difficult to hand down multibillion-dollar legacies.

'Tax us more': Group of ultra-rich call for wealth tax
New 'wealth tax' proposed to hit richest Americans
Premium - NZ's super-rich and the tax man: 350 people. Each worth $50m plus. And