• Senate Republicans released modifications to their massive tax bill on Tuesday night.
• The biggest proposed change: Individual tax cuts would sunset after 2025.
• The bill would also repeal the Affordable Care Act's so-called individual mandate.

Senate Republicans released a massive heap of changes to their tax bill Tuesday night, including tweaks to proposed individual tax cuts and to the way startup employees get paid.

Sen. Orrin Hatch, the Republican chair of the Senate Finance Committee, released a new version of the legislation that, significantly, would sunset individual tax cuts after 2025. That means the proposed tax cuts for Americans would end in 2026, after which the tax brackets would revert to today's levels absent new legislation from Congress.

Other changes to the individual side of taxes, like the repeal of the alternative minimum tax and the increased standard deduction, would also expire after 2025.

While the individual changes would be temporary, cuts to the corporate tax rate would be permanent in the bill. Hatch said in a statement accompanying the updated bill that the bill aimed to provide certainty for American businesses.

"Additionally, the modified mark creates more permanence in our tax system so that American job creators can invest in the long term, grow their business, and create new jobs," Hatch said.

Obamacare changes and more

The legislation also would repeal the Affordable Care Act's so-called individual mandate, eliminating the tax penalty for not carrying health insurance. According to an estimate by the nonpartisan Congressional Budget Office, the move would erase $338 billion from the federal budget deficit over 10 years. It would also cause a serious shake-up in the individual insurance market, leaving a projected 13 million more people without health coverage in 2027 compared with the current system, according to the CBO.

The provisions to make the individual tax cuts temporary and to repeal Obamacare's individual mandate will surely meet tough resistance from Democrats. They could even complicate the math for Republicans to get the 50 Senate votes they need on the bill.

Here's a rundown of some of the other major changes in the updated Senate legislation:

• Adjustments to
• Increasing the size of the child tax credit:
• Elimination of changes from the original bill to stock compensation:
• Easing restrictions on pass-through income: