In a joint statement, White House officials and CongressionalGOP leaders on tax reform said the controversialborder-adjusted tax would be left out of efforts to reform thecountry’s tax code.

The news interjects a new angle of uncertainty for the fate ofthe tax-preferred treatment of workplace retirement savings plans andIRAs.

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The tax, which had been favored by House majority leader PaulRyan, R-WI, would have imposed new levies on imported goods, andwas designed to offset the revenue lost from lowering the corporateand individual tax rates. According to some estimates, the taxwould have raised upwards of $1 trillion in new revenue over 10years.

With that substantial “pay for” now off the table, the questiongoing forward is how aggressively Republicans can cut tax rates,and what existing exemptions in the code will have to be eliminatedto pay for those cuts.

The non-partisan Joint Committee on Taxation, which advisesCongress with research on the tax code, says the tax-preferredtreatment of defined contribution plans will cost $583.6 billion inforegone revenue between 2016 and 2020. Traditional IRAs will cost$85.8 billion. Together, the tax-preferred treatment of retirementsavings plans represent one of the largest sources of foregonerevenue in the tax code.

Related: What is Washington doing to my 401(k) taxbreak?

House Republicans’ Blueprint for Tax Reform would cut thecorporate tax rate from 35 percent to 20 percent. As a candidate,President Trump vowed to cut the corporate rate to 15 percent. TheWhite House has pledged to reduce the existing seven tax bracketsfor individuals to three.

White House officials have signaled the intent to use the budgetreconciliation process to pass tax reform. That would require asimple majority in the Senate to pass, but it would also requirethat a new tax package be revenue-neutral.

The joint statement from the White House announcing the end ofthe border-adjusted tax offered few other specifics as to howRepublicans intend to pay for tax reform, or to what level rateswould be lowered.

Congressional members have reportedly been considering a rangeof reforms to the tax-treatment of retirement plans. The mostaggressive plan would move all pre-tax contributions to 401(k)s toa Roth after-tax contribution system.

Another idea reportedly being considered would take a hybridapproach, capping the amount of pre-tax contributions to half ofthe statutorily allowable contribution limits. The other half wouldbe invested in an after-tax Roth account.

Employer and retirement advocacy groups have been pressinglawmakers to protect the tax-preferred treatment of retirementplans, even as those same groups back efforts to reform the taxcode.

“As thousands of Baby Boomers reach retirement age daily, theyare facing complicated challenges in attaining the financialsecurity they desire for their retirement. To help them addressthose challenges, it is critical that tax reform do all that ispossible to safeguard provisions that encourage and enhance theirabilities to save for a secure and dignified retirement,” saidCathy Weatherford, CEO of the Insured Retirement Institute, in astatement responding to news that the border-adjusted tax was beingeliminated from consideration.

Weatherford said the IRI, which represents the interests ofasset managers, broker dealers, and insurance companies, has beenmeeting with Trump administration officials and committee membersin the House and Senate who will draft tax legislation.

“We remain strongly in favor and urge the members of Congressand the representatives of the President who are engaged in the taxreform conversation to keep the goal of protecting and enhancingthe way the current tax code treats retirement savings at theforefront of their discussions,” said Weatherford.