That didn't go quite as planned for Fox News.
In its report on the event, Fox News also draws attention to the audience's response to the question.
The surge by Sanders is indicative of a hard-left shift within the Democratic Party. On Monday, the network will air five town halls in a row, back-to-back - and all in one night.
Asked whether his plans bring big price tags that would drive up the national debt, the Democratic presidential contender scoffed at the suggestion, saying his plans for more taxes on the wealthy and the biggest multinational corporations would cover the costs of his ideas.
The event that so irked President Donald Trump and FNC primetime star Sean Hannity thumped its cable news competition combined in both metrics.
During his first presidential bid, Sanders was also reluctant to make his financial information public, releasing only his 2014 tax return.
Sanders - who has railed against the top 1 percent of earners - is among the top 1 percent income bracket in the country, according to his tax filings.
So far, those have shown that Harris and her husband made the most money, paid the most in taxes and were taxed at the highest rate.
Sanders in a statement said the returns "show that our family has been very fortunate".
He said that his view has always been that the wealthiest Americans ought to pay more taxes.
Nor is there any suggestion that Sanders would moderate his anti-plutocratic politics to benefit him personally.
Taxes paid: $697,611, or 37%. Amy Klobuchar of Minnesota released 12 years of tax returns through 2017 earlier this month. That year, Sanders disclosed $1.31 million income, combined from his Senate salary and $961,000 in book royalties and sales.
Governor Jay Inslee of Washington released 12 years of tax returns, showing that he and his wife earned US$202,912 last year.
The US$1.7m ($2.5m) puts them in America's highest income brackets, according to tax returns released by the presidential candidate today.
"I don't think it's a problem that someone has been successful in the private sector", said Sullivan, who supported Hillary Clinton in the 2016 primary.
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