At least one business group has shifted from opponent to cautious supporter of a House Republican bill to overhaul the tax system. At the same time, association reaction to a Senate Republican tax bill released Thursday was notably muted.

The National Federation of Independent Business had previously opposed the House effort because many small businesses would not be able to take advantage of the lower pass-through rate proposed in the legislation. But on Thursday, House Ways and Means Committee Chairman Kevin Brady (R-Texas) offered an amendment to address NFIB's objections.

In a statement, NFIB CEO Juanita Duggan said the amendment "would create substantial tax relief for millions of small business owners who were left out of the original bill." But she stopped short of endorsing the entire bill.

"We urge Republican and Democratic members of the House to support this amendment going forward," she said.

So far the changes suggested for the House plan have not been enough to sway the minds of two other major critics of the legislation. Both the National Association of Home Builders and National Association of Realtors remain opposed to the plan.

Senate Republicans release their own plan Thursday that addresses one of the main objections of both groups. The House bill would reduce the existing mortgage deduction interest cap from $1 million to $500,000. The Senate bill would leave the deduction alone. Still, the differences in the Senate bill were not enough to win over NAR.

"We've already seen that a near-doubling of the standard deduction, combined with the elimination of other deductions like the state-and-local tax deduction, can turn the American dream into a nightmare for families, as the rug is pulled out from under them," NAR President Elizabeth Mendenhall said. "Simply preserving the mortgage interest deduction in name only isn't enough to protect homeownership."

NAHB released a statement Friday afternoon saying the Senate bill was a step in the right direction.

"However, though the Senate bill provides meaningful tax relief for small businesses and keeps the complete Low-Income Housing Tax Credit program in place, we still believe that maintaining an effective homeownership tax benefit is vitally important," NAHB board chairman Granger MacDonald said.

Other business groups that had previously praised the House plan either didn't comment on the Senate plan or reacted to it with less enthusiasm than the release of the House bill last week. One possible reason is the Senate bill delays a proposed cut in the corporate tax rate until 2019, whereas the House bill would implement the cut next year.

One exception to the silence was the U.S. Chamber of Commerce, which welcomed the "pro-growth measure."

"As we did in the House, the U.S. Chamber will evaluate the policy changes with our members and work with policymakers to ensure this tax legislation is as pro-growth as possible," Chamber Senior Vice President and Chief Policy Officer Neil Bradley said.

MORE CEO DATELINE

• Education groups sound alarm on eliminating college tax breaks
• Energy groups blast federal plan to subsidize coal, nuclear power
• Tech groups give tentative support to bill to reduce online sex trafficking
• Court orders search engines to stop linking to site pirating ACS papers
• Psychological association disputes alleged link between mental illness, gun violence