The House bill would make two big changes. First, for high-income households, it would expand the tax to include all business income, whether or not the taxpayer materially participates in the business, as long as that income is not already subject to payroll taxes. In effect, S Corporation shareholders, limited partners, and other owners of pass-through business who now are exempt would get hit by the NIIT.
Second, solely for that active income, the House bill would raise the income threshold to $400,000 . That would require two separate income thresholds, a feature that exclude the vast majority of business owners but also would make filing more complex .Nearly 99 percent of households would be entirely exempt from the new tax simply because they fall below that $400,000 threshold. TPC estimates that about 88 percent of the expanded NIIT would be paid by the top 1 percent.
The rest, about 12 percent, would be paid by those making between about $372,000 and $885,000 (those between the 95