The companion reports released Monday found that while Sanders's tax increases would be felt throughout the income scale, the bottom 95 percent of households would receive more in benefits than they paid in new taxes. "Households in the top 5 percent would be worse off, with the average tax increase exceeding benefit gains by about $111,000, for a net loss of 17 percent of adjusted gross income," one of the reports said.
Sanders, a Vermont senator who describes himself as a Democratic Socialist and is contending against front-runner Hillary Clinton for the Democratic presidential nomination, has proposed universal health care -- under which private insurance would be replaced by government-funded health care. That proposal alone would cost $32 trillion through 2026 -- more than twice the $15.3 trillion in revenue that Sanders's tax plans would raise by then, according to the study.
Sanders's campaign has said the universal health care plan would cost about $1.38 trillion a year -- less than half the amount projected in the reports.
Under Sanders's proposals -- which would be sure to face opposition in a Republican-controlled Congress -- all income groups would pay more tax, but most of the new revenue would come from high-income households.
Tax increases on the highest-earning Americans would generate about 25 percent of the new revenue. Sanders would tax capital gains -- a key source of wealth for the affluent -- as ordinary income and would raise marginal tax rates at the same time, taking the top rate on long-term gains and dividends to 54.2 percent from 23.8 percent.
The bottom fifth of U.S. households by income would see the largest net gain -- new benefits minus new taxes -- at more than $10,000 on average, the study said. The middle fifth would see an average net gain of $8,500.
Most of Sanders's $15.3 trillion in new taxes would come from tax increases on individuals totaling almost $13.6 trillion and from a new 6.2 percent "health care premium" payroll tax, paid by all employers. Sanders proposes a base income tax rate of 28 percent, with graduated taxes on the wealthy on top of that. The wealthiest would pay a top rate of 52 percent. He would levy an additional 2.2 percent income tax on all taxpayers.
Only $1 trillion of the $15.3 trillion revenue would come from increased taxes on corporations, which would see average U.S. tax rates increase to 37 percent from the current 35 percent, the study said.
About $429 billion would come from new excise taxes on financial transactions and carbon emissions, and $237 billion would come from higher estate and gift taxes. Sanders would expand the estate tax to cover individual estates valued at more than $3.5 million, down from $5.45 million today. And he'd impose higher graduated rates on the largest estates, up to 65 percent for individuals with estates of at least $500 million, or at least $1 billion for married couples.
Overall, Sanders' proposals "would grow federal deficits and the national debt to unprecedented levels," the study said. "A plan substantially financed by borrowing could raise interest rates and impose a substantial drag on the economy."
The Tax Policy Center is a joint venture of the Urban Institute and the Brookings Institution. It worked with the Urban Institute's Health Policy Center on the reports released Monday.