The GOP tax bill currently being considered in the House would not satisfy stringent Senate rules for avoiding a filibuster, according to an analysis out Tuesday.

Republicans plan on using budget reconciliation, which only requires a simple majority, to pass their tax plan in the Senate. But if portions of the legislation do not adhere to the Byrd rule, named after late Sen. Robert Byrd (D-W.Va.), they can be subjected to the regular 60-vote threshold, which would allow Democrats to tank the bill.

“We estimate the legislation would add about $155 billion to the deficit in 2028; the Byrd rule does not allow reconciliation legislation to add to the deficit at all beyond the budget window (which currently ends in 2027),” the Committee for a Responsible Federal Budget (CRFB) wrote in an review of the legislation.

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Changing that could require Republicans to make corporate tax cuts temporary, which the group said could undermine the economic growth they hope to stimulate with the reform.

The bill, the CRFB noted, could also violate the Byrd rule in other, smaller ways.

“For example, it generates $74 billion in 'off-budget' revenue for Social Security, including $53 billion in additional revenue from certain business income being reclassified as wage income as well as other smaller provisions increasing the amount of taxable wage income. The Senate Parliamentarian may rule some of these provisions to be direct enough changes to the Social Security payroll tax that they cannot remain in the legislation without it losing privilege,” the group wrote.

The Senate is working on its own version of the bill, which may be released as soon as Thursday .

The House and Senate must work out any differences between the two bills for the measure to move forward.