Tesla and SpaceX CEO would be hit heavily by the tax. PETER PARKS/AFP via Getty Images Musk would have paid $4.6 billion in 2020 under Warren's "ultra-millionaire" plan, tax groups said. The Tesla and SpaceX CEO was worth at least $150 billion at the end of 2020. Musk plans to use his fortunes to fund a future colony on Mars. Visit the Business section of Insider for more stories. Elon Musk would have paid $4.6 billion in 2020 under proposals for an "ultra-millionaire" tax, data from tax groups shows.Sen.