The cost of the plan is a problem for Republican congressional leaders.
Opposition has sprung up in the Republican party and with major U.S. employers to parts of Paul Ryan’s preferred plan.
Some tax law experts say Trump could unilaterally end the so-called “carried interest” loophole.
Republicans -- and President-elect Donald Trump -- have no agreement on how to replace coverage for about 20 million people.
Republicans lawmakers are exploring how the Trump administration can quickly trim required benefits and lower costs.
But it would be a modest tax hike for some of the lowest earners, a new study found.
Abolishing it would save more than $20 billion a year for the millionaires and billionaires the tax applies to.
Some party leaders are wary of sparking a fight over a popular program.
Their opposition to any benefit cuts in the retirement program have turned deficit-reduction politics upside down.